xrender fix

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

.builds/freebsd.yml

@@ -12,6 +12,7 @@ packages:
   - uthash
   - libconfig
   - libglvnd
+  - libepoxy
   - dbus
   - pcre
 sources:
@@ -19,7 +20,7 @@ sources:
 tasks:
   - setup: |
       cd picom
-      CPPFLAGS="-I/usr/local/include" meson -Dunittest=true build
+      CPPFLAGS="-I/usr/local/include" meson setup -Dunittest=true --werror build
   - build: |
       cd picom
       ninja -C build

.builds/openbsd.yml

@@ -0,0 +1,23 @@
+image: openbsd/latest
+packages:
+  - libev
+  - xcb
+  - meson
+  - pkgconf
+  - cmake
+  - uthash
+  - libconfig
+  - dbus
+  - pcre2
+sources:
+  - https://github.com/yshui/picom
+tasks:
+  - setup: |
+      cd picom
+      CPPFLAGS="-I/usr/local/include" LDFLAGS="-L/usr/local/lib" meson setup -Dunittest=true --werror build
+  - build: |
+      cd picom
+      ninja -C build
+  - unittest: |
+      cd picom
+      ninja -C build test

.circleci/config.yml

@@ -29,7 +29,7 @@ commands:
             - ".git"
       - run:
           name: config
-          command: CC=<< parameters.cc >> meson << parameters.build-config >> -Dunittest=true --werror . build
+          command: CC=<< parameters.cc >> meson setup << parameters.build-config >> -Dunittest=true --werror . build
       - run:
           name: build
           command: ninja -vC build

.clang-tidy

@@ -23,5 +23,9 @@ CheckOptions:
     value: 255.0;1.0;
   - key: readability-function-cognitive-complexity.IgnoreMacros
     value: true
+  - key: readability-function-cognitive-complexity.Threshold
+    value: 50
   - key: readability-function-cognitive-complexity.DescribeBasicIncrements
     value: true
+  - key: bugprone-signed-char-misuse.CharTypdefsToIgnore
+    value: int8_t

.editorconfig

@@ -3,3 +3,6 @@ root = true
 indent_style = tab
 indent_size = 8
 max_line_length = 90
+[*.nix]
+indent_style = space
+indent_size = 2

.github/workflows/codeql-analysis.yml

@@ -18,11 +18,11 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v2
+      uses: github/codeql-action/init@v3
       with:
         languages: ${{ matrix.language }}
 
@@ -32,7 +32,7 @@ jobs:
 
     # Autobuild
     - name: Autobuild
-      uses: github/codeql-action/autobuild@v2
+      uses: github/codeql-action/autobuild@v3
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v2
+      uses: github/codeql-action/analyze@v3

.github/workflows/coding-style-pr.yml

@@ -6,8 +6,8 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - run: git fetch --depth=1 origin ${{ github.event.pull_request.base.sha }}
-    - uses: yshui/git-clang-format-lint@v1.14
+    - uses: yshui/git-clang-format-lint@v1.15
       with:
         base: ${{ github.event.pull_request.base.sha }}

.github/workflows/coding-style.yml

@@ -6,9 +6,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 2
-    - uses: yshui/git-clang-format-lint@v1.14
+    - uses: yshui/git-clang-format-lint@v1.15
       with:
         base: ${{ github.event.ref }}~1

.gitignore

@@ -1,5 +1,6 @@
 # Build files
 .deps
+.direnv
 aclocal.m4
 autom4te.cache
 config.log
@@ -15,6 +16,7 @@ compton
 build/
 compile_commands.json
 build.ninja
+make.sh
 
 # language servers
 .ccls-cache

CHANGELOG.md

@@ -0,0 +1,74 @@
+# Unreleased
+
+## New features
+
+* Allow `corner-radius-rules` to override `corner-radius = 0`. Previously setting corner radius to 0 globally disables rounded corners. (#1170)
+
+## Notable changes
+
+* Marginally improve performance when resizing/opening/closing windows. (#1190)
+
+# v11.2 (2024-Feb-13)
+
+## Build changes
+
+* `picom` now depends on `libepoxy` for OpenGL symbol management.
+
+## Bug fixes
+
+* Workaround a NVIDIA problem that causes high CPU usage after suspend/resume (#1172, #1168)
+* Fix building on OpenBSD (#1189, #1188)
+* Fix occasional freezes (#1040, #1145, #1166)
+* Fix `corner-radius-rules` not applying sometimes (#1177)
+* Fix window shader not having an effect when frame opacity is enabled (#1174)
+* Fix binding root pixmap in case of depth mismatch (#984)
+
+# v11.1 (2024-Jan-28)
+
+## Bug fixes
+
+* Fix missing fading on window close for some window managers. (#704)
+
+# v11 (2024-Jan-20)
+
+## Build changes
+
+* Due to some caveats discovered related to setting the `CAP_SYS_NICE` capability, it is now recommended to **NOT** set this capability for picom.
+
+## Deprecations
+
+* Uses of `--sw-opti`, and `--respect-prop-shadow` are now hard errors.
+* `-F` has been removed completely. It was deprecated before the picom fork.
+
+# v11-rc1 (2024-Jan-14)
+
+## Notable features
+
+* picom now uses dithering to prevent banding. Banding is most notable when using a strong background blur. (#952)
+* Frame pacing. picom uses present feedback information to schedule new frames when it makes sense to do so. This improves latency, and replaces the `glFlush` and `GL_MaxFramesAllowed=1` hacks we used to do for NVIDIA. (#968 #1156)
+* Some missing features have been implemented for the EGL backend (#1004 #1007)
+
+## Bug fixes
+
+* Many memory/resource leak fixes thanks to @absolutelynothelix . (#977 #978 #979 #980 #982 #985 #992 #1009 #1022)
+* Fix tiling of wallpaper. (#1002)
+* Fix some blur artifacts (#1095)
+* Fix shadow color for transparent shadows (#1124)
+* Don't spam logs when another compositor is running (#1104)
+* Fix rounded corners showing as black with the xrender backend (#1003)
+* Fix blur with rounded windows (#950)
+
+## Build changes
+
+* Dependency `pcre` has been replaced by `pcre2`.
+* New dependency `xcb-util`.
+* `xinerama` is no longer used.
+* `picom` now tries to give itself a real-time scheduling priority. ~~Please consider giving `picom` the `CAP_SYS_NICE` capability when packaging it.~~
+
+## Deprecations
+
+* The `kawase` blur method is removed. Note this is just an alias to the `dual_kawase` method, which is still available. (#1102)
+
+# Earlier versions
+
+Please see the GitHub releases page.

CONTRIBUTORS

@@ -34,6 +34,7 @@ hasufell <julian.ospald at googlemail.com>
 i-c-u-p
 Ignacio Taranto <ignacio.taranto at eclypsium.com>
 Istvan Petres
+Ivan Malison <ivanmalison at gmail.com>
 Jake <jakeroggenbuck2 at gmail.com>
 James Cloos <cloos at jhcloos.com>
 Jamey Sharp <jamey at minilop.net>
@@ -43,6 +44,7 @@ Javeed Shaikh <syscrash2k at gmail.com>
 Jerónimo Navarro <jnavarro at ancasrl.com.ar>
 jialeens <jialeadmin at 163.com>
 Johnny Pribyl <pribylsnbits at gmail.com>
+Jose Maldonado aka Yukiteru <josemald89 at gmail.com>
 Keith Packard <keithp at keithp.com>
 Kevin Kelley <kelleyk at kelleyk.net>
 ktprograms <ktprograms at gmail.com>
@@ -68,6 +70,7 @@ Peter Mattern <matternp at arcor.de>
 Phil Blundell <pb at reciva.com>
 Que Quotion <quequotion at bugmenot.com>
 Rafael Kitover <rkitover at gmail.com>
+Reith
 Richard Grenville <pyxlcy at gmail.com>
 Rytis Karpuska <rytis.karpuska at gmail.com>
 Samuel Hand <samuel.d.hand at gmail.com>

README.md

@@ -41,7 +41,7 @@ Assuming you already have all the usual building tools installed (e.g. gcc, pyth
 * pixman
 * libdbus (optional, disable with the `-Ddbus=false` meson configure flag)
 * libconfig (optional, disable with the `-Dconfig_file=false` meson configure flag)
-* libGL, libEGL (optional, disable with the `-Dopengl=false` meson configure flag)
+* libGL, libEGL, libepoxy (optional, disable with the `-Dopengl=false` meson configure flag)
 * libpcre2 (optional, disable with the `-Dregex=false` meson configure flag)
 * libev
 * uthash
@@ -49,13 +49,13 @@ Assuming you already have all the usual building tools installed (e.g. gcc, pyth
 On Debian based distributions (e.g. Ubuntu), the needed packages are
 
 ```
-libconfig-dev libdbus-1-dev libegl-dev libev-dev libgl-dev libpcre2-dev libpixman-1-dev libx11-xcb-dev libxcb1-dev libxcb-composite0-dev libxcb-damage0-dev libxcb-dpms0-dev libxcb-glx0-dev libxcb-image0-dev libxcb-present-dev libxcb-randr0-dev libxcb-render0-dev libxcb-render-util0-dev libxcb-shape0-dev libxcb-util-dev libxcb-xfixes0-dev libxext-dev meson ninja-build uthash-dev
+libconfig-dev libdbus-1-dev libegl-dev libev-dev libgl-dev libepoxy-dev libpcre2-dev libpixman-1-dev libx11-xcb-dev libxcb1-dev libxcb-composite0-dev libxcb-damage0-dev libxcb-dpms0-dev libxcb-glx0-dev libxcb-image0-dev libxcb-present-dev libxcb-randr0-dev libxcb-render0-dev libxcb-render-util0-dev libxcb-shape0-dev libxcb-util-dev libxcb-xfixes0-dev libxext-dev meson ninja-build uthash-dev
 ```
 
 On Fedora, the needed packages are
 
 ```
-dbus-devel gcc git libconfig-devel libdrm-devel libev-devel libX11-devel libX11-xcb libXext-devel libxcb-devel libGL-devel libEGL-devel meson pcre2-devel pixman-devel uthash-devel xcb-util-image-devel xcb-util-renderutil-devel xorg-x11-proto-devel
+dbus-devel gcc git libconfig-devel libdrm-devel libev-devel libX11-devel libX11-xcb libXext-devel libxcb-devel libGL-devel libEGL-devel libepoxy-devel meson pcre2-devel pixman-devel uthash-devel xcb-util-image-devel xcb-util-renderutil-devel xorg-x11-proto-devel xcb-util-devel
 ```
 
 To build the documents, you need `asciidoc`
@@ -85,12 +85,23 @@ $ ninja -C build
 
 ### To install
 
+#### AUR (arch)
+- picom-ftlabs-git
+Thanks to @Fxzzi for maintaining the package.
+
+
 ``` bash
 $ ninja -C build install
 ```
 
 Default install prefix is `/usr/local`, you can change it with `meson configure -Dprefix=<path> build`
 
+## Running
+To launch with all animations as a background process you can use:
+`picom --animations -b`
+
+To only have specific animations, enable them with cli flags (see `picom --help`) or add them to your picom config.
+
 ## How to Contribute
 
 All contributions are welcome!

flake.lock

@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1689068808,
-        "narHash": "sha256-6ixXo3wt24N/melDWjq70UuHQLxGV8jZvooRanIHXw0=",
+        "lastModified": 1705309234,
+        "narHash": "sha256-uNRRNRKmJyCRC/8y1RqBkqWBLM034y4qN7EprSdmgyA=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "919d646de7be200f3bf08cb76ae1f09402b6f9b4",
+        "rev": "1ef2e671c3b0c19053962c07dbda38332dcebf26",
         "type": "github"
       },
       "original": {
@@ -25,11 +25,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1660459072,
-        "narHash": "sha256-8DFJjXG8zqoONA1vXtgeKXy68KdJL5UaXR8NtVMUbx8=",
+        "lastModified": 1703887061,
+        "narHash": "sha256-gGPa9qWNc6eCXT/+Z5/zMkyYOuRZqeFZBDbopNZQkuY=",
         "owner": "hercules-ci",
         "repo": "gitignore.nix",
-        "rev": "a20de23b925fd8264fd7fad6454652e142fd7f73",
+        "rev": "43e1aa1308018f37118e34d3a9cb4f5e75dc11d5",
         "type": "github"
       },
       "original": {
@@ -41,11 +41,12 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1691186842,
-        "narHash": "sha256-wxBVCvZUwq+XS4N4t9NqsHV4E64cPVqQ2fdDISpjcw0=",
-        "path": "/nix/store/d42v5grfq77vr10r336kks0qjp0wij8d-source",
-        "rev": "18036c0be90f4e308ae3ebcab0e14aae0336fe42",
-        "type": "path"
+        "lastModified": 1705856552,
+        "narHash": "sha256-JXfnuEf5Yd6bhMs/uvM67/joxYKoysyE3M2k6T3eWbg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "612f97239e2cc474c13c9dafa0df378058c5ad8d",
+        "type": "github"
       },
       "original": {
         "id": "nixpkgs",

flake.nix

@@ -7,28 +7,55 @@
     };
   };
   outputs = {
-    self, flake-utils, nixpkgs, git-ignore-nix, ...
-  }: flake-utils.lib.eachDefaultSystem (system: let
-    overlay = self: super: {
-      picom = super.picom.overrideAttrs (oldAttrs: rec {
-        pname = "picom";
-        buildInputs = [
-          self.pcre2 self.xorg.xcbutil
-        ] ++ self.lib.remove self.xorg.libXinerama (
-          self.lib.remove self.pcre oldAttrs.buildInputs
-        );
-        src = git-ignore-nix.lib.gitignoreSource ./.;
-      });
-    };
-    pkgs = import nixpkgs { inherit system overlays; config.allowBroken = true; };
-    overlays = [ overlay ];
-  in rec {
-    inherit overlay overlays;
-    defaultPackage = pkgs.picom;
-    devShell = defaultPackage.overrideAttrs {
-      buildInputs = defaultPackage.buildInputs ++ [
-        pkgs.clang-tools
-      ];
-    };
-  });
+    self,
+    flake-utils,
+    nixpkgs,
+    git-ignore-nix,
+    ...
+  }:
+    flake-utils.lib.eachDefaultSystem (system: let
+      overlay = self: super: {
+        picom = super.picom.overrideAttrs (oldAttrs: rec {
+          version = "11";
+          pname = "picom";
+          buildInputs =
+            [
+              self.pcre2
+              self.xorg.xcbutil
+              self.libepoxy
+            ]
+            ++ self.lib.remove self.xorg.libXinerama (
+              self.lib.remove self.pcre oldAttrs.buildInputs
+            );
+          src = git-ignore-nix.lib.gitignoreSource ./.;
+        });
+      };
+
+      pkgs = import nixpkgs {
+        inherit system overlays;
+        config.allowBroken = true;
+      };
+
+      overlays = [overlay];
+    in rec {
+      inherit
+        overlay
+        overlays
+        ;
+      defaultPackage = pkgs.picom;
+      devShell = defaultPackage.overrideAttrs {
+        buildInputs =
+          defaultPackage.buildInputs
+          ++ (with pkgs; [
+            clang-tools_17
+            llvmPackages_17.clang-unwrapped.python
+          ]);
+        hardeningDisable = ["fortify"];
+        shellHook = ''
+          # Workaround a NixOS limitation on sanitizers:
+          # See: https://github.com/NixOS/nixpkgs/issues/287763
+          export LD_LIBRARY_PATH+=":/run/opengl-driver/lib"
+        '';
+      };
+    });
 }

man/picom.1.asciidoc

@@ -49,9 +49,6 @@ OPTIONS
 *-f*, *--fading*::
 	Fade windows in/out when opening/closing and when opacity changes, unless *--no-fading-openclose* is used.
 
-*-F*::
-	Equals to *-f*. Deprecated.
-
 *-i*, *--inactive-opacity*='OPACITY'::
 	Opacity of inactive windows. (0.1 - 1.0, defaults to 1.0)
 
@@ -393,6 +390,7 @@ uniform float corner_radius;  // corner radius of the window (pixels)
 uniform float border_width;   // estimated border width of the window (pixels)
 uniform bool invert_color;    // whether to invert the color of the window
 uniform sampler2D tex;        // texture of the window
+uniform vec2 effective_size;  // effective dimensions of the texture (repeats pixels if larger than tex)
 uniform sampler2D brightness; // estimated brightness of the window, 1x1 texture
 uniform float max_brightness; // configured maximum brightness of the window (0.0 - 1.0)
 uniform float time;           // time in milliseconds, counting from an unspecified starting point
@@ -418,7 +416,8 @@ vec4 default_post_processing(vec4 c);
 // 1) fetch the specified pixel
 // 2) apply default post-processing
 vec4 window_shader() {
-    vec4 c = texelFetch(tex, ivec2(texcoord), 0);
+    vec2 texsize = textureSize(tex, 0);
+    vec4 c = texture2D(tex, texcoord / texsize, 0);
     return default_post_processing(c);
 }
 ----

meson.build

@@ -1,4 +1,4 @@
-project('picom', 'c', version: '10',
+project('picom', 'c', version: '11',
         default_options: ['c_std=c11', 'warning_level=1'])
 
 cc = meson.get_compiler('c')

picom.sample.conf

@@ -1,29 +1,76 @@
+#################################
+#           Animations         #
+
+# !These animations WILL NOT work correctly for any other wm other than phyOS-dwm fork!
+
+# fly-in: Windows fly in from random directions to the screen
+# maximize: Windows pop from center of the screen to their respective positions
+# minimize: Windows minimize from their position to the center of the screen
+# slide-in-center: Windows move from upper-center of the screen to their respective positions
+# slide-out-center: Windows move to the upper-center of the screen
+# slide-left: Windows are created from the right-most window position and slide leftwards
+# slide right: Windows are created from the left-most window position and slide rightwards
+# slide-down: Windows are moved from the top of the screen and slide downward
+# slide-up: Windows are moved from their position to top of the screen
+# squeeze: Windows are either closed or created to/from their center y-position (the animation is similar to a blinking eye)
+# squeeze-bottom: Similar to squeeze, but the animation starts from bottom-most y-position
+# zoom: Windows are either created or destroyed from/to their center (not the screen center)
+
+#################################
+
+#enable or disable animations
+animations = true;
+#change animation speed of windows in current tag e.g open window in current tag
+animation-stiffness-in-tag = 125;
+#change animation speed of windows when tag changes
+animation-stiffness-tag-change = 90.0;
+
+animation-window-mass = 0.4;
+animation-dampening = 15;
+animation-clamping = true;
+
+#open windows
+animation-for-open-window = "zoom";
+#minimize or close windows
+animation-for-unmap-window = "squeeze";
+#popup windows
+animation-for-transient-window = "slide-up"; #available options: slide-up, slide-down, slide-left, slide-right, squeeze, squeeze-bottom, zoom
+
+#set animation for windows being transitioned out while changings tags
+animation-for-prev-tag = "minimize";
+#enables fading for windows being transitioned out while changings tags
+enable-fading-prev-tag = true;
+
+#set animation for windows being transitioned in while changings tags
+animation-for-next-tag = "slide-in-center";
+#enables fading for windows being transitioned in while changings tags
+enable-fading-next-tag = true;
+
 #################################
 #             Shadows           #
 #################################
 
-
 # Enabled client-side shadows on windows. Note desktop windows
 # (windows with '_NET_WM_WINDOW_TYPE_DESKTOP') never get shadow,
 # unless explicitly requested using the wintypes option.
 #
 # shadow = false
-shadow = true;
+shadow = false;
 
 # The blur radius for shadows, in pixels. (defaults to 12)
 # shadow-radius = 12
-shadow-radius = 7;
+shadow-radius = 60;
 
 # The opacity of shadows. (0.0 - 1.0, defaults to 0.75)
 # shadow-opacity = .75
 
 # The left offset for shadows, in pixels. (defaults to -15)
 # shadow-offset-x = -15
-shadow-offset-x = -7;
+shadow-offset-x = -20;
 
 # The top offset for shadows, in pixels. (defaults to -15)
 # shadow-offset-y = -15
-shadow-offset-y = -7;
+shadow-offset-y = -20;
 
 # Red color value of shadow (0.0 - 1.0, defaults to 0).
 # shadow-red = 0
@@ -48,6 +95,9 @@ shadow-exclude = [
   "class_g = 'Conky'",
   "class_g ?= 'Notify-osd'",
   "class_g = 'Cairo-clock'",
+  "class_g = 'dwm'",
+  "class_g = 'chromium'",
+  "class_g *?= 'slop'",
   "_GTK_FRAME_EXTENTS@:c"
 ];
 
@@ -73,19 +123,18 @@ shadow-exclude = [
 
 # Fade windows in/out when opening/closing and when opacity changes,
 #  unless no-fading-openclose is used.
-# fading = false
 fading = true;
 
 # Opacity change between steps while fading in. (0.01 - 1.0, defaults to 0.028)
 # fade-in-step = 0.028
-fade-in-step = 0.03;
+fade-in-step = 0.023;
 
 # Opacity change between steps while fading out. (0.01 - 1.0, defaults to 0.03)
 # fade-out-step = 0.03
-fade-out-step = 0.03;
+fade-out-step = 0.035;
 
 # The time between steps in fade step, in milliseconds. (> 0, defaults to 10)
-# fade-delta = 10
+fade-delta = 10
 
 # Specify a list of conditions of windows that should not be faded.
 # fade-exclude = []
@@ -104,15 +153,13 @@ fade-out-step = 0.03;
 
 # Opacity of inactive windows. (0.1 - 1.0, defaults to 1.0)
 # inactive-opacity = 1
-inactive-opacity = 0.8;
 
 # Opacity of window titlebars and borders. (0.1 - 1.0, disabled by default)
 # frame-opacity = 1.0
-frame-opacity = 0.7;
 
 # Let inactive opacity set by -i override the '_NET_WM_WINDOW_OPACITY' values of windows.
 # inactive-opacity-override = true
-inactive-opacity-override = false;
+inactive-opacity-override = true;
 
 # Default opacity for active windows. (0.0 - 1.0, defaults to 1.0)
 # active-opacity = 1.0
@@ -122,21 +169,13 @@ inactive-opacity-override = false;
 
 # Specify a list of conditions of windows that should never be considered focused.
 # focus-exclude = []
-focus-exclude = [ "class_g = 'Cairo-clock'" ];
+focus-exclude = [
+"class_g = 'Cairo-clock'" ,
+];
 
 # Use fixed inactive dim value, instead of adjusting according to window opacity.
 # inactive-dim-fixed = 1.0
 
-# Specify a list of opacity rules, in the format `PERCENT:PATTERN`,
-# like `50:name *= "Firefox"`. picom-trans is recommended over this.
-# Note we don't make any guarantee about possible conflicts with other
-# programs that set '_NET_WM_WINDOW_OPACITY' on frame or client windows.
-# example:
-#    opacity-rule = [ "80:class_g = 'URxvt'" ];
-#
-# opacity-rule = []
-
-
 #################################
 #           Corners             #
 #################################
@@ -144,52 +183,21 @@ focus-exclude = [ "class_g = 'Cairo-clock'" ];
 # Sets the radius of rounded window corners. When > 0, the compositor will
 # round the corners of windows. Does not interact well with
 # `transparent-clipping`.
-corner-radius = 0
+corner-radius = 11;
 
 # Exclude conditions for rounded corners.
-rounded-corners-exclude = [
-  "window_type = 'dock'",
-  "window_type = 'desktop'"
-];
+#rounded-corners-exclude = [
+#  "window_type = 'dock'",
+#  "window_type = 'desktop'"
+#];
 
-
-#################################
-#     Background-Blurring       #
-#################################
-
-
-# Parameters for background blurring, see the *BLUR* section for more information.
-# blur-method =
-# blur-size = 12
-#
-# blur-deviation = false
-#
-# blur-strength = 5
-
-# Blur background of semi-transparent / ARGB windows.
-# Bad in performance, with driver-dependent behavior.
-# The name of the switch may change without prior notifications.
-#
-# blur-background = false
-
-# Blur background of windows when the window frame is not opaque.
-# Implies:
-#    blur-background
-# Bad in performance, with driver-dependent behavior. The name may change.
-#
-# blur-background-frame = false
-
-
-# Use fixed blur strength rather than adjusting according to window opacity.
-# blur-background-fixed = false
-
-
-# Specify the blur convolution kernel, with the following format:
-# example:
-#   blur-kern = "5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1";
-#
-# blur-kern = ""
-blur-kern = "3x3box";
+blur: {
+  method = "dual_kawase";
+  strength = 9;
+  background = true;
+  background-frame = false;
+  background-fixed = false;
+}
 
 
 # Exclude conditions for background blur.
@@ -197,24 +205,25 @@ blur-kern = "3x3box";
 blur-background-exclude = [
   "window_type = 'dock'",
   "window_type = 'desktop'",
-  "_GTK_FRAME_EXTENTS@:c"
+  "_GTK_FRAME_EXTENTS@:c",
+  "class_g = 'Chromium'",
+  "class_g = 'Discord'",
+  "class_g = 'Dunst'",
+  "class_g = 'Peek'",
+  "class_g *?= 'slop'",
 ];
 
 #################################
 #       General Settings        #
 #################################
 
-# Enable remote control via D-Bus. See the man page for more details.
-# dbus = true
-
 # Daemonize process. Fork to background after initialization. Causes issues with certain (badly-written) drivers.
 # daemon = false
 
 # Specify the backend to use: `xrender`, `glx`, `egl` or `xr_glx_hybrid`.
 # `xrender` is the default one.
 #
-# backend = "glx"
-backend = "xrender";
+backend = "glx"
 
 # Use higher precision during rendering, and apply dither when presenting the
 # rendered screen. Reduces banding artifacts, but might cause performance
@@ -222,8 +231,7 @@ backend = "xrender";
 dithered-present = false;
 
 # Enable/disable VSync.
-# vsync = false
-vsync = true;
+# vsync = true
 
 # Try to detect WM windows (a non-override-redirect window with no
 # child that has 'WM_STATE') and mark them as active.
@@ -239,25 +247,25 @@ mark-ovredir-focused = true;
 # shaped windows. The accuracy is not very high, unfortunately.
 #
 # detect-rounded-corners = false
-detect-rounded-corners = true;
+detect-rounded-corners = false;
 
 # Detect '_NET_WM_WINDOW_OPACITY' on client windows, useful for window managers
 # not passing '_NET_WM_WINDOW_OPACITY' of client windows to frame windows.
 #
 # detect-client-opacity = false
-detect-client-opacity = true;
+detect-client-opacity = false;
 
 # Use EWMH '_NET_ACTIVE_WINDOW' to determine currently focused window,
 # rather than listening to 'FocusIn'/'FocusOut' event. Might have more accuracy,
 # provided that the WM supports it.
 #
-# use-ewmh-active-win = false
+use-ewmh-active-win = true;
 
 # Unredirect all windows if a full-screen opaque window is detected,
 # to maximize performance for full-screen windows. Known to cause flickering
 # when redirecting/unredirecting windows.
 #
-# unredir-if-possible = false
+unredir-if-possible = false;
 
 # Delay before unredirecting the window, in milliseconds. Defaults to 0.
 # unredir-if-possible-delay = 0
@@ -301,7 +309,7 @@ detect-transient = true;
 # practically happened) and may not work with blur-background.
 # My tests show a 15% performance boost. Recommended.
 #
-# glx-no-stencil = false
+glx-no-stencil = true;
 
 # GLX backend: Avoid rebinding pixmap on window damage.
 # Probably could improve performance on rapid window content changes,
@@ -322,24 +330,18 @@ use-damage = true;
 # calls are finished before picom starts drawing. Needed on nvidia-drivers
 # with GLX backend for some users.
 #
-# xrender-sync-fence = false
+xrender-sync-fence = true;
 
-# GLX backend: Use specified GLSL fragment shader for rendering window
-# contents. Read the man page for a detailed explanation of the interface.
+# GLX backend: Use specified GLSL fragment shader for rendering window contents.
+# See `compton-default-fshader-win.glsl` and `compton-fake-transparency-fshader-win.glsl`
+# in the source tree for examples.
 #
-# window-shader-fg = "default"
-
-# Use rules to set per-window shaders. Syntax is SHADER_PATH:PATTERN, similar
-# to opacity-rule. SHADER_PATH can be "default". This overrides window-shader-fg.
-#
-# window-shader-fg-rule = [
-#   "my_shader.frag:window_type != 'dock'"
-# ]
+window-shader-fg = "default";
 
 # Force all windows to be painted with blending. Useful if you
 # have a glx-fshader-win that could turn opaque pixels transparent.
 #
-# force-win-blend = false
+# force-win-blend = true;
 
 # Do not use EWMH to detect fullscreen windows.
 # Reverts to checking if a window is fullscreen based only on its size and coordinates.
@@ -356,7 +358,7 @@ use-damage = true;
 # Make transparent windows clip other windows like non-transparent windows do,
 # instead of blending on top of them.
 #
-# transparent-clipping = false
+transparent-clipping = false;
 
 # Specify a list of conditions of windows that should never have transparent
 # clipping applied. Useful for screenshot tools, where you need to be able to
@@ -429,3 +431,9 @@ wintypes:
   popup_menu = { opacity = 0.8; }
   dropdown_menu = { opacity = 0.8; }
 };
+
+opacity-rule = [
+  "100:class_g = 'St' && focused",
+  "50:class_g = 'St' && !focused",
+  "100:fullscreen",
+];

src/atom.c

@@ -2,12 +2,20 @@
 #include <xcb/xcb.h>
 
 #include "atom.h"
+#include "cache.h"
 #include "common.h"
-#include "utils.h"
+#include "compiler.h"
 #include "log.h"
+#include "utils.h"
 
-static inline void *atom_getter(void *ud, const char *atom_name, int *err) {
-	xcb_connection_t *c = ud;
+struct atom_entry {
+	struct cache_handle entry;
+	xcb_atom_t atom;
+};
+
+static inline int atom_getter(struct cache *cache attr_unused, const char *atom_name,
+                              struct cache_handle **value, void *user_data) {
+	xcb_connection_t *c = user_data;
 	xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(
 	    c, xcb_intern_atom(c, 0, to_u16_checked(strlen(atom_name)), atom_name), NULL);
 
@@ -18,9 +26,32 @@ static inline void *atom_getter(void *ud, const char *atom_name, int *err) {
 		free(reply);
 	} else {
 		log_error("Failed to intern atoms");
-		*err = 1;
+		return -1;
 	}
-	return (void *)(intptr_t)atom;
+
+	struct atom_entry *entry = ccalloc(1, struct atom_entry);
+	entry->atom = atom;
+	*value = &entry->entry;
+	return 0;
+}
+
+static inline void
+atom_entry_free(struct cache *cache attr_unused, struct cache_handle *handle) {
+	struct atom_entry *entry = cache_entry(handle, struct atom_entry, entry);
+	free(entry);
+}
+
+xcb_atom_t get_atom(struct atom *a, const char *key, xcb_connection_t *c) {
+	struct cache_handle *entry = NULL;
+	if (cache_get_or_fetch(&a->c, key, &entry, c, atom_getter) < 0) {
+		log_error("Failed to get atom %s", key);
+		return XCB_NONE;
+	}
+	return cache_entry(entry, struct atom_entry, entry)->atom;
+}
+
+xcb_atom_t get_atom_cached(struct atom *a, const char *key) {
+	return cache_entry(cache_get(&a->c, key), struct atom_entry, entry)->atom;
 }
 
 /**
@@ -28,10 +59,15 @@ static inline void *atom_getter(void *ud, const char *atom_name, int *err) {
  */
 struct atom *init_atoms(xcb_connection_t *c) {
 	auto atoms = ccalloc(1, struct atom);
-	atoms->c = new_cache((void *)c, atom_getter, NULL);
-#define ATOM_GET(x) atoms->a##x = (xcb_atom_t)(intptr_t)cache_get(atoms->c, #x, NULL)
+	atoms->c = CACHE_INIT;
+#define ATOM_GET(x) atoms->a##x = get_atom(atoms, #x, c)
 	LIST_APPLY(ATOM_GET, SEP_COLON, ATOM_LIST1);
 	LIST_APPLY(ATOM_GET, SEP_COLON, ATOM_LIST2);
 #undef ATOM_GET
 	return atoms;
 }
+
+void destroy_atoms(struct atom *a) {
+	cache_invalidate_all(&a->c, atom_entry_free);
+	free(a);
+}

src/atom.h

@@ -1,6 +1,4 @@
 #pragma once
-#include <stdlib.h>
-
 #include <xcb/xcb.h>
 
 #include "cache.h"
@@ -23,6 +21,7 @@
 	WM_CLIENT_MACHINE, \
 	_NET_ACTIVE_WINDOW, \
 	_COMPTON_SHADOW, \
+	COMPTON_VERSION, \
 	_NET_WM_WINDOW_TYPE, \
 	_XROOTPMAP_ID, \
 	ESETROOT_PMAP_ID, \
@@ -52,19 +51,18 @@
 
 #define ATOM_DEF(x) xcb_atom_t a##x
 
+struct atom_entry;
 struct atom {
-	struct cache *c;
+	struct cache c;
 	LIST_APPLY(ATOM_DEF, SEP_COLON, ATOM_LIST1);
 	LIST_APPLY(ATOM_DEF, SEP_COLON, ATOM_LIST2);
 };
 
-struct atom *init_atoms(xcb_connection_t *);
+/// Create a new atom object with a xcb connection. `struct atom` does not hold
+/// a reference to the connection.
+struct atom *init_atoms(xcb_connection_t *c);
 
-static inline xcb_atom_t get_atom(struct atom *a, const char *key) {
-	return (xcb_atom_t)(intptr_t)cache_get(a->c, key, NULL);
-}
+xcb_atom_t get_atom(struct atom *a, const char *key, xcb_connection_t *c);
+xcb_atom_t get_atom_cached(struct atom *a, const char *key);
 
-static inline void destroy_atoms(struct atom *a) {
-	cache_free(a->c);
-	free(a);
-}
+void destroy_atoms(struct atom *a);

src/backend/backend.c

@@ -56,6 +56,58 @@ region_t get_damage(session_t *ps, bool all_damage) {
 	return region;
 }
 
+static void process_window_for_painting(session_t *ps, struct managed_win *w,
+                                        void *win_image, double additional_alpha,
+                                        region_t *reg_bound, region_t *reg_visible,
+                                        region_t *reg_paint, region_t *reg_paint_in_bound) {
+	// For window image processing, we don't have to limit the process
+	// region to damage for correctness. (see <damager-note> for
+	// details)
+
+	// The visible region, in window local coordinates Although we
+	// don't limit process region to damage, we provide that info in
+	// reg_visible as a hint. Since window image data outside of the
+	// damage region won't be painted onto target
+	coord_t window_coord = {.x = w->g.x, .y = w->g.y};
+	coord_t dest_coord = {.x = w->g.x + w->widthb, .y = w->g.y + w->heightb};
+
+	region_t reg_visible_local;
+	region_t reg_bound_local;
+	{
+		// The bounding shape, in window local coordinates
+		pixman_region32_init(&reg_bound_local);
+		pixman_region32_copy(&reg_bound_local, reg_bound);
+		pixman_region32_translate(&reg_bound_local, -w->g.x, -w->g.y);
+
+		pixman_region32_init(&reg_visible_local);
+		pixman_region32_intersect(&reg_visible_local, reg_visible, reg_paint);
+		pixman_region32_translate(&reg_visible_local, -w->g.x, -w->g.y);
+		// Data outside of the bounding shape won't be visible,
+		// but it is not necessary to limit the image operations
+		// to the bounding shape yet. So pass that as the visible
+		// region, not the clip region.
+		pixman_region32_intersect(&reg_visible_local, &reg_visible_local,
+		                          &reg_bound_local);
+	}
+
+	auto new_img = ps->backend_data->ops->clone_image(ps->backend_data, win_image,
+	                                                  &reg_visible_local);
+	auto reg_frame = win_get_region_frame_local_by_val(w);
+	double alpha = additional_alpha * w->opacity;
+	ps->backend_data->ops->set_image_property(
+	    ps->backend_data, IMAGE_PROPERTY_OPACITY, new_img, &alpha);
+	ps->backend_data->ops->image_op(ps->backend_data, IMAGE_OP_APPLY_ALPHA, new_img,
+	                                &reg_frame, &reg_visible_local,
+	                                (double[]){w->frame_opacity});
+	pixman_region32_fini(&reg_frame);
+	ps->backend_data->ops->compose(ps->backend_data, new_img,
+			       window_coord, NULL, dest_coord,
+			       reg_paint_in_bound, reg_visible, true);
+	ps->backend_data->ops->release_image(ps->backend_data, new_img);
+	pixman_region32_fini(&reg_visible_local);
+	pixman_region32_fini(&reg_bound_local);
+}
+
 void handle_device_reset(session_t *ps) {
 	log_error("Device reset detected");
 	// Wait for reset to complete
@@ -82,13 +134,17 @@ void handle_device_reset(session_t *ps) {
 }
 
 /// paint all windows
-void paint_all_new(session_t *ps, struct managed_win *t) {
+///
+/// Returns if any render command is issued. IOW if nothing on the screen has changed,
+/// this function will return false.
+bool paint_all_new(session_t *ps, struct managed_win *const t) {
 	struct timespec now = get_time_timespec();
 	auto paint_all_start_us =
 	    (uint64_t)now.tv_sec * 1000000UL + (uint64_t)now.tv_nsec / 1000;
 	if (ps->backend_data->ops->device_status &&
 	    ps->backend_data->ops->device_status(ps->backend_data) != DEVICE_STATUS_NORMAL) {
-		return handle_device_reset(ps);
+		handle_device_reset(ps);
+		return false;
 	}
 	if (ps->o.xrender_sync_fence) {
 		if (ps->xsync_exists && !x_fence_sync(&ps->c, ps->sync_fence)) {
@@ -114,7 +170,7 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 
 	if (!pixman_region32_not_empty(&reg_damage)) {
 		pixman_region32_fini(&reg_damage);
-		return;
+		return false;
 	}
 
 #ifdef DEBUG_REPAINT
@@ -190,16 +246,15 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 	auto after_damage_us = (uint64_t)now.tv_sec * 1000000UL + (uint64_t)now.tv_nsec / 1000;
 	log_trace("Getting damage took %" PRIu64 " us", after_damage_us - after_sync_fence_us);
 	if (ps->next_render > 0) {
-		log_trace("Render schedule deviation: %ld us (%s) %" PRIu64 " %ld",
-		          labs((long)after_damage_us - (long)ps->next_render),
-		          after_damage_us < ps->next_render ? "early" : "late",
-		          after_damage_us, ps->next_render);
+		log_verbose("Render schedule deviation: %ld us (%s) %" PRIu64 " %" PRIu64,
+		            labs((long)after_damage_us - (long)ps->next_render),
+		            after_damage_us < ps->next_render ? "early" : "late",
+		            after_damage_us, ps->next_render);
 		ps->last_schedule_delay = 0;
 		if (after_damage_us > ps->next_render) {
 			ps->last_schedule_delay = after_damage_us - ps->next_render;
 		}
 	}
-	ps->did_render = true;
 
 	if (ps->backend_data->ops->prepare) {
 		ps->backend_data->ops->prepare(ps->backend_data, &reg_paint);
@@ -207,8 +262,8 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 
 	if (ps->root_image) {
 		ps->backend_data->ops->compose(ps->backend_data, ps->root_image,
-		                               (coord_t){0}, NULL, (coord_t){0},
-		                               &reg_paint, &reg_visible);
+		                               (coord_t){0}, NULL, (coord_t){.x = ps->root_width, .y = ps->root_height},
+		                               &reg_paint, &reg_visible, true);
 	} else {
 		ps->backend_data->ops->fill(ps->backend_data, (struct color){0, 0, 0, 1},
 		                            &reg_paint);
@@ -219,7 +274,7 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 	// on top of that window. This is used to reduce the number of pixels painted.
 	//
 	// Whether this is beneficial is to be determined XXX
-	for (auto w = t; w; w = w->prev_trans) {
+	for (struct managed_win *w = t; w; w = w->prev_trans) {
 		pixman_region32_subtract(&reg_visible, &ps->screen_reg, w->reg_ignore);
 		assert(!(w->flags & WIN_FLAGS_IMAGE_ERROR));
 		assert(!(w->flags & WIN_FLAGS_PIXMAP_STALE));
@@ -259,6 +314,7 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 		 * option */
 		auto real_win_mode = w->mode;
 		coord_t window_coord = {.x = w->g.x, .y = w->g.y};
+		coord_t dest_coord = {.x = w->g.x + w->widthb, .y = w->g.y + w->heightb};
 
 		if (w->blur_background &&
 		    (ps->o.force_win_blend || real_win_mode == WMODE_TRANS ||
@@ -387,7 +443,7 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 			}
 			ps->backend_data->ops->compose(
 			    ps->backend_data, w->shadow_image, shadow_coord,
-			    inverted_mask, window_coord, &reg_shadow, &reg_visible);
+			    inverted_mask, window_coord, &reg_shadow, &reg_visible, false);
 			if (inverted_mask) {
 				ps->backend_data->ops->set_image_property(
 				    ps->backend_data, IMAGE_PROPERTY_INVERTED,
@@ -431,6 +487,17 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 				ps->backend_data->ops->set_image_property(
 				    ps->backend_data, IMAGE_PROPERTY_BORDER_WIDTH,
 				    w->win_image, &border_width);
+				if (w->old_win_image) {
+					// TODO(dccsillag): explain why the following is
+					// "necessary"
+					double zero = 0.0;
+					ps->backend_data->ops->set_image_property(
+					    ps->backend_data, IMAGE_PROPERTY_BORDER_WIDTH,
+					    w->old_win_image, &zero);
+					ps->backend_data->ops->set_image_property(
+					    ps->backend_data, IMAGE_PROPERTY_CORNER_RADIUS,
+					    w->old_win_image, &zero);
+				}
 			}
 
 			ps->backend_data->ops->set_image_property(
@@ -453,53 +520,43 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 		}
 
 		// Draw window on target
-		if (w->frame_opacity == 1) {
+		bool is_animating = 0 <= w->animation_progress && w->animation_progress < 1.0;
+		if (w->frame_opacity == 1 && !is_animating) {
 			ps->backend_data->ops->compose(ps->backend_data, w->win_image,
-			                               window_coord, NULL, window_coord,
-			                               &reg_paint_in_bound, &reg_visible);
+			                               window_coord, NULL, dest_coord,
+			                               &reg_paint_in_bound, &reg_visible, true);
 		} else {
-			// For window image processing, we don't have to limit the process
-			// region to damage for correctness. (see <damager-note> for
-			// details)
+			if (is_animating && w->old_win_image) {
+				bool is_focused = win_is_focused_raw(w);
+				if (!is_focused && w->focused && w->opacity_is_set)
+					is_focused = true;
+				assert(w->old_win_image);
 
-			// The visible region, in window local coordinates Although we
-			// don't limit process region to damage, we provide that info in
-			// reg_visible as a hint. Since window image data outside of the
-			// damage region won't be painted onto target
-			region_t reg_visible_local;
-			region_t reg_bound_local;
-			{
-				// The bounding shape, in window local coordinates
-				pixman_region32_init(&reg_bound_local);
-				pixman_region32_copy(&reg_bound_local, &reg_bound);
-				pixman_region32_translate(&reg_bound_local, -w->g.x, -w->g.y);
+				bool resizing =
+					w->g.width != w->pending_g.width ||
+					w->g.height != w->pending_g.height;
 
-				pixman_region32_init(&reg_visible_local);
-				pixman_region32_intersect(&reg_visible_local,
-				                          &reg_visible, &reg_paint);
-				pixman_region32_translate(&reg_visible_local, -w->g.x,
-				                          -w->g.y);
-				// Data outside of the bounding shape won't be visible,
-				// but it is not necessary to limit the image operations
-				// to the bounding shape yet. So pass that as the visible
-				// region, not the clip region.
-				pixman_region32_intersect(
-				    &reg_visible_local, &reg_visible_local, &reg_bound_local);
+				// Only animate opacity here if we are resizing
+				// a transparent window
+				process_window_for_painting(ps, w, w->win_image,
+								is_focused ? 1.0 : w->opacity >= 1 ? 1.0 : w->animation_progress,
+								&reg_bound, &reg_visible,
+								&reg_paint, &reg_paint_in_bound);
+
+				// Only do this if size changes as otherwise moving
+				// transparent windows will flicker and if you just
+				// move so slightly they will keep flickering
+				if (resizing && (!is_focused || !w->opacity_is_set)) {
+					process_window_for_painting(ps, w, w->old_win_image,
+									1.0 - w->animation_progress,
+									&reg_bound, &reg_visible,
+									&reg_paint, &reg_paint_in_bound);
+				}
+			} else {
+				process_window_for_painting(
+				    ps, w, w->win_image, 1.0, &reg_bound, &reg_visible,
+				    &reg_paint, &reg_paint_in_bound);
 			}
-
-			auto new_img = ps->backend_data->ops->clone_image(
-			    ps->backend_data, w->win_image, &reg_visible_local);
-			auto reg_frame = win_get_region_frame_local_by_val(w);
-			ps->backend_data->ops->image_op(
-			    ps->backend_data, IMAGE_OP_APPLY_ALPHA, new_img, &reg_frame,
-			    &reg_visible_local, (double[]){w->frame_opacity});
-			pixman_region32_fini(&reg_frame);
-			ps->backend_data->ops->compose(ps->backend_data, new_img,
-			                               window_coord, NULL, window_coord,
-			                               &reg_paint_in_bound, &reg_visible);
-			ps->backend_data->ops->release_image(ps->backend_data, new_img);
-			pixman_region32_fini(&reg_visible_local);
-			pixman_region32_fini(&reg_bound_local);
 		}
 	skip:
 		pixman_region32_fini(&reg_bound);
@@ -541,6 +598,7 @@ void paint_all_new(session_t *ps, struct managed_win *t) {
 	for (win *w = t; w; w = w->prev_trans)
 		log_trace(" %#010lx", w->id);
 #endif
+	return true;
 }
 
 // vim: set noet sw=8 ts=8 :

src/backend/backend.h

@@ -115,6 +115,10 @@ struct dual_kawase_blur_args {
 	int strength;
 };
 
+typedef struct {
+	// Intentionally left blank
+} *image_handle;
+
 struct backend_operations {
 	// ===========    Initialization    ===========
 
@@ -167,26 +171,27 @@ struct backend_operations {
 	 * Paint the content of an image onto the rendering buffer.
 	 *
 	 * @param backend_data the backend data
-	 * @param image_data   the image to paint
+	 * @param image        the image to paint, cannot be NULL
 	 * @param dst_x, dst_y the top left corner of the image in the target
 	 * @param mask         the mask image, the top left of the mask is aligned with
-	 *                     the top left of the image
+	 *                     the top left of the image. Optional, can be
+	 *                     NULL.
 	 * @param reg_paint    the clip region, in target coordinates
 	 * @param reg_visible  the visible region, in target coordinates
 	 */
-	void (*compose)(backend_t *backend_data, void *image_data, coord_t image_dst,
-	                void *mask, coord_t mask_dst, const region_t *reg_paint,
-	                const region_t *reg_visible);
+	void (*compose)(backend_t *backend_data, image_handle image, coord_t image_dst,
+	                image_handle mask, coord_t mask_dst, const region_t *reg_paint,
+	                const region_t *reg_visible, bool lerp) attr_nonnull(1, 2, 6, 7);
 
 	/// Fill rectangle of the rendering buffer, mostly for debug purposes, optional.
 	void (*fill)(backend_t *backend_data, struct color, const region_t *clip);
 
 	/// Blur a given region of the rendering buffer.
 	///
-	/// The blur is limited by `mask`. `mask_dst` specifies the top left corner of the
-	/// mask is.
-	bool (*blur)(backend_t *backend_data, double opacity, void *blur_ctx, void *mask,
-	             coord_t mask_dst, const region_t *reg_blur,
+	/// The blur can be limited by `mask`. `mask_dst` specifies the top left corner of
+	/// the mask. `mask` can be NULL.
+	bool (*blur)(backend_t *backend_data, double opacity, void *blur_ctx,
+	             image_handle mask, coord_t mask_dst, const region_t *reg_blur,
 	             const region_t *reg_visible) attr_nonnull(1, 3, 6, 7);
 
 	/// Update part of the back buffer with the rendering buffer, then present the
@@ -202,13 +207,15 @@ struct backend_operations {
 	 * Bind a X pixmap to the backend's internal image data structure.
 	 *
 	 * @param backend_data backend data
-	 * @param pixmap X pixmap to bind
-	 * @param fmt information of the pixmap's visual
-	 * @param owned whether the ownership of the pixmap is transfered to the backend
-	 * @return backend internal data structure bound with this pixmap
+	 * @param pixmap       X pixmap to bind
+	 * @param fmt          information of the pixmap's visual
+	 * @param owned        whether the ownership of the pixmap is transferred to the
+	 *                     backend.
+	 * @return             backend specific image handle for the pixmap. May be
+	 *                     NULL.
 	 */
-	void *(*bind_pixmap)(backend_t *backend_data, xcb_pixmap_t pixmap,
-	                     struct xvisual_info fmt, bool owned);
+	image_handle (*bind_pixmap)(backend_t *backend_data, xcb_pixmap_t pixmap,
+	                            struct xvisual_info fmt, bool owned);
 
 	/// Create a shadow context for rendering shadows with radius `radius`.
 	/// Default implementation: default_create_shadow_context
@@ -220,21 +227,27 @@ struct backend_operations {
 	                               struct backend_shadow_context *ctx);
 
 	/// Create a shadow image based on the parameters. Resulting image should have a
-	/// size of `width + radisu * 2` x `height + radius * 2`. Radius is set when the
+	/// size of `width + radius * 2` x `height + radius * 2`. Radius is set when the
 	/// shadow context is created.
 	/// Default implementation: default_render_shadow
 	///
+	/// @return the shadow image, may be NULL.
+	///
 	/// Required.
-	void *(*render_shadow)(backend_t *backend_data, int width, int height,
-	                       struct backend_shadow_context *ctx, struct color color);
+	image_handle (*render_shadow)(backend_t *backend_data, int width, int height,
+	                              struct backend_shadow_context *ctx, struct color color);
 
 	/// Create a shadow by blurring a mask. `size` is the size of the blur. The
 	/// backend can use whichever blur method is the fastest. The shadow produced
 	/// shoule be consistent with `render_shadow`.
 	///
+	/// @param mask the input mask, must not be NULL.
+	/// @return the shadow image, may be NULL.
+	///
 	/// Optional.
-	void *(*shadow_from_mask)(backend_t *backend_data, void *mask,
-	                          struct backend_shadow_context *ctx, struct color color);
+	image_handle (*shadow_from_mask)(backend_t *backend_data, image_handle mask,
+	                                 struct backend_shadow_context *ctx,
+	                                 struct color color);
 
 	/// Create a mask image from region `reg`. This region can be used to create
 	/// shadow, or used as a mask for composing. When used as a mask, it should mask
@@ -245,13 +258,18 @@ struct backend_operations {
 	/// and outside of the mask. Corner radius should exclude the corners from the
 	/// mask. Corner radius should be applied before the inversion.
 	///
+	/// @return the mask image, may be NULL.
+	///
 	/// Required.
-	void *(*make_mask)(backend_t *backend_data, geometry_t size, const region_t *reg);
+	image_handle (*make_mask)(backend_t *backend_data, geometry_t size,
+	                          const region_t *reg);
 
 	// ============ Resource management ===========
 
 	/// Free resources associated with an image data structure
-	void (*release_image)(backend_t *backend_data, void *img_data) attr_nonnull(1, 2);
+	///
+	/// @param image the image to be released, cannot be NULL.
+	void (*release_image)(backend_t *backend_data, image_handle image) attr_nonnull(1, 2);
 
 	/// Create a shader object from a shader source.
 	///
@@ -276,12 +294,14 @@ struct backend_operations {
 	/// This function is needed because some backend might change the content of the
 	/// window (e.g. when using a custom shader with the glx backend), so only the
 	/// backend knows if an image is transparent.
-	bool (*is_image_transparent)(backend_t *backend_data, void *image_data)
+	///
+	/// @param image the image to be checked, must not be NULL.
+	bool (*is_image_transparent)(backend_t *backend_data, image_handle image)
 	    attr_nonnull(1, 2);
 
-	/// Get the age of the buffer content we are currently rendering ontop
+	/// Get the age of the buffer content we are currently rendering on top
 	/// of. The buffer that has just been `present`ed has a buffer age of 1.
-	/// Everytime `present` is called, buffers get older. Return -1 if the
+	/// Every time `present` is called, buffers get older. Return -1 if the
 	/// buffer is empty.
 	///
 	/// Optional
@@ -290,7 +310,7 @@ struct backend_operations {
 	/// Get the render time of the last frame. If the render is still in progress,
 	/// returns false. The time is returned in `ts`. Frames are delimited by the
 	/// present() calls. i.e. after a present() call, last_render_time() should start
-	/// reporting the time of the just presen1ted frame.
+	/// reporting the time of the just presented frame.
 	///
 	/// Optional, if not available, the most conservative estimation will be used.
 	bool (*last_render_time)(backend_t *backend_data, struct timespec *ts);
@@ -311,35 +331,39 @@ struct backend_operations {
 	 *
 	 * @param backend_data backend data
 	 * @param prop         the property to change
-	 * @param image_data   an image data structure returned by the backend
+	 * @param image        an image handle, cannot be NULL.
 	 * @param args         property value
-	 * @return whether the operation is successful
+	 * @return             whether the operation is successful
 	 */
 	bool (*set_image_property)(backend_t *backend_data, enum image_properties prop,
-	                           void *image_data, void *args);
+	                           image_handle image, void *args) attr_nonnull(1, 3);
 
 	/**
 	 * Manipulate an image. Image properties are untouched.
 	 *
 	 * @param backend_data backend data
 	 * @param op           the operation to perform
-	 * @param image_data   an image data structure returned by the backend
+	 * @param image        an image handle, cannot be NULL.
 	 * @param reg_op       the clip region, define the part of the image to be
 	 *                     operated on.
 	 * @param reg_visible  define the part of the image that will eventually
 	 *                     be visible on target. this is a hint to the backend
 	 *                     for optimization purposes.
 	 * @param args         extra arguments, operation specific
-	 * @return whether the operation is successful
+	 * @return             whether the operation is successful
 	 */
-	bool (*image_op)(backend_t *backend_data, enum image_operations op, void *image_data,
-	                 const region_t *reg_op, const region_t *reg_visible, void *args);
+	bool (*image_op)(backend_t *backend_data, enum image_operations op,
+	                 image_handle image, const region_t *reg_op,
+	                 const region_t *reg_visible, void *args) attr_nonnull(1, 3, 4, 5);
 
-	/// Create another instance of the `image_data`. All `image_op` and
-	/// `set_image_property` calls on the returned image should not affect the
-	/// original image
-	void *(*clone_image)(backend_t *base, const void *image_data,
-	                     const region_t *reg_visible);
+	/// Create another instance of the `image`. The newly created image
+	/// inherits its content and all image properties from the image being
+	/// cloned. All `image_op` and `set_image_property` calls on the
+	/// returned image should not affect the original image.
+	///
+	/// @param image the image to be cloned, must not be NULL.
+	image_handle (*clone_image)(backend_t *base, image_handle image,
+	                            const region_t *reg_visible) attr_nonnull_all;
 
 	/// Create a blur context that can be used to call `blur`
 	void *(*create_blur_context)(backend_t *base, enum blur_method, void *args);
@@ -366,4 +390,8 @@ struct backend_operations {
 
 extern struct backend_operations *backend_list[];
 
-void paint_all_new(session_t *ps, struct managed_win *const t) attr_nonnull(1);
+/// paint all windows
+///
+/// Returns if any render command is issued. IOW if nothing on the screen has changed,
+/// this function will return false.
+bool paint_all_new(session_t *ps, struct managed_win *t) attr_nonnull(1);

src/backend/backend_common.c

@@ -293,8 +293,8 @@ shadow_picture_err:
 	return false;
 }
 
-void *default_render_shadow(backend_t *backend_data, int width, int height,
-                            struct backend_shadow_context *sctx, struct color color) {
+image_handle default_render_shadow(backend_t *backend_data, int width, int height,
+                                   struct backend_shadow_context *sctx, struct color color) {
 	const conv *kernel = (void *)sctx;
 	xcb_render_picture_t shadow_pixel =
 	    solid_picture(backend_data->c, true, 1, color.red, color.green, color.blue);
@@ -308,7 +308,7 @@ void *default_render_shadow(backend_t *backend_data, int width, int height,
 	}
 
 	auto visual = x_get_visual_for_standard(backend_data->c, XCB_PICT_STANDARD_ARGB_32);
-	void *ret = backend_data->ops->bind_pixmap(
+	auto ret = backend_data->ops->bind_pixmap(
 	    backend_data, shadow, x_get_visual_info(backend_data->c, visual), true);
 	x_free_picture(backend_data->c, pict);
 	x_free_picture(backend_data->c, shadow_pixel);
@@ -316,16 +316,16 @@ void *default_render_shadow(backend_t *backend_data, int width, int height,
 }
 
 /// Implement render_shadow with shadow_from_mask
-void *
+image_handle
 backend_render_shadow_from_mask(backend_t *backend_data, int width, int height,
                                 struct backend_shadow_context *sctx, struct color color) {
 	region_t reg;
 	pixman_region32_init_rect(&reg, 0, 0, (unsigned int)width, (unsigned int)height);
-	void *mask = backend_data->ops->make_mask(
+	auto mask = backend_data->ops->make_mask(
 	    backend_data, (geometry_t){.width = width, .height = height}, &reg);
 	pixman_region32_fini(&reg);
 
-	void *shadow = backend_data->ops->shadow_from_mask(backend_data, mask, sctx, color);
+	auto shadow = backend_data->ops->shadow_from_mask(backend_data, mask, sctx, color);
 	backend_data->ops->release_image(backend_data, mask);
 	return shadow;
 }
@@ -458,17 +458,17 @@ struct dual_kawase_params *generate_dual_kawase_params(void *args) {
 	return params;
 }
 
-void *default_clone_image(backend_t *base attr_unused, const void *image_data,
-                          const region_t *reg_visible attr_unused) {
+image_handle default_clone_image(backend_t *base attr_unused, image_handle image,
+                                 const region_t *reg_visible attr_unused) {
 	auto new_img = ccalloc(1, struct backend_image);
-	*new_img = *(struct backend_image *)image_data;
+	*new_img = *(struct backend_image *)image;
 	new_img->inner->refcount++;
-	return new_img;
+	return (image_handle)new_img;
 }
 
 bool default_set_image_property(backend_t *base attr_unused, enum image_properties op,
-                                void *image_data, void *arg) {
-	struct backend_image *tex = image_data;
+                                image_handle image, void *arg) {
+	auto tex = (struct backend_image *)image;
 	int *iargs = arg;
 	bool *bargs = arg;
 	double *dargs = arg;
@@ -490,8 +490,8 @@ bool default_set_image_property(backend_t *base attr_unused, enum image_properti
 	return true;
 }
 
-bool default_is_image_transparent(backend_t *base attr_unused, void *image_data) {
-	struct backend_image *img = image_data;
+bool default_is_image_transparent(backend_t *base attr_unused, image_handle image) {
+	auto img = (struct backend_image *)image;
 	return img->opacity < 1 || img->inner->has_alpha;
 }
 

src/backend/backend_common.h

@@ -54,11 +54,11 @@ solid_picture(struct x_connection *, bool argb, double a, double r, double g, do
 xcb_image_t *make_shadow(struct x_connection *c, const conv *kernel, double opacity,
                          int width, int height);
 
-void *default_render_shadow(backend_t *backend_data, int width, int height,
-                            struct backend_shadow_context *sctx, struct color color);
+image_handle default_render_shadow(backend_t *backend_data, int width, int height,
+                                   struct backend_shadow_context *sctx, struct color color);
 
 /// Implement `render_shadow` with `shadow_from_mask`.
-void *
+image_handle
 backend_render_shadow_from_mask(backend_t *backend_data, int width, int height,
                                 struct backend_shadow_context *sctx, struct color color);
 struct backend_shadow_context *
@@ -72,8 +72,8 @@ void init_backend_base(struct backend_base *base, session_t *ps);
 struct conv **generate_blur_kernel(enum blur_method method, void *args, int *kernel_count);
 struct dual_kawase_params *generate_dual_kawase_params(void *args);
 
-void *default_clone_image(backend_t *base, const void *image_data, const region_t *reg);
-bool default_is_image_transparent(backend_t *base attr_unused, void *image_data);
+image_handle default_clone_image(backend_t *base, image_handle image, const region_t *reg);
+bool default_is_image_transparent(backend_t *base attr_unused, image_handle image);
 bool default_set_image_property(backend_t *base attr_unused, enum image_properties op,
-                                void *image_data, void *arg);
+                                image_handle image, void *arg);
 struct backend_image *default_new_backend_image(int w, int h);

src/backend/driver.c

@@ -19,6 +19,16 @@ void apply_driver_workarounds(struct session *ps, enum driver driver) {
 	}
 }
 
+enum vblank_scheduler_type choose_vblank_scheduler(enum driver driver attr_unused) {
+	enum vblank_scheduler_type type = VBLANK_SCHEDULER_PRESENT;
+#ifdef CONFIG_OPENGL
+	if (driver & DRIVER_NVIDIA) {
+		type = VBLANK_SCHEDULER_SGI_VIDEO_SYNC;
+	}
+#endif
+	return type;
+}
+
 enum driver detect_driver(xcb_connection_t *c, backend_t *backend_data, xcb_window_t window) {
 	enum driver ret = 0;
 	// First we try doing backend agnostic detection using RANDR

src/backend/driver.h

@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <xcb/xcb.h>
 
+#include "config.h"
 #include "utils.h"
 
 struct session;
@@ -41,6 +42,8 @@ enum driver detect_driver(xcb_connection_t *, struct backend_base *, xcb_window_
 
 /// Apply driver specified global workarounds. It's safe to call this multiple times.
 void apply_driver_workarounds(struct session *ps, enum driver);
+/// Choose a vblank scheduler based on the driver.
+enum vblank_scheduler_type choose_vblank_scheduler(enum driver driver);
 
 // Print driver names to stdout, for diagnostics
 static inline void print_drivers(enum driver drivers) {

src/backend/dummy/dummy.c

@@ -50,8 +50,9 @@ void dummy_deinit(struct backend_base *data) {
 	free(dummy);
 }
 
-static void dummy_check_image(struct backend_base *base, const struct dummy_image *img) {
+static void dummy_check_image(struct backend_base *base, image_handle image) {
 	auto dummy = (struct dummy_data *)base;
+	auto img = (struct dummy_image *)image;
 	if (img == (struct dummy_image *)&dummy->mask) {
 		return;
 	}
@@ -64,13 +65,13 @@ static void dummy_check_image(struct backend_base *base, const struct dummy_imag
 	assert(*tmp->refcount > 0);
 }
 
-void dummy_compose(struct backend_base *base, void *image, coord_t dst attr_unused,
-                   void *mask attr_unused, coord_t mask_dst attr_unused,
+void dummy_compose(struct backend_base *base, image_handle image, coord_t dst attr_unused,
+                   image_handle mask attr_unused, coord_t mask_dst attr_unused,
                    const region_t *reg_paint attr_unused,
-                   const region_t *reg_visible attr_unused) {
+                   const region_t *reg_visible attr_unused, bool lerp attr_unused) {
 	auto dummy attr_unused = (struct dummy_data *)base;
 	dummy_check_image(base, image);
-	assert(mask == NULL || mask == &dummy->mask);
+	assert(mask == NULL || (struct backend_image *)mask == &dummy->mask);
 }
 
 void dummy_fill(struct backend_base *backend_data attr_unused, struct color c attr_unused,
@@ -78,20 +79,20 @@ void dummy_fill(struct backend_base *backend_data attr_unused, struct color c at
 }
 
 bool dummy_blur(struct backend_base *backend_data attr_unused, double opacity attr_unused,
-                void *blur_ctx attr_unused, void *mask attr_unused,
+                void *blur_ctx attr_unused, image_handle mask attr_unused,
                 coord_t mask_dst attr_unused, const region_t *reg_blur attr_unused,
                 const region_t *reg_visible attr_unused) {
 	return true;
 }
 
-void *dummy_bind_pixmap(struct backend_base *base, xcb_pixmap_t pixmap,
-                        struct xvisual_info fmt, bool owned) {
+image_handle dummy_bind_pixmap(struct backend_base *base, xcb_pixmap_t pixmap,
+                               struct xvisual_info fmt, bool owned) {
 	auto dummy = (struct dummy_data *)base;
 	struct dummy_image *img = NULL;
 	HASH_FIND_INT(dummy->images, &pixmap, img);
 	if (img) {
 		(*img->refcount)++;
-		return img;
+		return (image_handle)img;
 	}
 
 	img = ccalloc(1, struct dummy_image);
@@ -102,12 +103,12 @@ void *dummy_bind_pixmap(struct backend_base *base, xcb_pixmap_t pixmap,
 	img->owned = owned;
 
 	HASH_ADD_INT(dummy->images, pixmap, img);
-	return (void *)img;
+	return (image_handle)img;
 }
 
-void dummy_release_image(backend_t *base, void *image) {
+void dummy_release_image(backend_t *base, image_handle image) {
 	auto dummy = (struct dummy_data *)base;
-	if (image == &dummy->mask) {
+	if ((struct backend_image *)image == &dummy->mask) {
 		return;
 	}
 	auto img = (struct dummy_image *)image;
@@ -123,10 +124,9 @@ void dummy_release_image(backend_t *base, void *image) {
 	}
 }
 
-bool dummy_is_image_transparent(struct backend_base *base, void *image) {
-	auto img = (struct dummy_image *)image;
-	dummy_check_image(base, img);
-	return img->transparent;
+bool dummy_is_image_transparent(struct backend_base *base, image_handle image) {
+	dummy_check_image(base, image);
+	return ((struct dummy_image *)image)->transparent;
 }
 
 int dummy_buffer_age(struct backend_base *base attr_unused) {
@@ -134,29 +134,31 @@ int dummy_buffer_age(struct backend_base *base attr_unused) {
 }
 
 bool dummy_image_op(struct backend_base *base, enum image_operations op attr_unused,
-                    void *image, const region_t *reg_op attr_unused,
+                    image_handle image, const region_t *reg_op attr_unused,
                     const region_t *reg_visible attr_unused, void *args attr_unused) {
 	dummy_check_image(base, image);
 	return true;
 }
 
-void *dummy_make_mask(struct backend_base *base, geometry_t size attr_unused,
-                      const region_t *reg attr_unused) {
-	return &(((struct dummy_data *)base)->mask);
+image_handle dummy_make_mask(struct backend_base *base, geometry_t size attr_unused,
+                             const region_t *reg attr_unused) {
+	auto dummy = (struct dummy_data *)base;
+	auto mask = &dummy->mask;
+	return (image_handle)mask;
 }
 
 bool dummy_set_image_property(struct backend_base *base, enum image_properties prop attr_unused,
-                              void *image, void *arg attr_unused) {
+                              image_handle image, void *arg attr_unused) {
 	dummy_check_image(base, image);
 	return true;
 }
 
-void *dummy_clone_image(struct backend_base *base, const void *image,
-                        const region_t *reg_visible attr_unused) {
-	auto img = (const struct dummy_image *)image;
-	dummy_check_image(base, img);
-	(*img->refcount)++;
-	return (void *)img;
+image_handle dummy_clone_image(struct backend_base *base, image_handle image,
+                               const region_t *reg_visible attr_unused) {
+	dummy_check_image(base, image);
+	auto image_impl = (struct dummy_image *)image;
+	(*image_impl->refcount)++;
+	return image;
 }
 
 void *dummy_create_blur_context(struct backend_base *base attr_unused,

src/backend/gl/blur.c

@@ -256,10 +256,11 @@ bool gl_dual_kawase_blur(double opacity, struct gl_blur_context *bctx, const rec
 	return true;
 }
 
-bool gl_blur_impl(double opacity, struct gl_blur_context *bctx, void *mask, coord_t mask_dst,
-                  const region_t *reg_blur, const region_t *reg_visible attr_unused,
-                  GLuint source_texture, geometry_t source_size, GLuint target_fbo,
-                  GLuint default_mask, bool high_precision) {
+bool gl_blur_impl(double opacity, struct gl_blur_context *bctx,
+                  struct backend_image *mask, coord_t mask_dst, const region_t *reg_blur,
+                  const region_t *reg_visible attr_unused, GLuint source_texture,
+                  geometry_t source_size, GLuint target_fbo, GLuint default_mask,
+                  bool high_precision) {
 	bool ret = false;
 
 	if (source_size.width != bctx->fb_width || source_size.height != bctx->fb_height) {
@@ -400,12 +401,12 @@ bool gl_blur_impl(double opacity, struct gl_blur_context *bctx, void *mask, coor
 	return ret;
 }
 
-bool gl_blur(backend_t *base, double opacity, void *ctx, void *mask, coord_t mask_dst,
+bool gl_blur(backend_t *base, double opacity, void *ctx, image_handle mask, coord_t mask_dst,
              const region_t *reg_blur, const region_t *reg_visible attr_unused) {
 	auto gd = (struct gl_data *)base;
 	auto bctx = (struct gl_blur_context *)ctx;
-	return gl_blur_impl(opacity, bctx, mask, mask_dst, reg_blur, reg_visible,
-	                    gd->back_texture,
+	return gl_blur_impl(opacity, bctx, (struct backend_image *)mask, mask_dst,
+	                    reg_blur, reg_visible, gd->back_texture,
 	                    (geometry_t){.width = gd->width, .height = gd->height},
 	                    gd->back_fbo, gd->default_mask_texture, gd->dithered_present);
 }
@@ -604,9 +605,9 @@ bool gl_create_kernel_blur_context(void *blur_context, GLfloat *projection,
 		bind_uniform(pass, mask_offset);
 		bind_uniform(pass, mask_inverted);
 		bind_uniform(pass, mask_corner_radius);
-		log_info("Uniform locations: %d %d %d %d %d", pass->uniform_mask_tex,
-		         pass->uniform_mask_offset, pass->uniform_mask_inverted,
-		         pass->uniform_mask_corner_radius, pass->uniform_opacity);
+		log_debug("Uniform locations: %d %d %d %d %d", pass->uniform_mask_tex,
+		          pass->uniform_mask_offset, pass->uniform_mask_inverted,
+		          pass->uniform_mask_corner_radius, pass->uniform_opacity);
 		pass->texorig_loc = glGetUniformLocationChecked(pass->prog, "texorig");
 
 		// Setup projection matrix

src/backend/gl/egl.c

@@ -36,12 +36,6 @@ struct egl_data {
 	EGLContext ctx;
 };
 
-static PFNGLEGLIMAGETARGETTEXSTORAGEEXTPROC glEGLImageTargetTexStorage = NULL;
-static PFNEGLCREATEIMAGEKHRPROC eglCreateImageProc = NULL;
-static PFNEGLDESTROYIMAGEKHRPROC eglDestroyImageProc = NULL;
-static PFNEGLGETPLATFORMDISPLAYPROC eglGetPlatformDisplayProc = NULL;
-static PFNEGLCREATEPLATFORMWINDOWSURFACEPROC eglCreatePlatformWindowSurfaceProc = NULL;
-
 const char *eglGetErrorString(EGLint error) {
 #define CASE_STR(value)                                                                  \
 	case value: return #value;
@@ -74,7 +68,7 @@ static void egl_release_image(backend_t *base, struct gl_texture *tex) {
 	struct egl_pixmap *p = tex->user_data;
 	// Release binding
 	if (p->image != EGL_NO_IMAGE) {
-		eglDestroyImageProc(gd->display, p->image);
+		eglDestroyImage(gd->display, p->image);
 		p->image = EGL_NO_IMAGE;
 	}
 
@@ -134,18 +128,6 @@ static backend_t *egl_init(session_t *ps, xcb_window_t target) {
 	bool success = false;
 	struct egl_data *gd = NULL;
 
-#define get_proc(name, type)                                                             \
-	name##Proc = (type)eglGetProcAddress(#name);                                     \
-	if (!name##Proc) {                                                               \
-		log_error("Failed to get EGL function " #name);                          \
-		goto end;                                                                \
-	}
-	get_proc(eglCreateImage, PFNEGLCREATEIMAGEKHRPROC);
-	get_proc(eglDestroyImage, PFNEGLDESTROYIMAGEKHRPROC);
-	get_proc(eglGetPlatformDisplay, PFNEGLGETPLATFORMDISPLAYPROC);
-	get_proc(eglCreatePlatformWindowSurface, PFNEGLCREATEPLATFORMWINDOWSURFACEPROC);
-#undef get_proc
-
 	// Check if we have the X11 platform
 	const char *exts = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
 	if (strstr(exts, "EGL_EXT_platform_x11") == NULL) {
@@ -154,12 +136,12 @@ static backend_t *egl_init(session_t *ps, xcb_window_t target) {
 	}
 
 	gd = ccalloc(1, struct egl_data);
-	gd->display = eglGetPlatformDisplayProc(EGL_PLATFORM_X11_EXT, ps->c.dpy,
-	                                        (EGLAttrib[]){
-	                                            EGL_PLATFORM_X11_SCREEN_EXT,
-	                                            ps->c.screen,
-	                                            EGL_NONE,
-	                                        });
+	gd->display = eglGetPlatformDisplayEXT(EGL_PLATFORM_X11_EXT, ps->c.dpy,
+	                                       (EGLint[]){
+	                                           EGL_PLATFORM_X11_SCREEN_EXT,
+	                                           ps->c.screen,
+	                                           EGL_NONE,
+	                                       });
 	if (gd->display == EGL_NO_DISPLAY) {
 		log_error("Failed to get EGL display.");
 		goto end;
@@ -212,7 +194,7 @@ static backend_t *egl_init(session_t *ps, xcb_window_t target) {
 	// clang-format on
 
 	gd->target_win =
-	    eglCreatePlatformWindowSurfaceProc(gd->display, config, &target, NULL);
+	    eglCreatePlatformWindowSurfaceEXT(gd->display, config, &target, NULL);
 	if (gd->target_win == EGL_NO_SURFACE) {
 		log_error("Failed to create EGL surface.");
 		goto end;
@@ -243,14 +225,6 @@ static backend_t *egl_init(session_t *ps, xcb_window_t target) {
 		goto end;
 	}
 
-	glEGLImageTargetTexStorage =
-	    (PFNGLEGLIMAGETARGETTEXSTORAGEEXTPROC)eglGetProcAddress("glEGLImageTargetTexS"
-	                                                            "torageEXT");
-	if (glEGLImageTargetTexStorage == NULL) {
-		log_error("Failed to get glEGLImageTargetTexStorageEXT.");
-		goto end;
-	}
-
 	gd->gl.decouple_texture_user_data = egl_decouple_user_data;
 	gd->gl.release_user_data = egl_release_image;
 
@@ -275,7 +249,7 @@ end:
 	return &gd->gl.base;
 }
 
-static void *
+static image_handle
 egl_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, bool owned) {
 	struct egl_data *gd = (void *)base;
 	struct egl_pixmap *eglpixmap = NULL;
@@ -302,9 +276,8 @@ egl_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, b
 
 	eglpixmap = cmalloc(struct egl_pixmap);
 	eglpixmap->pixmap = pixmap;
-	eglpixmap->image =
-	    eglCreateImageProc(gd->display, EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR,
-	                       (EGLClientBuffer)(uintptr_t)pixmap, NULL);
+	eglpixmap->image = eglCreateImage(gd->display, EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR,
+	                                  (EGLClientBuffer)(uintptr_t)pixmap, NULL);
 	eglpixmap->owned = owned;
 
 	if (eglpixmap->image == EGL_NO_IMAGE) {
@@ -324,14 +297,14 @@ egl_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, b
 	wd->dim = 0;
 	wd->inner->refcount = 1;
 	glBindTexture(GL_TEXTURE_2D, inner->texture);
-	glEGLImageTargetTexStorage(GL_TEXTURE_2D, eglpixmap->image, NULL);
+	glEGLImageTargetTexStorageEXT(GL_TEXTURE_2D, eglpixmap->image, NULL);
 	glBindTexture(GL_TEXTURE_2D, 0);
 
 	gl_check_err();
-	return wd;
+	return (image_handle)wd;
 err:
 	if (eglpixmap && eglpixmap->image) {
-		eglDestroyImageProc(gd->display, eglpixmap->image);
+		eglDestroyImage(gd->display, eglpixmap->image);
 	}
 	free(eglpixmap);
 
@@ -422,41 +395,6 @@ struct backend_operations egl_ops = {
     .max_buffer_age = 5,        // Why?
 };
 
-PFNEGLGETDISPLAYDRIVERNAMEPROC eglGetDisplayDriverName;
-/**
- * Check if a EGL extension exists.
- */
-static inline bool egl_has_extension(EGLDisplay dpy, const char *ext) {
-	const char *egl_exts = eglQueryString(dpy, EGL_EXTENSIONS);
-	if (!egl_exts) {
-		log_error("Failed get EGL extension list.");
-		return false;
-	}
-
-	auto inlen = strlen(ext);
-	const char *curr = egl_exts;
-	bool match = false;
-	while (curr && !match) {
-		const char *end = strchr(curr, ' ');
-		if (!end) {
-			// Last extension string
-			match = strcmp(ext, curr) == 0;
-		} else if (curr + inlen == end) {
-			// Length match, do match string
-			match = strncmp(ext, curr, (unsigned long)(end - curr)) == 0;
-		}
-		curr = end ? end + 1 : NULL;
-	}
-
-	if (!match) {
-		log_info("Missing EGL extension %s.", ext);
-	} else {
-		log_info("Found EGL extension %s.", ext);
-	}
-
-	return match;
-}
-
 struct eglext_info eglext = {0};
 
 void eglext_init(EGLDisplay dpy) {
@@ -464,7 +402,10 @@ void eglext_init(EGLDisplay dpy) {
 		return;
 	}
 	eglext.initialized = true;
-#define check_ext(name) eglext.has_##name = egl_has_extension(dpy, #name)
+#define check_ext(name)                                                                  \
+	eglext.has_##name = epoxy_has_egl_extension(dpy, #name);                         \
+	log_info("Extension " #name " - %s", eglext.has_##name ? "present" : "absent")
+
 	check_ext(EGL_EXT_buffer_age);
 	check_ext(EGL_EXT_create_context_robustness);
 	check_ext(EGL_KHR_image_pixmap);
@@ -472,16 +413,4 @@ void eglext_init(EGLDisplay dpy) {
 	check_ext(EGL_MESA_query_driver);
 #endif
 #undef check_ext
-
-	// Checking if the returned function pointer is NULL is not really necessary,
-	// or maybe not even useful, since eglGetProcAddress might always return
-	// something. We are doing it just for completeness' sake.
-
-#ifdef EGL_MESA_query_driver
-	eglGetDisplayDriverName =
-	    (PFNEGLGETDISPLAYDRIVERNAMEPROC)eglGetProcAddress("eglGetDisplayDriverName");
-	if (!eglGetDisplayDriverName) {
-		eglext.has_EGL_MESA_query_driver = false;
-	}
-#endif
 }

src/backend/gl/egl.h

@@ -1,10 +1,8 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
 #pragma once
-#include <EGL/egl.h>
-#include <EGL/eglext.h>
-#include <GL/gl.h>
-#include <GL/glext.h>
+#include <epoxy/egl.h>
+#include <epoxy/gl.h>
 #include <stdbool.h>
 #include <xcb/render.h>
 #include <xcb/xcb.h>
@@ -24,8 +22,4 @@ struct eglext_info {
 
 extern struct eglext_info eglext;
 
-#ifdef EGL_MESA_query_driver
-extern PFNEGLGETDISPLAYDRIVERNAMEPROC eglGetDisplayDriverName;
-#endif
-
 void eglext_init(EGLDisplay);

src/backend/gl/gl_common.c

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
-#include <GL/gl.h>
-#include <GL/glext.h>
+#include <epoxy/gl.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
@@ -185,7 +184,7 @@ void gl_destroy_window_shader(backend_t *backend_data attr_unused, void *shader)
  * @note In order to reduce number of textures which needs to be
  * allocated and deleted during this recursive render
  * we reuse the same two textures for render source and
- * destination simply by alterating between them.
+ * destination simply by alternating between them.
  * Unfortunately on first iteration source_texture might
  * be read-only. In this case we will select auxiliary_texture as
  * destination_texture in order not to touch that read-only source
@@ -253,7 +252,7 @@ _gl_average_texture_color(backend_t *base, GLuint source_texture, GLuint destina
 
 /*
  * @brief Builds a 1x1 texture which has color corresponding to the average of all
- * pixels of img by recursively rendering into texture of quorter the size (half
+ * pixels of img by recursively rendering into texture of quarter the size (half
  * width and half height).
  * Returned texture must not be deleted, since it's owned by the gl_image. It will be
  * deleted when the gl_image is released.
@@ -390,6 +389,10 @@ static void _gl_compose(backend_t *base, struct backend_image *img, GLuint targe
 	if (win_shader->uniform_tex >= 0) {
 		glUniform1i(win_shader->uniform_tex, 0);
 	}
+	if (win_shader->uniform_effective_size >= 0) {
+		glUniform2f(win_shader->uniform_effective_size, (float)img->ewidth,
+		            (float)img->eheight);
+	}
 	if (win_shader->uniform_dim >= 0) {
 		glUniform1f(win_shader->uniform_dim, (float)img->dim);
 	}
@@ -417,7 +420,7 @@ static void _gl_compose(backend_t *base, struct backend_image *img, GLuint targe
 	}
 
 	glUniform1i(win_shader->uniform_mask_tex, 2);
-	glUniform2f(win_shader->uniform_mask_offset, (float)mask_offset.x,
+	glUniform2f(win_shader->uniform_mask_offset, (float)mask_offset.x ,
 	            (float)mask_offset.y);
 	if (mask != NULL) {
 		glUniform1i(win_shader->uniform_mask_inverted, mask->color_inverted);
@@ -499,6 +502,7 @@ void x_rect_to_coords(int nrects, const rect_t *rects, coord_t image_dst,
 	image_dst.y = root_height - image_dst.y;
 	image_dst.y -= extent_height;
 
+
 	for (int i = 0; i < nrects; i++) {
 		// Y-flip. Note after this, crect.y1 > crect.y2
 		rect_t crect = rects[i];
@@ -548,11 +552,12 @@ void x_rect_to_coords(int nrects, const rect_t *rects, coord_t image_dst,
 }
 
 // TODO(yshui) make use of reg_visible
-void gl_compose(backend_t *base, void *image_data, coord_t image_dst, void *mask,
+void gl_compose(backend_t *base, image_handle image_data, coord_t image_dst, image_handle mask_,
                 coord_t mask_dst, const region_t *reg_tgt,
-                const region_t *reg_visible attr_unused) {
+                const region_t *reg_visible attr_unused, bool lerp) {
 	auto gd = (struct gl_data *)base;
-	struct backend_image *img = image_data;
+	auto img = (struct backend_image *)image_data;
+	auto mask = (struct backend_image *)mask_;
 	auto inner = (struct gl_texture *)img->inner;
 
 	// Painting
@@ -576,6 +581,14 @@ void gl_compose(backend_t *base, void *image_data, coord_t image_dst, void *mask
 	coord_t mask_offset = {.x = mask_dst.x - image_dst.x, .y = mask_dst.y - image_dst.y};
 	x_rect_to_coords(nrects, rects, image_dst, inner->height, inner->height,
 	                 gd->height, inner->y_inverted, coord, indices);
+
+	if (lerp) {
+		for (unsigned int i = 2; i < 16; i+=4) {
+			coord[i+0] = lerp_range(0, mask_offset.x, 0, inner->width, coord[i+0]);
+			coord[i+1] = lerp_range(0, mask_offset.y, 0, inner->height, coord[i+1]);
+		}
+	}
+
 	_gl_compose(base, img, gd->back_fbo, mask, mask_offset, coord, indices, nrects);
 
 	free(indices);
@@ -599,6 +612,7 @@ static bool gl_win_shader_from_stringv(const char **vshader_strv,
 	bind_uniform(ret, opacity);
 	bind_uniform(ret, invert_color);
 	bind_uniform(ret, tex);
+	bind_uniform(ret, effective_size);
 	bind_uniform(ret, dim);
 	bind_uniform(ret, brightness);
 	bind_uniform(ret, max_brightness);
@@ -705,7 +719,7 @@ void gl_fill(backend_t *base, struct color c, const region_t *clip) {
 	return _gl_fill(base, c, clip, gd->back_fbo, gd->height, true);
 }
 
-void *gl_make_mask(backend_t *base, geometry_t size, const region_t *reg) {
+image_handle gl_make_mask(backend_t *base, geometry_t size, const region_t *reg) {
 	auto tex = ccalloc(1, struct gl_texture);
 	auto img = default_new_backend_image(size.width, size.height);
 	tex->width = size.width;
@@ -736,7 +750,7 @@ void *gl_make_mask(backend_t *base, geometry_t size, const region_t *reg) {
 	glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
 	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 	glDeleteFramebuffers(1, &fbo);
-	return img;
+	return (image_handle)img;
 }
 
 static void gl_release_image_inner(backend_t *base, struct gl_texture *inner) {
@@ -752,8 +766,8 @@ static void gl_release_image_inner(backend_t *base, struct gl_texture *inner) {
 	gl_check_err();
 }
 
-void gl_release_image(backend_t *base, void *image_data) {
-	struct backend_image *wd = image_data;
+void gl_release_image(backend_t *base, image_handle image) {
+	auto wd = (struct backend_image *)image;
 	auto inner = (struct gl_texture *)wd->inner;
 	inner->refcount--;
 	assert(inner->refcount >= 0);
@@ -880,24 +894,35 @@ bool gl_init(struct gl_data *gd, session_t *ps) {
 	glUseProgram(0);
 
 	gd->dithered_present = ps->o.dithered_present;
+	gd->dummy_prog =
+	    gl_create_program_from_strv((const char *[]){present_vertex_shader, NULL},
+	                                (const char *[]){dummy_frag, NULL});
+	if (!gd->dummy_prog) {
+		log_error("Failed to create the dummy shader");
+		return false;
+	}
 	if (gd->dithered_present) {
 		gd->present_prog = gl_create_program_from_strv(
 		    (const char *[]){present_vertex_shader, NULL},
 		    (const char *[]){present_frag, dither_glsl, NULL});
 	} else {
-		gd->present_prog = gl_create_program_from_strv(
-		    (const char *[]){present_vertex_shader, NULL},
-		    (const char *[]){dummy_frag, NULL});
+		gd->present_prog = gd->dummy_prog;
 	}
 	if (!gd->present_prog) {
 		log_error("Failed to create the present shader");
 		return false;
 	}
-	pml = glGetUniformLocationChecked(gd->present_prog, "projection");
-	glUseProgram(gd->present_prog);
-	glUniform1i(glGetUniformLocationChecked(gd->present_prog, "tex"), 0);
+
+	pml = glGetUniformLocationChecked(gd->dummy_prog, "projection");
+	glUseProgram(gd->dummy_prog);
+	glUniform1i(glGetUniformLocationChecked(gd->dummy_prog, "tex"), 0);
 	glUniformMatrix4fv(pml, 1, false, projection_matrix[0]);
-	glUseProgram(0);
+	if (gd->present_prog != gd->dummy_prog) {
+		pml = glGetUniformLocationChecked(gd->present_prog, "projection");
+		glUseProgram(gd->present_prog);
+		glUniform1i(glGetUniformLocationChecked(gd->present_prog, "tex"), 0);
+		glUniformMatrix4fv(pml, 1, false, projection_matrix[0]);
+	}
 
 	gd->shadow_shader.prog =
 	    gl_create_program_from_str(present_vertex_shader, shadow_colorization_frag);
@@ -907,7 +932,6 @@ bool gl_init(struct gl_data *gd, session_t *ps) {
 	glUseProgram(gd->shadow_shader.prog);
 	glUniform1i(glGetUniformLocationChecked(gd->shadow_shader.prog, "tex"), 0);
 	glUniformMatrix4fv(pml, 1, false, projection_matrix[0]);
-	glUseProgram(0);
 	glBindFragDataLocation(gd->shadow_shader.prog, 0, "out_color");
 
 	gd->brightness_shader.prog =
@@ -920,6 +944,7 @@ bool gl_init(struct gl_data *gd, session_t *ps) {
 	glUseProgram(gd->brightness_shader.prog);
 	glUniform1i(glGetUniformLocationChecked(gd->brightness_shader.prog, "tex"), 0);
 	glUniformMatrix4fv(pml, 1, false, projection_matrix[0]);
+
 	glUseProgram(0);
 
 	// Set up the size and format of the back texture
@@ -956,8 +981,8 @@ bool gl_init(struct gl_data *gd, session_t *ps) {
 	} else {
 		gd->is_nvidia = false;
 	}
-	gd->has_robustness = gl_has_extension("GL_ARB_robustness");
-	gd->has_egl_image_storage = gl_has_extension("GL_EXT_EGL_image_storage");
+	gd->has_robustness = epoxy_has_gl_extension("GL_ARB_robustness");
+	gd->has_egl_image_storage = epoxy_has_gl_extension("GL_EXT_EGL_image_storage");
 	gl_check_err();
 
 	return true;
@@ -973,10 +998,25 @@ void gl_deinit(struct gl_data *gd) {
 		gl_destroy_window_shader(&gd->base, gd->default_shader);
 		gd->default_shader = NULL;
 	}
+	glDeleteProgram(gd->dummy_prog);
+	if (gd->present_prog != gd->dummy_prog) {
+		glDeleteProgram(gd->present_prog);
+	}
+	gd->dummy_prog = 0;
+	gd->present_prog = 0;
+
+	glDeleteProgram(gd->fill_shader.prog);
+	glDeleteProgram(gd->brightness_shader.prog);
+	glDeleteProgram(gd->shadow_shader.prog);
+	gd->fill_shader.prog = 0;
+	gd->brightness_shader.prog = 0;
+	gd->shadow_shader.prog = 0;
 
 	glDeleteTextures(1, &gd->default_mask_texture);
 	glDeleteTextures(1, &gd->back_texture);
 
+	glDeleteQueries(2, gd->frame_timing);
+
 	gl_check_err();
 }
 
@@ -1008,9 +1048,11 @@ static inline void gl_image_decouple(backend_t *base, struct backend_image *img)
 	auto new_tex = ccalloc(1, struct gl_texture);
 
 	new_tex->texture = gl_new_texture(GL_TEXTURE_2D);
-	new_tex->y_inverted = true;
+	new_tex->y_inverted = inner->y_inverted;
+	new_tex->has_alpha = inner->has_alpha;
 	new_tex->height = inner->height;
 	new_tex->width = inner->width;
+	new_tex->shader = inner->shader;
 	new_tex->refcount = 1;
 	new_tex->user_data = gd->decouple_texture_user_data(base, inner->user_data);
 
@@ -1019,8 +1061,7 @@ static inline void gl_image_decouple(backend_t *base, struct backend_image *img)
 	             GL_BGRA, GL_UNSIGNED_BYTE, NULL);
 	glBindTexture(GL_TEXTURE_2D, 0);
 
-	assert(gd->present_prog);
-	glUseProgram(gd->present_prog);
+	glUseProgram(gd->dummy_prog);
 	glBindTexture(GL_TEXTURE_2D, inner->texture);
 
 	GLuint fbo;
@@ -1190,9 +1231,9 @@ bool gl_last_render_time(backend_t *base, struct timespec *ts) {
 	return true;
 }
 
-bool gl_image_op(backend_t *base, enum image_operations op, void *image_data,
+bool gl_image_op(backend_t *base, enum image_operations op, image_handle image,
                  const region_t *reg_op, const region_t *reg_visible attr_unused, void *arg) {
-	struct backend_image *tex = image_data;
+	auto tex = (struct backend_image *)image;
 	switch (op) {
 	case IMAGE_OP_APPLY_ALPHA:
 		gl_image_decouple(base, tex);
@@ -1205,12 +1246,12 @@ bool gl_image_op(backend_t *base, enum image_operations op, void *image_data,
 }
 
 bool gl_set_image_property(backend_t *backend_data, enum image_properties prop,
-                           void *image_data, void *args) {
+                           image_handle image, void *args) {
 	if (prop != IMAGE_PROPERTY_CUSTOM_SHADER) {
-		return default_set_image_property(backend_data, prop, image_data, args);
+		return default_set_image_property(backend_data, prop, image, args);
 	}
 
-	struct backend_image *img = image_data;
+	auto img = (struct backend_image *)image;
 	auto inner = (struct gl_texture *)img->inner;
 	inner->shader = args;
 	return true;
@@ -1249,12 +1290,12 @@ void gl_destroy_shadow_context(backend_t *base attr_unused, struct backend_shado
 	free(ctx_);
 }
 
-void *gl_shadow_from_mask(backend_t *base, void *mask,
-                          struct backend_shadow_context *sctx, struct color color) {
+image_handle gl_shadow_from_mask(backend_t *base, image_handle mask_,
+                                 struct backend_shadow_context *sctx, struct color color) {
 	log_debug("Create shadow from mask");
 	auto gd = (struct gl_data *)base;
-	auto img = (struct backend_image *)mask;
-	auto inner = (struct gl_texture *)img->inner;
+	auto mask = (struct backend_image *)mask_;
+	auto inner = (struct gl_texture *)mask->inner;
 	auto gsctx = (struct gl_shadow_context *)sctx;
 	int radius = (int)gsctx->radius;
 
@@ -1284,7 +1325,7 @@ void *gl_shadow_from_mask(backend_t *base, void *mask,
 	glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
 	                       source_texture, 0);
 	glDrawBuffer(GL_COLOR_ATTACHMENT0);
-	if (img->color_inverted) {
+	if (mask->color_inverted) {
 		// If the mask is inverted, clear the source_texture to white, so the
 		// "outside" of the mask would be correct
 		glClearColor(1, 1, 1, 1);
@@ -1393,7 +1434,7 @@ void *gl_shadow_from_mask(backend_t *base, void *mask,
 	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 	glDeleteFramebuffers(1, &fbo);
 	gl_check_err();
-	return new_img;
+	return (image_handle)new_img;
 }
 
 enum device_status gl_device_status(backend_t *base) {

src/backend/gl/gl_common.h

@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
 #pragma once
-#include <GL/gl.h>
-#include <GL/glext.h>
+#include <epoxy/gl.h>
 #include <stdbool.h>
 #include <string.h>
 
 #include "backend/backend.h"
+#include "backend/backend_common.h"
 #include "log.h"
 #include "region.h"
 
@@ -29,12 +29,11 @@ static inline GLint glGetUniformLocationChecked(GLuint p, const char *name) {
 
 // Program and uniforms for window shader
 typedef struct {
-	UT_hash_handle hh;
-	uint32_t id;
 	GLuint prog;
 	GLint uniform_opacity;
 	GLint uniform_invert_color;
 	GLint uniform_tex;
+	GLint uniform_effective_size;
 	GLint uniform_dim;
 	GLint uniform_brightness;
 	GLint uniform_max_brightness;
@@ -77,7 +76,7 @@ typedef struct {
 	GLint color_loc;
 } gl_fill_shader_t;
 
-/// @brief Wrapper of a binded GL texture.
+/// @brief Wrapper of a bound GL texture.
 struct gl_texture {
 	int refcount;
 	bool has_alpha;
@@ -111,6 +110,7 @@ struct gl_data {
 	GLuint frame_timing[2];
 	int current_frame_timing;
 	GLuint present_prog;
+	GLuint dummy_prog;
 
 	bool dithered_present;
 
@@ -144,14 +144,14 @@ void *gl_create_window_shader(backend_t *backend_data, const char *source);
 void gl_destroy_window_shader(backend_t *backend_data, void *shader);
 uint64_t gl_get_shader_attributes(backend_t *backend_data, void *shader);
 bool gl_set_image_property(backend_t *backend_data, enum image_properties prop,
-                           void *image_data, void *args);
+                           image_handle image, void *args);
 bool gl_last_render_time(backend_t *backend_data, struct timespec *time);
 
 /**
  * @brief Render a region with texture data.
  */
-void gl_compose(backend_t *, void *image_data, coord_t image_dst, void *mask,
-                coord_t mask_dst, const region_t *reg_tgt, const region_t *reg_visible);
+void gl_compose(backend_t *, image_handle image_data, coord_t image_dst, image_handle mask_,
+                coord_t mask_dst, const region_t *reg_tgt, const region_t *reg_visible, bool lerp);
 
 void gl_resize(struct gl_data *, int width, int height);
 
@@ -160,32 +160,32 @@ void gl_deinit(struct gl_data *gd);
 
 GLuint gl_new_texture(GLenum target);
 
-bool gl_image_op(backend_t *base, enum image_operations op, void *image_data,
+bool gl_image_op(backend_t *base, enum image_operations op, image_handle image,
                  const region_t *reg_op, const region_t *reg_visible, void *arg);
 
-void gl_release_image(backend_t *base, void *image_data);
-void *gl_make_mask(backend_t *base, geometry_t size, const region_t *reg);
+void gl_release_image(backend_t *base, image_handle image);
+image_handle gl_make_mask(backend_t *base, geometry_t size, const region_t *reg);
 
-void *gl_clone(backend_t *base, const void *image_data, const region_t *reg_visible);
+image_handle gl_clone(backend_t *base, image_handle image, const region_t *reg_visible);
 
-bool gl_blur(backend_t *base, double opacity, void *ctx, void *mask, coord_t mask_dst,
-             const region_t *reg_blur, const region_t *reg_visible);
-bool gl_blur_impl(double opacity, struct gl_blur_context *bctx, void *mask, coord_t mask_dst,
-                  const region_t *reg_blur, const region_t *reg_visible attr_unused,
-                  GLuint source_texture, geometry_t source_size, GLuint target_fbo,
-                  GLuint default_mask, bool high_precision);
+bool gl_blur(backend_t *base, double opacity, void *ctx, image_handle mask,
+             coord_t mask_dst, const region_t *reg_blur, const region_t *reg_visible);
+bool gl_blur_impl(double opacity, struct gl_blur_context *bctx,
+                  struct backend_image *mask, coord_t mask_dst, const region_t *reg_blur,
+                  const region_t *reg_visible attr_unused, GLuint source_texture,
+                  geometry_t source_size, GLuint target_fbo, GLuint default_mask,
+                  bool high_precision);
 void *gl_create_blur_context(backend_t *base, enum blur_method, void *args);
 void gl_destroy_blur_context(backend_t *base, void *ctx);
 struct backend_shadow_context *gl_create_shadow_context(backend_t *base, double radius);
 void gl_destroy_shadow_context(backend_t *base attr_unused, struct backend_shadow_context *ctx);
-void *gl_shadow_from_mask(backend_t *base, void *mask,
-                          struct backend_shadow_context *sctx, struct color color);
+image_handle gl_shadow_from_mask(backend_t *base, image_handle mask,
+                                 struct backend_shadow_context *sctx, struct color color);
 void gl_get_blur_size(void *blur_context, int *width, int *height);
 
 void gl_fill(backend_t *base, struct color, const region_t *clip);
 
 void gl_present(backend_t *base, const region_t *);
-bool gl_read_pixel(backend_t *base, void *image_data, int x, int y, struct color *output);
 enum device_status gl_device_status(backend_t *base);
 
 /**
@@ -264,26 +264,6 @@ static inline bool gl_check_fb_complete_(const char *func, int line, GLenum fb)
 
 #define gl_check_fb_complete(fb) gl_check_fb_complete_(__func__, __LINE__, (fb))
 
-/**
- * Check if a GL extension exists.
- */
-static inline bool gl_has_extension(const char *ext) {
-	int nexts = 0;
-	glGetIntegerv(GL_NUM_EXTENSIONS, &nexts);
-	for (int i = 0; i < nexts || !nexts; i++) {
-		const char *exti = (const char *)glGetStringi(GL_EXTENSIONS, (GLuint)i);
-		if (exti == NULL) {
-			break;
-		}
-		if (strcmp(ext, exti) == 0) {
-			return true;
-		}
-	}
-	gl_clear_err();
-	log_info("Missing GL extension %s.", ext);
-	return false;
-}
-
 static const GLuint vert_coord_loc = 0;
 static const GLuint vert_in_texcoord_loc = 1;
 

src/backend/gl/glx.c

@@ -17,8 +17,10 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
+#include <uthash.h>
 #include <xcb/composite.h>
 #include <xcb/xcb.h>
+#include <xcb/xcb_aux.h>
 
 #include "backend/backend.h"
 #include "backend/backend_common.h"
@@ -44,6 +46,13 @@ struct _glx_data {
 	struct gl_data gl;
 	xcb_window_t target_win;
 	GLXContext ctx;
+	struct glx_fbconfig_cache *cached_fbconfigs;
+};
+
+struct glx_fbconfig_cache {
+	UT_hash_handle hh;
+	struct xvisual_info visual_info;
+	struct glx_fbconfig_info info;
 };
 
 #define glXGetFBConfigAttribChecked(a, b, attr, c)                                       \
@@ -54,9 +63,12 @@ struct _glx_data {
 		}                                                                        \
 	} while (0)
 
-struct glx_fbconfig_info *glx_find_fbconfig(struct x_connection *c, struct xvisual_info m) {
-	log_debug("Looking for FBConfig for RGBA%d%d%d%d, depth %d", m.red_size,
-	          m.blue_size, m.green_size, m.alpha_size, m.visual_depth);
+bool glx_find_fbconfig(struct x_connection *c, struct xvisual_info m,
+                       struct glx_fbconfig_info *info) {
+	log_debug("Looking for FBConfig for RGBA%d%d%d%d, depth: %d, visual id: %#x", m.red_size,
+	          m.blue_size, m.green_size, m.alpha_size, m.visual_depth, m.visual);
+
+	info->cfg = NULL;
 
 	int ncfg;
 	// clang-format off
@@ -114,7 +126,8 @@ struct glx_fbconfig_info *glx_find_fbconfig(struct x_connection *c, struct xvisu
 		int visual;
 		glXGetFBConfigAttribChecked(c->dpy, cfg[i], GLX_VISUAL_ID, &visual);
 		if (m.visual_depth != -1 &&
-		    x_get_visual_depth(c, (xcb_visualid_t)visual) != m.visual_depth) {
+		    xcb_aux_get_depth_of_visual(c->screen_info, (xcb_visualid_t)visual) !=
+		        m.visual_depth) {
 			// FBConfig and the correspondent X Visual might not have the same
 			// depth. (e.g. 32 bit FBConfig with a 24 bit Visual). This is
 			// quite common, seen in both open source and proprietary drivers.
@@ -143,16 +156,13 @@ struct glx_fbconfig_info *glx_find_fbconfig(struct x_connection *c, struct xvisu
 		min_cost = depthbuf + stencil + bufsize * (doublebuf + 1);
 	}
 	free(cfg);
-	if (!found) {
-		return NULL;
+	if (found) {
+		info->cfg = ret;
+		info->texture_tgts = texture_tgts;
+		info->texture_fmt = texture_fmt;
+		info->y_inverted = y_inverted;
 	}
-
-	auto info = cmalloc(struct glx_fbconfig_info);
-	info->cfg = ret;
-	info->texture_tgts = texture_tgts;
-	info->texture_fmt = texture_fmt;
-	info->y_inverted = y_inverted;
-	return info;
+	return found;
 }
 
 /**
@@ -197,6 +207,12 @@ void glx_deinit(backend_t *base) {
 		gd->ctx = 0;
 	}
 
+	struct glx_fbconfig_cache *cached_fbconfig = NULL, *tmp = NULL;
+	HASH_ITER(hh, gd->cached_fbconfigs, cached_fbconfig, tmp) {
+		HASH_DEL(gd->cached_fbconfigs, cached_fbconfig);
+		free(cached_fbconfig);
+	}
+
 	free(gd);
 }
 
@@ -364,9 +380,10 @@ end:
 	return &gd->gl.base;
 }
 
-static void *
+static image_handle
 glx_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, bool owned) {
 	struct _glx_pixmap *glxpixmap = NULL;
+	auto gd = (struct _glx_data *)base;
 	// Retrieve pixmap parameters, if they aren't provided
 	if (fmt.visual_depth > OPENGL_MAX_DEPTH) {
 		log_error("Requested depth %d higher than max possible depth %d.",
@@ -394,38 +411,52 @@ glx_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, b
 	wd->inner = (struct backend_image_inner_base *)inner;
 	free(r);
 
-	auto fbcfg = glx_find_fbconfig(base->c, fmt);
-	if (!fbcfg) {
-		log_error("Couldn't find FBConfig with requested visual %x", fmt.visual);
-		goto err;
+	struct glx_fbconfig_cache *cached_fbconfig = NULL;
+	HASH_FIND(hh, gd->cached_fbconfigs, &fmt, sizeof(fmt), cached_fbconfig);
+	if (!cached_fbconfig) {
+		struct glx_fbconfig_info fbconfig;
+		if (!glx_find_fbconfig(base->c, fmt, &fbconfig)) {
+			log_error("Couldn't find FBConfig with requested visual %#x",
+			          fmt.visual);
+			goto err;
+		}
+		cached_fbconfig = cmalloc(struct glx_fbconfig_cache);
+		cached_fbconfig->visual_info = fmt;
+		cached_fbconfig->info = fbconfig;
+		HASH_ADD(hh, gd->cached_fbconfigs, visual_info, sizeof(fmt), cached_fbconfig);
+	} else {
+		log_debug("Found cached FBConfig for RGBA%d%d%d%d, depth: %d, visual id: "
+		          "%#x",
+		          fmt.red_size, fmt.blue_size, fmt.green_size, fmt.alpha_size,
+		          fmt.visual_depth, fmt.visual);
 	}
+	struct glx_fbconfig_info *fbconfig = &cached_fbconfig->info;
 
 	// Choose a suitable texture target for our pixmap.
 	// Refer to GLX_EXT_texture_om_pixmap spec to see what are the mean
 	// of the bits in texture_tgts
-	if (!(fbcfg->texture_tgts & GLX_TEXTURE_2D_BIT_EXT)) {
+	if (!(fbconfig->texture_tgts & GLX_TEXTURE_2D_BIT_EXT)) {
 		log_error("Cannot bind pixmap to GL_TEXTURE_2D, giving up");
 		goto err;
 	}
 
 	log_debug("depth %d, rgba %d", fmt.visual_depth,
-	          (fbcfg->texture_fmt == GLX_TEXTURE_FORMAT_RGBA_EXT));
+	          (fbconfig->texture_fmt == GLX_TEXTURE_FORMAT_RGBA_EXT));
 
 	GLint attrs[] = {
 	    GLX_TEXTURE_FORMAT_EXT,
-	    fbcfg->texture_fmt,
+	    fbconfig->texture_fmt,
 	    GLX_TEXTURE_TARGET_EXT,
 	    GLX_TEXTURE_2D_EXT,
 	    0,
 	};
 
-	inner->y_inverted = fbcfg->y_inverted;
+	inner->y_inverted = fbconfig->y_inverted;
 
 	glxpixmap = cmalloc(struct _glx_pixmap);
 	glxpixmap->pixmap = pixmap;
-	glxpixmap->glpixmap = glXCreatePixmap(base->c->dpy, fbcfg->cfg, pixmap, attrs);
+	glxpixmap->glpixmap = glXCreatePixmap(base->c->dpy, fbconfig->cfg, pixmap, attrs);
 	glxpixmap->owned = owned;
-	free(fbcfg);
 
 	if (!glxpixmap->glpixmap) {
 		log_error("Failed to create glpixmap for pixmap %#010x", pixmap);
@@ -444,7 +475,7 @@ glx_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, b
 	glBindTexture(GL_TEXTURE_2D, 0);
 
 	gl_check_err();
-	return wd;
+	return (image_handle)wd;
 err:
 	if (glxpixmap && glxpixmap->glpixmap) {
 		glXDestroyPixmap(base->c->dpy, glxpixmap->glpixmap);
@@ -545,62 +576,17 @@ struct backend_operations glx_ops = {
     .max_buffer_age = 5,        // Why?
 };
 
-/**
- * Check if a GLX extension exists.
- */
-static inline bool glx_has_extension(Display *dpy, int screen, const char *ext) {
-	const char *glx_exts = glXQueryExtensionsString(dpy, screen);
-	if (!glx_exts) {
-		log_error("Failed get GLX extension list.");
-		return false;
-	}
-
-	auto inlen = strlen(ext);
-	const char *curr = glx_exts;
-	bool match = false;
-	while (curr && !match) {
-		const char *end = strchr(curr, ' ');
-		if (!end) {
-			// Last extension string
-			match = strcmp(ext, curr) == 0;
-		} else if (curr + inlen == end) {
-			// Length match, do match string
-			match = strncmp(ext, curr, (unsigned long)(end - curr)) == 0;
-		}
-		curr = end ? end + 1 : NULL;
-	}
-
-	if (!match) {
-		log_info("Missing GLX extension %s.", ext);
-	} else {
-		log_info("Found GLX extension %s.", ext);
-	}
-
-	return match;
-}
-
 struct glxext_info glxext = {0};
-PFNGLXGETVIDEOSYNCSGIPROC glXGetVideoSyncSGI;
-PFNGLXWAITVIDEOSYNCSGIPROC glXWaitVideoSyncSGI;
-PFNGLXGETSYNCVALUESOMLPROC glXGetSyncValuesOML;
-PFNGLXWAITFORMSCOMLPROC glXWaitForMscOML;
-PFNGLXSWAPINTERVALEXTPROC glXSwapIntervalEXT;
-PFNGLXSWAPINTERVALSGIPROC glXSwapIntervalSGI;
-PFNGLXSWAPINTERVALMESAPROC glXSwapIntervalMESA;
-PFNGLXBINDTEXIMAGEEXTPROC glXBindTexImageEXT;
-PFNGLXRELEASETEXIMAGEEXTPROC glXReleaseTexImageEXT;
-PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB;
-
-#ifdef GLX_MESA_query_renderer
-PFNGLXQUERYCURRENTRENDERERINTEGERMESAPROC glXQueryCurrentRendererIntegerMESA;
-#endif
 
 void glxext_init(Display *dpy, int screen) {
 	if (glxext.initialized) {
 		return;
 	}
 	glxext.initialized = true;
-#define check_ext(name) glxext.has_##name = glx_has_extension(dpy, screen, #name)
+#define check_ext(name)                                                                  \
+	glxext.has_##name = epoxy_has_glx_extension(dpy, screen, #name);                 \
+	log_info("Extension " #name " - %s", glxext.has_##name ? "present" : "absent")
+
 	check_ext(GLX_SGI_video_sync);
 	check_ext(GLX_SGI_swap_control);
 	check_ext(GLX_OML_sync_control);
@@ -614,36 +600,4 @@ void glxext_init(Display *dpy, int screen) {
 	check_ext(GLX_MESA_query_renderer);
 #endif
 #undef check_ext
-
-#define lookup(name) ((name) = (__typeof__(name))glXGetProcAddress((GLubyte *)#name))
-	// Checking if the returned function pointer is NULL is not really necessary,
-	// or maybe not even useful, since glXGetProcAddress might always return
-	// something. We are doing it just for completeness' sake.
-	if (!lookup(glXGetVideoSyncSGI) || !lookup(glXWaitVideoSyncSGI)) {
-		glxext.has_GLX_SGI_video_sync = false;
-	}
-	if (!lookup(glXSwapIntervalEXT)) {
-		glxext.has_GLX_EXT_swap_control = false;
-	}
-	if (!lookup(glXSwapIntervalMESA)) {
-		glxext.has_GLX_MESA_swap_control = false;
-	}
-	if (!lookup(glXSwapIntervalSGI)) {
-		glxext.has_GLX_SGI_swap_control = false;
-	}
-	if (!lookup(glXWaitForMscOML) || !lookup(glXGetSyncValuesOML)) {
-		glxext.has_GLX_OML_sync_control = false;
-	}
-	if (!lookup(glXBindTexImageEXT) || !lookup(glXReleaseTexImageEXT)) {
-		glxext.has_GLX_EXT_texture_from_pixmap = false;
-	}
-	if (!lookup(glXCreateContextAttribsARB)) {
-		glxext.has_GLX_ARB_create_context = false;
-	}
-#ifdef GLX_MESA_query_renderer
-	if (!lookup(glXQueryCurrentRendererIntegerMESA)) {
-		glxext.has_GLX_MESA_query_renderer = false;
-	}
-#endif
-#undef lookup
 }

src/backend/gl/glx.h

@@ -1,17 +1,9 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
 #pragma once
-#include <stdbool.h>
-// Older version of glx.h defines function prototypes for these extensions...
-// Rename them to avoid conflicts
-#define glXSwapIntervalMESA glXSwapIntervalMESA_
-#define glXBindTexImageEXT glXBindTexImageEXT_
-#define glXReleaseTexImageEXT glXReleaseTexImageEXT
-#include <GL/glx.h>
-#undef glXSwapIntervalMESA
-#undef glXBindTexImageEXT
-#undef glXReleaseTexImageEXT
 #include <X11/Xlib.h>
+#include <epoxy/glx.h>
+#include <stdbool.h>
 #include <xcb/render.h>
 #include <xcb/xcb.h>
 
@@ -27,21 +19,8 @@ struct glx_fbconfig_info {
 	int y_inverted;
 };
 
-/// The search criteria for glx_find_fbconfig
-struct glx_fbconfig_criteria {
-	/// Bit width of the red component
-	int red_size;
-	/// Bit width of the green component
-	int green_size;
-	/// Bit width of the blue component
-	int blue_size;
-	/// Bit width of the alpha component
-	int alpha_size;
-	/// The depth of X visual
-	int visual_depth;
-};
-
-struct glx_fbconfig_info *glx_find_fbconfig(struct x_connection *, struct xvisual_info);
+bool glx_find_fbconfig(struct x_connection *c, struct xvisual_info m,
+                       struct glx_fbconfig_info *info);
 
 struct glxext_info {
 	bool initialized;
@@ -59,19 +38,4 @@ struct glxext_info {
 
 extern struct glxext_info glxext;
 
-extern PFNGLXGETVIDEOSYNCSGIPROC glXGetVideoSyncSGI;
-extern PFNGLXWAITVIDEOSYNCSGIPROC glXWaitVideoSyncSGI;
-extern PFNGLXGETSYNCVALUESOMLPROC glXGetSyncValuesOML;
-extern PFNGLXWAITFORMSCOMLPROC glXWaitForMscOML;
-extern PFNGLXSWAPINTERVALEXTPROC glXSwapIntervalEXT;
-extern PFNGLXSWAPINTERVALSGIPROC glXSwapIntervalSGI;
-extern PFNGLXSWAPINTERVALMESAPROC glXSwapIntervalMESA;
-extern PFNGLXBINDTEXIMAGEEXTPROC glXBindTexImageEXT;
-extern PFNGLXRELEASETEXIMAGEEXTPROC glXReleaseTexImageEXT;
-extern PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB;
-
-#ifdef GLX_MESA_query_renderer
-extern PFNGLXQUERYCURRENTRENDERERINTEGERMESAPROC glXQueryCurrentRendererIntegerMESA;
-#endif
-
 void glxext_init(Display *, int screen);

src/backend/gl/shaders.c

@@ -97,6 +97,7 @@ const char win_shader_glsl[] = GLSL(330,
 	uniform bool invert_color;
 	in vec2 texcoord;
 	uniform sampler2D tex;
+	uniform vec2 effective_size;
 	uniform sampler2D brightness;
 	uniform float max_brightness;
 	// Signed distance field for rectangle center at (0, 0), with size of
@@ -130,7 +131,7 @@ const char win_shader_glsl[] = GLSL(330,
 		// Using mix() to avoid a branch here.
 		vec4 rim_color = mix(c, border_color, clamp(border_width, 0.0f, 1.0f));
 
-		vec2 outer_size = vec2(textureSize(tex, 0));
+		vec2 outer_size = effective_size;
 		vec2 inner_size = outer_size - vec2(corner_radius) * 2.0f;
 		float rect_distance = rectangle_sdf(texcoord - outer_size / 2.0f,
 		    inner_size / 2.0f) - corner_radius;
@@ -157,7 +158,8 @@ const char win_shader_default[] = GLSL(330,
 	uniform sampler2D tex;
 	vec4 default_post_processing(vec4 c);
 	vec4 window_shader() {
-		vec4 c = texelFetch(tex, ivec2(texcoord), 0);
+		vec2 texsize = textureSize(tex, 0);
+		vec4 c = texture2D(tex, texcoord / texsize, 0);
 		return default_post_processing(c);
 	}
 );

src/backend/xrender/xrender.c

@@ -14,6 +14,7 @@
 #include "backend/backend.h"
 #include "backend/backend_common.h"
 #include "common.h"
+#include "compiler.h"
 #include "config.h"
 #include "kernel.h"
 #include "log.h"
@@ -56,6 +57,10 @@ typedef struct _xrender_data {
 	int target_width, target_height;
 
 	xcb_special_event_t *present_event;
+
+	/// Cache an X region to avoid creating and destroying it every frame. A
+	/// workaround for yshui/picom#1166.
+	xcb_xfixes_region_t present_region;
 } xrender_data;
 
 struct _xrender_blur_context {
@@ -250,10 +255,16 @@ compose_impl(struct _xrender_data *xd, struct xrender_image *xrimg, coord_t dst,
 	}
 	if (((img->color_inverted || img->dim != 0) && has_alpha) || img->corner_radius != 0) {
 		// Apply image properties using a temporary image, because the source
-		// image is transparent. Otherwise the properties can be applied directly
-		// on the target image.
+		// image is transparent or will get transparent corners. Otherwise the
+		// properties can be applied directly on the target image.
+		// Also force a 32-bit ARGB visual for transparent corners, otherwise the
+		// corners become black.
+		auto visual =
+		    (img->corner_radius != 0 && inner->depth != 32)
+		        ? x_get_visual_for_standard(xd->base.c, XCB_PICT_STANDARD_ARGB_32)
+		        : inner->visual;
 		auto tmp_pict = x_create_picture_with_visual(
-		    xd->base.c, inner->width, inner->height, inner->visual, 0, NULL);
+		    xd->base.c, inner->width, inner->height, visual, 0, NULL);
 
 		// Set clip region translated to source coordinate
 		x_set_picture_clip_region(xd->base.c, tmp_pict, to_i16_checked(-dst.x),
@@ -349,10 +360,12 @@ compose_impl(struct _xrender_data *xd, struct xrender_image *xrimg, coord_t dst,
 	pixman_region32_fini(&reg);
 }
 
-static void compose(backend_t *base, void *img_data, coord_t dst, void *mask, coord_t mask_dst,
-                    const region_t *reg_paint, const region_t *reg_visible) {
+static void compose(backend_t *base, image_handle image_, coord_t dst, image_handle mask_,
+                    coord_t mask_dst, const region_t *reg_paint, const region_t *reg_visible, attr_unused bool lerp) {
 	struct _xrender_data *xd = (void *)base;
-	return compose_impl(xd, img_data, dst, mask, mask_dst, reg_paint, reg_visible,
+	auto image = (struct xrender_image *)image_;
+	auto mask = (struct xrender_image *)mask_;
+	return compose_impl(xd, image, dst, mask, mask_dst, reg_paint, reg_visible,
 	                    xd->back[2]);
 }
 
@@ -374,9 +387,10 @@ static void fill(backend_t *base, struct color c, const region_t *clip) {
 	                         .height = to_u16_checked(extent->y2 - extent->y1)}});
 }
 
-static bool blur(backend_t *backend_data, double opacity, void *ctx_, void *mask,
+static bool blur(backend_t *backend_data, double opacity, void *ctx_, image_handle mask_,
                  coord_t mask_dst, const region_t *reg_blur, const region_t *reg_visible) {
-	struct _xrender_blur_context *bctx = ctx_;
+	auto bctx = (struct _xrender_blur_context *)ctx_;
+	auto mask = (struct xrender_image *)mask_;
 	if (bctx->method == BLUR_METHOD_NONE) {
 		return true;
 	}
@@ -507,7 +521,7 @@ static bool blur(backend_t *backend_data, double opacity, void *ctx_, void *mask
 	return true;
 }
 
-static void *
+static image_handle
 bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, bool owned) {
 	xcb_generic_error_t *e;
 	auto r = xcb_get_geometry_reply(base->c->c, xcb_get_geometry(base->c->c, pixmap), &e);
@@ -542,7 +556,7 @@ bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, bool
 		free(img);
 		return NULL;
 	}
-	return img;
+	return (image_handle)img;
 }
 static void release_image_inner(backend_t *base, struct _xrender_image_data_inner *inner) {
 	x_free_picture(base->c, inner->pict);
@@ -566,13 +580,13 @@ release_rounded_corner_cache(backend_t *base, struct xrender_rounded_rectangle_c
 	}
 }
 
-static void release_image(backend_t *base, void *image) {
-	struct xrender_image *img = image;
+static void release_image(backend_t *base, image_handle image) {
+	auto img = (struct xrender_image *)image;
 	release_rounded_corner_cache(base, img->rounded_rectangle);
 	img->rounded_rectangle = NULL;
 	img->base.inner->refcount -= 1;
 	if (img->base.inner->refcount == 0) {
-		release_image_inner(base, (void *)img->base.inner);
+		release_image_inner(base, (struct _xrender_image_data_inner *)img->base.inner);
 	}
 	free(img);
 }
@@ -591,6 +605,7 @@ static void deinit(backend_t *backend_data) {
 			xcb_free_pixmap(xd->base.c->c, xd->back_pixmap[i]);
 		}
 	}
+	x_destroy_region(xd->base.c, xd->present_region);
 	if (xd->present_event) {
 		xcb_unregister_for_special_event(xd->base.c->c, xd->present_event);
 	}
@@ -618,16 +633,15 @@ static void present(backend_t *base, const region_t *region) {
 		                     XCB_NONE, xd->back[xd->curr_back], orig_x, orig_y, 0,
 		                     0, orig_x, orig_y, region_width, region_height);
 
-		auto xregion = x_create_region(base->c, region);
-
 		// Make sure we got reply from PresentPixmap before waiting for events,
 		// to avoid deadlock
 		auto e = xcb_request_check(
-		    base->c->c, xcb_present_pixmap_checked(
-		                    xd->base.c->c, xd->target_win,
-		                    xd->back_pixmap[xd->curr_back], 0, XCB_NONE, xregion, 0,
-		                    0, XCB_NONE, XCB_NONE, XCB_NONE, 0, 0, 0, 0, 0, NULL));
-		x_destroy_region(base->c, xregion);
+		    base->c->c,
+		    xcb_present_pixmap_checked(
+		        base->c->c, xd->target_win, xd->back_pixmap[xd->curr_back], 0, XCB_NONE,
+		        x_set_region(base->c, xd->present_region, region) ? xd->present_region
+		                                                          : XCB_NONE,
+		        0, 0, XCB_NONE, XCB_NONE, XCB_NONE, 0, 0, 0, 0, 0, NULL));
 		if (e) {
 			log_error("Failed to present pixmap");
 			free(e);
@@ -701,7 +715,7 @@ new_inner(backend_t *base, int w, int h, xcb_visualid_t visual, uint8_t depth) {
 	return new_inner;
 }
 
-static void *make_mask(backend_t *base, geometry_t size, const region_t *reg) {
+static image_handle make_mask(backend_t *base, geometry_t size, const region_t *reg) {
 	struct _xrender_data *xd = (void *)base;
 	// Give the mask a 1 pixel wide border to emulate the clamp to border behavior of
 	// OpenGL textures.
@@ -744,7 +758,7 @@ static void *make_mask(backend_t *base, geometry_t size, const region_t *reg) {
 	img->base.dim = 0;
 	img->base.inner = (struct backend_image_inner_base *)inner;
 	img->rounded_rectangle = NULL;
-	return img;
+	return (image_handle)img;
 }
 
 static bool decouple_image(backend_t *base, struct backend_image *img, const region_t *reg) {
@@ -772,10 +786,10 @@ static bool decouple_image(backend_t *base, struct backend_image *img, const reg
 	return true;
 }
 
-static bool image_op(backend_t *base, enum image_operations op, void *image,
+static bool image_op(backend_t *base, enum image_operations op, image_handle image,
                      const region_t *reg_op, const region_t *reg_visible, void *arg) {
 	struct _xrender_data *xd = (void *)base;
-	struct backend_image *img = image;
+	auto img = (struct backend_image *)image;
 	region_t reg;
 	double *dargs = arg;
 
@@ -923,6 +937,10 @@ static backend_t *backend_xrender_init(session_t *ps, xcb_window_t target) {
 		xd->vsync = false;
 	}
 
+	if (xd->vsync) {
+		xd->present_region = x_create_region(&ps->c, &ps->screen_reg);
+	}
+
 	// We might need to do double buffering for vsync, and buffer 0 and 1 are for
 	// double buffering.
 	int first_buffer_index = xd->vsync ? 0 : 2;
@@ -950,19 +968,19 @@ err:
 	return NULL;
 }
 
-void *clone_image(backend_t *base attr_unused, const void *image_data,
-                  const region_t *reg_visible attr_unused) {
+image_handle clone_image(backend_t *base attr_unused, image_handle image,
+                         const region_t *reg_visible attr_unused) {
 	auto new_img = ccalloc(1, struct xrender_image);
-	*new_img = *(struct xrender_image *)image_data;
+	*new_img = *(struct xrender_image *)image;
 	new_img->base.inner->refcount++;
 	if (new_img->rounded_rectangle) {
 		new_img->rounded_rectangle->refcount++;
 	}
-	return new_img;
+	return (image_handle)new_img;
 }
 
-static bool
-set_image_property(backend_t *base, enum image_properties op, void *image, void *args) {
+static bool set_image_property(backend_t *base, enum image_properties op,
+                               image_handle image, void *args) {
 	auto xrimg = (struct xrender_image *)image;
 	if (op == IMAGE_PROPERTY_CORNER_RADIUS &&
 	    ((double *)args)[0] != xrimg->base.corner_radius) {

src/c2.c

@@ -1047,7 +1047,7 @@ static bool c2_l_postprocess(session_t *ps, c2_l_t *pleaf) {
 
 	// Get target atom if it's not a predefined one
 	if (pleaf->predef == C2_L_PUNDEFINED) {
-		pleaf->tgtatom = get_atom(ps->atoms, pleaf->tgt);
+		pleaf->tgtatom = get_atom(ps->atoms, pleaf->tgt, ps->c.c);
 		if (!pleaf->tgtatom) {
 			log_error("Failed to get atom for target \"%s\".", pleaf->tgt);
 			return false;
@@ -1380,14 +1380,10 @@ static inline void c2_match_once_leaf(session_t *ps, const struct managed_win *w
 			case C2_L_PWIDTHB: predef_target = w->widthb; break;
 			case C2_L_PHEIGHTB: predef_target = w->heightb; break;
 			case C2_L_PBDW: predef_target = w->g.border_width; break;
-			case C2_L_PFULLSCREEN:
-				predef_target = win_is_fullscreen(ps, w);
-				break;
+			case C2_L_PFULLSCREEN: predef_target = w->is_fullscreen; break;
 			case C2_L_POVREDIR: predef_target = w->a.override_redirect; break;
 			case C2_L_PARGB: predef_target = win_has_alpha(w); break;
-			case C2_L_PFOCUSED:
-				predef_target = win_is_focused_raw(ps, w);
-				break;
+			case C2_L_PFOCUSED: predef_target = win_is_focused_raw(w); break;
 			case C2_L_PWMWIN: predef_target = w->wmwin; break;
 			case C2_L_PBSHAPED: predef_target = w->bounding_shaped; break;
 			case C2_L_PROUNDED: predef_target = w->rounded_corners; break;
@@ -1513,7 +1509,8 @@ static inline void c2_match_once_leaf(session_t *ps, const struct managed_win *w
 		else {
 			char **strlst = NULL;
 			int nstr = 0;
-			if (wid_get_text_prop(ps, wid, pleaf->tgtatom, &strlst, &nstr)) {
+			if (wid_get_text_prop(&ps->c, ps->atoms, wid, pleaf->tgtatom,
+			                      &strlst, &nstr)) {
 				if (pleaf->index < 0 && nstr > 0 && strlen(strlst[0]) > 0) {
 					ntargets = to_u32_checked(nstr);
 					targets = (const char **)strlst;

src/cache.c

@@ -1,95 +1,43 @@
 #include <uthash.h>
 
-#include "compiler.h"
-#include "utils.h"
 #include "cache.h"
 
-struct cache_entry {
-	char *key;
-	void *value;
-	UT_hash_handle hh;
-};
-
-struct cache {
-	cache_getter_t getter;
-	cache_free_t free;
-	void *user_data;
-	struct cache_entry *entries;
-};
-
-void cache_set(struct cache *c, const char *key, void *data) {
-	struct cache_entry *e = NULL;
+struct cache_handle *cache_get(struct cache *c, const char *key) {
+	struct cache_handle *e;
 	HASH_FIND_STR(c->entries, key, e);
-	CHECK(!e);
-
-	e = ccalloc(1, struct cache_entry);
-	e->key = strdup(key);
-	e->value = data;
-	HASH_ADD_STR(c->entries, key, e);
+	return e;
 }
 
-void *cache_get(struct cache *c, const char *key, int *err) {
-	struct cache_entry *e;
-	HASH_FIND_STR(c->entries, key, e);
-	if (e) {
-		return e->value;
+int cache_get_or_fetch(struct cache *c, const char *key, struct cache_handle **value,
+                       void *user_data, cache_getter_t getter) {
+	*value = cache_get(c, key);
+	if (*value) {
+		return 0;
 	}
 
-	int tmperr;
-	if (!err) {
-		err = &tmperr;
+	int err = getter(c, key, value, user_data);
+	assert(err <= 0);
+	if (err < 0) {
+		return err;
 	}
+	(*value)->key = strdup(key);
 
-	*err = 0;
-	e = ccalloc(1, struct cache_entry);
-	e->key = strdup(key);
-	e->value = c->getter(c->user_data, key, err);
-	if (*err) {
-		free(e->key);
-		free(e);
-		return NULL;
-	}
-
-	HASH_ADD_STR(c->entries, key, e);
-	return e->value;
+	HASH_ADD_STR(c->entries, key, *value);
+	return 1;
 }
 
-static inline void _cache_invalidate(struct cache *c, struct cache_entry *e) {
-	if (c->free) {
-		c->free(c->user_data, e->value);
-	}
+static inline void
+cache_invalidate_impl(struct cache *c, struct cache_handle *e, cache_free_t free_fn) {
 	free(e->key);
 	HASH_DEL(c->entries, e);
-	free(e);
-}
-
-void cache_invalidate(struct cache *c, const char *key) {
-	struct cache_entry *e;
-	HASH_FIND_STR(c->entries, key, e);
-
-	if (e) {
-		_cache_invalidate(c, e);
+	if (free_fn) {
+		free_fn(c, e);
 	}
 }
 
-void cache_invalidate_all(struct cache *c) {
-	struct cache_entry *e, *tmpe;
+void cache_invalidate_all(struct cache *c, cache_free_t free_fn) {
+	struct cache_handle *e, *tmpe;
 	HASH_ITER(hh, c->entries, e, tmpe) {
-		_cache_invalidate(c, e);
+		cache_invalidate_impl(c, e, free_fn);
 	}
 }
-
-void *cache_free(struct cache *c) {
-	void *ret = c->user_data;
-	cache_invalidate_all(c);
-	free(c);
-	return ret;
-}
-
-struct cache *new_cache(void *ud, cache_getter_t getter, cache_free_t f) {
-	auto c = ccalloc(1, struct cache);
-	c->user_data = ud;
-	c->getter = getter;
-	c->free = f;
-	return c;
-}

src/cache.h

@@ -1,32 +1,43 @@
 #pragma once
 
+#include <uthash.h>
+#include "utils.h"
+
+#define cache_entry(ptr, type, member) container_of(ptr, type, member)
+
 struct cache;
+struct cache_handle;
 
-typedef void *(*cache_getter_t)(void *user_data, const char *key, int *err);
-typedef void (*cache_free_t)(void *user_data, void *data);
+/// User-provided function to fetch a value for the cache, when it's not present.
+/// Should return 0 if the value is fetched successfully, and a negative number if the
+/// value cannot be fetched. Getter doesn't need to initialize fields of `struct
+/// cache_handle`.
+typedef int (*cache_getter_t)(struct cache *, const char *key,
+                              struct cache_handle **value, void *user_data);
+typedef void (*cache_free_t)(struct cache *, struct cache_handle *value);
 
-/// Create a cache with `getter`, and a free function `f` which is used to free the cache
-/// value when they are invalidated.
-///
-/// `user_data` will be passed to `getter` and `f` when they are called.
-struct cache *new_cache(void *user_data, cache_getter_t getter, cache_free_t f);
+struct cache {
+	struct cache_handle *entries;
+};
 
-/// Fetch a value from the cache. If the value doesn't present in the cache yet, the
+static const struct cache CACHE_INIT = {NULL};
+
+struct cache_handle {
+	char *key;
+	UT_hash_handle hh;
+};
+
+/// Get a value from the cache. If the value doesn't present in the cache yet, the
 /// getter will be called, and the returned value will be stored into the cache.
-void *cache_get(struct cache *, const char *key, int *err);
+/// Returns 0 if the value is already present in the cache, 1 if the value is fetched
+/// successfully, and a negative number if the value cannot be fetched.
+int cache_get_or_fetch(struct cache *, const char *key, struct cache_handle **value,
+                       void *user_data, cache_getter_t getter);
 
-/// Invalidate a value in the cache.
-void cache_invalidate(struct cache *, const char *key);
+/// Get a value from the cache. If the value doesn't present in the cache, NULL will be
+/// returned.
+struct cache_handle *cache_get(struct cache *, const char *key);
 
-/// Invalidate all values in the cache.
-void cache_invalidate_all(struct cache *);
-
-/// Invalidate all values in the cache and free it. Returns the user data passed to
-/// `new_cache`
-void *cache_free(struct cache *);
-
-/// Insert a key-value pair into the cache. Only used for internal testing. Takes
-/// ownership of `data`
-///
-/// If `key` already exists in the cache, this function will abort the program.
-void cache_set(struct cache *c, const char *key, void *data);
+/// Invalidate all values in the cache. After this call, `struct cache` holds no allocated
+/// memory, and can be discarded.
+void cache_invalidate_all(struct cache *, cache_free_t free_fn);

src/common.h

@@ -139,12 +139,15 @@ typedef struct session {
 	// === Event handlers ===
 	/// ev_io for X connection
 	ev_io xiow;
-	/// Timer for checking DPMS power level
-	ev_timer dpms_check_timer;
 	/// Timeout for delayed unredirection.
 	ev_timer unredir_timer;
 	/// Timer for fading
 	ev_timer fade_timer;
+	/// Timer for animations
+	ev_timer animation_timer;
+	/// Use an ev_idle callback for drawing
+	/// So we only start drawing when events are processed
+	ev_idle draw_idle;
 	/// Use an ev_timer callback for drawing
 	ev_timer draw_timer;
 	/// Called every time we have timeouts or new data on socket,
@@ -177,7 +180,6 @@ typedef struct session {
 	bool server_grabbed;
 	/// Width of root window.
 	int root_width;
-	/// Height of root window.
 	int root_height;
 	/// X Composite overlay window.
 	xcb_window_t overlay;
@@ -188,7 +190,7 @@ typedef struct session {
 	/// Picture of the root window background.
 	paint_t root_tile_paint;
 	/// The backend data the root pixmap bound to
-	void *root_image;
+	image_handle root_image;
 	/// A region of the size of the screen.
 	region_t screen_reg;
 	/// Picture of root window. Destination of painting in no-DBE painting
@@ -206,7 +208,7 @@ typedef struct session {
 	/// Custom GLX program used for painting window.
 	// XXX should be in struct glx_session
 	glx_prog_main_t glx_prog_win;
-	struct glx_fbconfig_info *argb_fbconfig;
+	struct glx_fbconfig_info argb_fbconfig;
 #endif
 	/// Sync fence to sync draw operations
 	xcb_sync_fence_t sync_fence;
@@ -214,26 +216,19 @@ typedef struct session {
 	bool first_frame;
 	/// Whether screen has been turned off
 	bool screen_is_off;
-	/// Event context for X Present extension.
-	uint32_t present_event_id;
-	xcb_special_event_t *present_event;
 	/// When last MSC event happened, in useconds.
 	uint64_t last_msc_instant;
 	/// The last MSC number
 	uint64_t last_msc;
-	/// When the currently rendered frame will be displayed.
-	/// 0 means there is no pending frame.
-	uint64_t target_msc;
 	/// The delay between when the last frame was scheduled to be rendered, and when
 	/// the render actually started.
 	uint64_t last_schedule_delay;
 	/// When do we want our next frame to start rendering.
 	uint64_t next_render;
-	/// Did we actually render the last frame. Sometimes redraw will be scheduled only
-	/// to find out nothing has changed. In which case this will be set to false.
-	bool did_render;
 	/// Whether we can perform frame pacing.
 	bool frame_pacing;
+	/// Vblank event scheduler
+	struct vblank_scheduler *vblank_scheduler;
 
 	/// Render statistics
 	struct render_statistics render_stats;
@@ -245,8 +240,18 @@ typedef struct session {
 	options_t o;
 	/// Whether we have hit unredirection timeout.
 	bool tmout_unredir_hit;
-	/// Whether we need to redraw the screen
-	bool redraw_needed;
+	/// If the backend is busy. This means two things:
+	/// Either the backend is currently rendering a frame, or a frame has been
+	/// rendered but has yet to be presented. In either case, we should not start
+	/// another render right now. As if we start issuing rendering commands now, we
+	/// will have to wait for either the current render to finish, or the current
+	/// back buffer to become available again. In either case, we will be wasting
+	/// time.
+	bool backend_busy;
+	/// Whether a render is queued. This generally means there are pending updates
+	/// to the screen that's neither included in the current render, nor on the
+	/// screen.
+	bool render_queued;
 
 	/// Cache a xfixes region so we don't need to allocate it every time.
 	/// A workaround for yshui/picom#301
@@ -263,11 +268,18 @@ typedef struct session {
 	xcb_render_picture_t *alpha_picts;
 	/// Time of last fading. In milliseconds.
 	long long fade_time;
+	/// Time of last window animation step. In milliseconds.
+	long animation_time; // TODO(dccsillag) turn into `long long`, like fade_time
+	/// Head pointer of the error ignore linked list.
+	pending_reply_t *pending_reply_head;
+	/// Pointer to the <code>next</code> member of tail element of the error
+	/// ignore linked list.
+	pending_reply_t **pending_reply_tail;
 	// Cached blur convolution kernels.
 	struct x_convolution_kernel **blur_kerns_cache;
 	/// If we should quit
 	bool quit : 1;
-	// TODO(yshui) use separate flags for dfferent kinds of updates so we don't
+	// TODO(yshui) use separate flags for different kinds of updates so we don't
 	// waste our time.
 	/// Whether there are pending updates, like window creation, etc.
 	bool pending_updates : 1;

src/compiler.h

@@ -52,7 +52,7 @@
 #else
 # define attr_warn_unused_result
 #endif
-// An alias for conveninence
+// An alias for convenience
 #define must_use attr_warn_unused_result
 
 #if __has_attribute(nonnull)
@@ -105,9 +105,9 @@
 
 #ifndef unreachable
 # if defined(__GNUC__) || defined(__clang__)
-#  define unreachable() __builtin_unreachable()
+#  define unreachable() assert(false); __builtin_unreachable()
 # else
-#  define unreachable() do {} while(0)
+#  define unreachable() assert(false); do {} while(0)
 # endif
 #endif
 

src/config.c

@@ -8,6 +8,8 @@
 #include <limits.h>
 #include <math.h>
 #include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -41,10 +43,7 @@ const char *xdg_config_home(void) {
 			return NULL;
 		}
 
-		xdgh = cvalloc(strlen(home) + strlen(default_dir) + 1);
-
-		strcpy(xdgh, home);
-		strcat(xdgh, default_dir);
+		xdgh = mstrjoin(home, default_dir);
 	} else {
 		xdgh = strdup(xdgh);
 	}
@@ -561,7 +560,7 @@ static char *locate_auxiliary_file_at(const char *base, const char *scope, const
 }
 
 /**
- * Get a path of an auxiliary file to read, could be a shader file, or any supplimenrary
+ * Get a path of an auxiliary file to read, could be a shader file, or any supplementary
  * file.
  *
  * Follows the XDG specification to search for the shader file in configuration locations.
@@ -596,15 +595,17 @@ char *locate_auxiliary_file(const char *scope, const char *path, const char *inc
 	// Fall back to searching in user config directory
 	scoped_charp picom_scope = mstrjoin("/picom/", scope);
 	scoped_charp config_home = (char *)xdg_config_home();
-	char *ret = locate_auxiliary_file_at(config_home, picom_scope, path);
-	if (ret) {
-		return ret;
+	if (config_home) {
+		char *ret = locate_auxiliary_file_at(config_home, picom_scope, path);
+		if (ret) {
+			return ret;
+		}
 	}
 
 	// Fall back to searching in system config directory
 	auto config_dirs = xdg_config_dirs();
 	for (int i = 0; config_dirs[i]; i++) {
-		ret = locate_auxiliary_file_at(config_dirs[i], picom_scope, path);
+		char *ret = locate_auxiliary_file_at(config_dirs[i], picom_scope, path);
 		if (ret) {
 			free(config_dirs);
 			return ret;
@@ -612,7 +613,83 @@ char *locate_auxiliary_file(const char *scope, const char *path, const char *inc
 	}
 	free(config_dirs);
 
-	return ret;
+	return NULL;
+}
+
+struct debug_options_entry {
+	const char *name;
+	const char **choices;
+	size_t offset;
+};
+
+// clang-format off
+const char *vblank_scheduler_str[] = {
+	[VBLANK_SCHEDULER_PRESENT] = "present",
+	[VBLANK_SCHEDULER_SGI_VIDEO_SYNC] = "sgi_video_sync",
+	[LAST_VBLANK_SCHEDULER] = NULL
+};
+static const struct debug_options_entry debug_options_entries[] = {
+    {"smart_frame_pacing", NULL,                 offsetof(struct debug_options, smart_frame_pacing)},
+    {"force_vblank_sched", vblank_scheduler_str, offsetof(struct debug_options, force_vblank_scheduler)},
+};
+// clang-format on
+
+void parse_debug_option_single(char *setting, struct debug_options *debug_options) {
+	char *equal = strchr(setting, '=');
+	size_t name_len = equal ? (size_t)(equal - setting) : strlen(setting);
+	for (size_t i = 0; i < ARR_SIZE(debug_options_entries); i++) {
+		if (strncmp(setting, debug_options_entries[i].name, name_len) != 0) {
+			continue;
+		}
+		if (debug_options_entries[i].name[name_len] != '\0') {
+			continue;
+		}
+		auto value = (int *)((void *)debug_options + debug_options_entries[i].offset);
+		if (equal) {
+			const char *const arg = equal + 1;
+			if (debug_options_entries[i].choices != NULL) {
+				for (size_t j = 0; debug_options_entries[i].choices[j]; j++) {
+					if (strcmp(arg, debug_options_entries[i].choices[j]) ==
+					    0) {
+						*value = (int)j;
+						return;
+					}
+				}
+			}
+			if (!parse_int(arg, value)) {
+				log_error("Invalid value for debug option %s: %s, it "
+				          "will be ignored.",
+				          debug_options_entries[i].name, arg);
+			}
+		} else if (debug_options_entries[i].choices == NULL) {
+			*value = 1;
+		} else {
+			log_error(
+			    "Missing value for debug option %s, it will be ignored.", setting);
+		}
+		return;
+	}
+	log_error("Invalid debug option: %s", setting);
+}
+
+/// Parse debug options from environment variable `PICOM_DEBUG`.
+void parse_debug_options(struct debug_options *debug_options) {
+	const char *debug = getenv("PICOM_DEBUG");
+	const struct debug_options default_debug_options = {
+	    .force_vblank_scheduler = LAST_VBLANK_SCHEDULER,
+	};
+
+	*debug_options = default_debug_options;
+	if (!debug) {
+		return;
+	}
+
+	scoped_charp debug_copy = strdup(debug);
+	char *tmp, *needle = strtok_r(debug_copy, ";", &tmp);
+	while (needle) {
+		parse_debug_option_single(needle, debug_options);
+		needle = strtok_r(NULL, ";", &tmp);
+	}
 }
 
 /**
@@ -719,6 +796,10 @@ void set_default_winopts(options_t *opt, win_option_mask_t *mask, bool shadow_en
 			// opacity logic is complicated, and needs an "unset" state
 			opt->wintype_option[i].opacity = NAN;
 		}
+		if (!mask[i].animation) {
+			mask[i].animation = OPEN_WINDOW_ANIMATION_INVALID;
+			opt->wintype_option[i].animation = OPEN_WINDOW_ANIMATION_INVALID;
+		}
 		if (!mask[i].clip_shadow_above) {
 			mask[i].clip_shadow_above = true;
 			opt->wintype_option[i].clip_shadow_above = false;
@@ -726,6 +807,40 @@ void set_default_winopts(options_t *opt, win_option_mask_t *mask, bool shadow_en
 	}
 }
 
+enum open_window_animation parse_open_window_animation(const char *src) {
+	if (strcmp(src, "none") == 0) {
+		return OPEN_WINDOW_ANIMATION_NONE;
+	} else if (strcmp(src, "fly-in") == 0) {
+		return OPEN_WINDOW_ANIMATION_FLYIN;
+	} else if (strcmp(src, "zoom") == 0) {
+		return OPEN_WINDOW_ANIMATION_ZOOM;
+	} else if (strcmp(src, "slide-up") == 0) {
+		return OPEN_WINDOW_ANIMATION_SLIDE_UP;
+	} else if (strcmp(src, "slide-down") == 0) {
+		return OPEN_WINDOW_ANIMATION_SLIDE_DOWN;
+	} else if (strcmp(src, "slide-left") == 0) {
+		return OPEN_WINDOW_ANIMATION_SLIDE_LEFT;
+	} else if (strcmp(src, "slide-right") == 0) {
+		return OPEN_WINDOW_ANIMATION_SLIDE_RIGHT;
+	} else if (strcmp(src, "slide-out") == 0) {
+        return OPEN_WINDOW_ANIMATION_SLIDE_OUT;
+        } else if (strcmp(src, "slide-in") == 0) {
+        return OPEN_WINDOW_ANIMATION_SLIDE_IN;
+        } else if (strcmp(src, "slide-out-center") == 0) {
+            return OPEN_WINDOW_ANIMATION_SLIDE_OUT_CENTER;
+        } else if (strcmp(src, "slide-in-center") == 0) {
+            return OPEN_WINDOW_ANIMATION_SLIDE_IN_CENTER;
+        } else if (strcmp(src, "minimize") == 0 || strcmp(src, "maximize") == 0) {
+            return OPEN_WINDOW_ANIMATION_MINIMIZE;
+        } else if (strcmp(src, "squeeze") == 0) {
+            return OPEN_WINDOW_ANIMATION_SQUEEZE;
+        } else if (strcmp(src, "squeeze-bottom") == 0) {
+            return OPEN_WINDOW_ANIMATION_SQUEEZE_BOTTOM;
+        }
+
+	return OPEN_WINDOW_ANIMATION_INVALID;
+}
+
 char *parse_config(options_t *opt, const char *config_file, bool *shadow_enable,
                    bool *fading_enable, bool *hasneg, win_option_mask_t *winopt_mask) {
 	// clang-format off
@@ -771,6 +886,18 @@ char *parse_config(options_t *opt, const char *config_file, bool *shadow_enable,
 	    .no_fading_destroyed_argb = false,
 	    .fade_blacklist = NULL,
 
+	    .animations = false,
+	    .animation_for_open_window = OPEN_WINDOW_ANIMATION_NONE,
+	    .animation_for_transient_window = OPEN_WINDOW_ANIMATION_NONE,
+        .animation_for_unmap_window = OPEN_WINDOW_ANIMATION_NONE,
+        .animation_for_next_tag = OPEN_WINDOW_ANIMATION_NONE,
+        .animation_for_prev_tag = OPEN_WINDOW_ANIMATION_NONE,
+	    .animation_stiffness = 200.0,
+	    .animation_stiffness_tag_change = 200.0,
+	    .animation_window_mass = 1.0,
+	    .animation_dampening = 25,
+	    .animation_clamping = true,
+
 	    .inactive_opacity = 1.0,
 	    .inactive_opacity_override = false,
 	    .active_opacity = 1.0,
@@ -802,7 +929,8 @@ char *parse_config(options_t *opt, const char *config_file, bool *shadow_enable,
 
 	    .track_leader = false,
 
-	    .rounded_corners_blacklist = NULL
+	    .rounded_corners_blacklist = NULL,
+	    .animation_blacklist = NULL
 	};
 	// clang-format on
 
@@ -817,5 +945,6 @@ char *parse_config(options_t *opt, const char *config_file, bool *shadow_enable,
 	(void)hasneg;
 	(void)winopt_mask;
 #endif
+	parse_debug_options(&opt->debug_options);
 	return ret;
 }

src/config.h

@@ -40,6 +40,24 @@ enum backend {
 	NUM_BKEND,
 };
 
+enum open_window_animation {
+	OPEN_WINDOW_ANIMATION_NONE = 0,
+	OPEN_WINDOW_ANIMATION_FLYIN,
+	OPEN_WINDOW_ANIMATION_SLIDE_UP,
+	OPEN_WINDOW_ANIMATION_SLIDE_DOWN,
+	OPEN_WINDOW_ANIMATION_SLIDE_LEFT,
+	OPEN_WINDOW_ANIMATION_SLIDE_RIGHT,
+	OPEN_WINDOW_ANIMATION_SLIDE_IN,
+	OPEN_WINDOW_ANIMATION_SLIDE_OUT,
+	OPEN_WINDOW_ANIMATION_SLIDE_IN_CENTER,
+	OPEN_WINDOW_ANIMATION_SLIDE_OUT_CENTER,
+	OPEN_WINDOW_ANIMATION_ZOOM,
+	OPEN_WINDOW_ANIMATION_MINIMIZE,
+	OPEN_WINDOW_ANIMATION_SQUEEZE,
+	OPEN_WINDOW_ANIMATION_SQUEEZE_BOTTOM,
+	OPEN_WINDOW_ANIMATION_INVALID,
+};
+
 typedef struct win_option_mask {
 	bool shadow : 1;
 	bool fade : 1;
@@ -49,6 +67,7 @@ typedef struct win_option_mask {
 	bool redir_ignore : 1;
 	bool opacity : 1;
 	bool clip_shadow_above : 1;
+	enum open_window_animation animation;
 } win_option_mask_t;
 
 typedef struct win_option {
@@ -60,6 +79,7 @@ typedef struct win_option {
 	bool redir_ignore;
 	double opacity;
 	bool clip_shadow_above;
+	enum open_window_animation animation;
 } win_option_t;
 
 enum blur_method {
@@ -73,6 +93,27 @@ enum blur_method {
 
 typedef struct _c2_lptr c2_lptr_t;
 
+enum vblank_scheduler_type {
+	/// X Present extension based vblank events
+	VBLANK_SCHEDULER_PRESENT,
+	/// GLX_SGI_video_sync based vblank events
+	VBLANK_SCHEDULER_SGI_VIDEO_SYNC,
+	/// An invalid scheduler, served as a scheduler count, and
+	/// as a sentinel value.
+	LAST_VBLANK_SCHEDULER,
+};
+
+extern const char *vblank_scheduler_str[];
+
+/// Internal, private options for debugging and development use.
+struct debug_options {
+	/// Try to reduce frame latency by using vblank interval and render time
+	/// estimates. Right now it's not working well across drivers.
+	int smart_frame_pacing;
+	/// Override the vblank scheduler chosen by the compositor.
+	int force_vblank_scheduler;
+};
+
 /// Structure representing all options.
 typedef struct options {
 	// === Debugging ===
@@ -174,6 +215,33 @@ typedef struct options {
 	/// Fading blacklist. A linked list of conditions.
 	c2_lptr_t *fade_blacklist;
 
+	// === Animations ===
+	/// Whether to do window animations
+	bool animations;
+	/// Which animation to run when opening a window
+	enum open_window_animation animation_for_open_window;
+	/// Which animation to run when opening a transient window
+	enum open_window_animation animation_for_transient_window;
+	/// Which animation to run when unmapping a window
+	enum open_window_animation animation_for_unmap_window;
+	/// Which animation to run when swapping to new tag
+	enum open_window_animation animation_for_next_tag;
+	/// Which animation to run for old tag
+	enum open_window_animation animation_for_prev_tag;
+	/// Spring stiffness for animation
+	double animation_stiffness;
+	/// Spring stiffness for current tag animation
+	double animation_stiffness_tag_change;
+	/// Window mass for animation
+	double animation_window_mass;
+	/// Animation dampening
+	double animation_dampening;
+	/// Whether to clamp animations
+	bool animation_clamping;
+	/// Animation blacklist. A linked list of conditions.
+	c2_lptr_t *animation_blacklist;
+	/// TODO: open/close animations
+
 	// === Opacity ===
 	/// Default opacity for inactive windows.
 	/// 32-bit integer with the format of _NET_WM_WINDOW_OPACITY.
@@ -257,11 +325,20 @@ typedef struct options {
 	// Make transparent windows clip other windows, instead of blending on top of
 	// them
 	bool transparent_clipping;
+
+	// Enable fading for next tag
+	bool enable_fading_next_tag;
+
+	// Enable fading for prev tag
+	bool enable_fading_prev_tag;
+
 	/// A list of conditions of windows to which transparent clipping
 	/// should not apply
 	c2_lptr_t *transparent_clipping_blacklist;
 
 	bool dithered_present;
+
+	struct debug_options debug_options;
 } options_t;
 
 extern const char *const BACKEND_STRS[NUM_BKEND + 1];
@@ -275,6 +352,7 @@ bool must_use parse_rule_window_shader(c2_lptr_t **, const char *, const char *)
 char *must_use locate_auxiliary_file(const char *scope, const char *path,
                                      const char *include_dir);
 enum blur_method must_use parse_blur_method(const char *src);
+enum open_window_animation must_use parse_open_window_animation(const char *src);
 
 /**
  * Add a pattern to a condition linked list.
@@ -288,7 +366,7 @@ char **xdg_config_dirs(void);
 /// Parse a configuration file
 /// Returns the actually config_file name used, allocated on heap
 /// Outputs:
-///   shadow_enable = whether shaodw is enabled globally
+///   shadow_enable = whether shadow is enabled globally
 ///   fading_enable = whether fading is enabled globally
 ///   win_option_mask = whether option overrides for specific window type is set for given
 ///                     options

src/config_libconfig.c

@@ -81,17 +81,19 @@ FILE *open_config_file(const char *cpath, char **ppath) {
 
 	// First search for config file in user config directory
 	auto config_home = xdg_config_home();
-	auto ret = open_config_file_at(config_home, ppath);
-	free((void *)config_home);
-	if (ret) {
-		return ret;
+	if (config_home) {
+		auto ret = open_config_file_at(config_home, ppath);
+		free((void *)config_home);
+		if (ret) {
+			return ret;
+		}
 	}
 
 	// Fall back to legacy config file in user home directory
 	const char *home = getenv("HOME");
 	if (home && strlen(home)) {
 		auto path = mstrjoin(home, config_filename_legacy);
-		ret = fopen(path, "r");
+		auto ret = fopen(path, "r");
 		if (ret && ppath) {
 			*ppath = path;
 		} else {
@@ -105,7 +107,7 @@ FILE *open_config_file(const char *cpath, char **ppath) {
 	// Fall back to config file in system config directory
 	auto config_dirs = xdg_config_dirs();
 	for (int i = 0; config_dirs[i]; i++) {
-		ret = open_config_file_at(config_dirs[i], ppath);
+		auto ret = open_config_file_at(config_dirs[i], ppath);
 		if (ret) {
 			free(config_dirs);
 			return ret;
@@ -262,6 +264,15 @@ static inline void parse_wintype_config(const config_t *cfg, const char *member_
 			o->clip_shadow_above = ival;
 			mask->clip_shadow_above = true;
 		}
+        const char *sval = NULL;
+		if (config_setting_lookup_string(setting, "animation", &sval)) {
+			enum open_window_animation animation = parse_open_window_animation(sval);
+			if (animation >= OPEN_WINDOW_ANIMATION_INVALID)
+				animation = OPEN_WINDOW_ANIMATION_NONE;
+
+			o->animation = animation;
+			mask->animation = animation;
+		}
 
 		double fval;
 		if (config_setting_lookup_float(setting, "opacity", &fval)) {
@@ -476,7 +487,8 @@ char *parse_config_libconfig(options_t *opt, const char *config_file, bool *shad
 	}
 	// --sw-opti
 	if (lcfg_lookup_bool(&cfg, "sw-opti", &bval)) {
-		log_warn("The sw-opti %s", deprecation_message);
+		log_error("The sw-opti %s", deprecation_message);
+		goto err;
 	}
 	// --use-ewmh-active-win
 	lcfg_lookup_bool(&cfg, "use-ewmh-active-win", &opt->use_ewmh_active_win);
@@ -511,6 +523,70 @@ char *parse_config_libconfig(options_t *opt, const char *config_file, bool *shad
 	parse_cfg_condlst(&cfg, &opt->shadow_clip_list, "clip-shadow-above");
 	// --fade-exclude
 	parse_cfg_condlst(&cfg, &opt->fade_blacklist, "fade-exclude");
+	// --animations
+	lcfg_lookup_bool(&cfg, "animations", &opt->animations);
+	// --animation-for-open-window
+	if (config_lookup_string(&cfg, "animation-for-open-window", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid open-window animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_open_window = animation;
+	}
+	// --animation-for-transient-window
+	if (config_lookup_string(&cfg, "animation-for-transient-window", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid open-window animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_transient_window = animation;
+	}
+	// --animation-for-unmap-window
+	if (config_lookup_string(&cfg, "animation-for-unmap-window", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid unmap-window animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_unmap_window = animation;
+	}
+	// --animation-for-next-tag
+	if (config_lookup_string(&cfg, "animation-for-next-tag", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid next-tag animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_next_tag = animation;
+	}
+	// --animation-for-prev-tag
+	if (config_lookup_string(&cfg, "animation-for-prev-tag", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid prev-tag animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_prev_tag = animation;
+	}
+	// --animations-exclude
+	parse_cfg_condlst(&cfg, &opt->animation_blacklist, "animation-exclude");
+
+	// --animation-stiffness
+	config_lookup_float(&cfg, "animation-stiffness-in-tag", &opt->animation_stiffness);
+	// --animation-stiffness-tag-change
+	config_lookup_float(&cfg, "animation-stiffness-tag-change", &opt->animation_stiffness_tag_change);
+	// --enable-fading-next-tag
+	lcfg_lookup_bool(&cfg, "enable-fading-next-tag", &opt->enable_fading_next_tag);
+	// --enable-fading-next-tag
+	lcfg_lookup_bool(&cfg, "enable-fading-prev-tag", &opt->enable_fading_prev_tag);
+	// --animation-window-mass
+	config_lookup_float(&cfg, "animation-window-mass", &opt->animation_window_mass);
+	// --animation-dampening
+	config_lookup_float(&cfg, "animation-dampening", &opt->animation_dampening);
+	// --animation-clamping
+	lcfg_lookup_bool(&cfg, "animation-clamping", &opt->animation_clamping);
 	// --focus-exclude
 	parse_cfg_condlst(&cfg, &opt->focus_blacklist, "focus-exclude");
 	// --invert-color-include

src/dbus.c

@@ -906,7 +906,7 @@ cdbus_process_window_property_get(session_t *ps, DBusMessage *msg, cdbus_window_
 	}
 	if (!strcmp("RawFocused", target)) {
 		cdbus_reply(ps, msg, cdbus_append_bool_variant,
-		            (bool[]){win_is_focused_raw(ps, w)});
+		            (bool[]){win_is_focused_raw(w)});
 		return true;
 	}
 
@@ -976,7 +976,7 @@ static bool cdbus_process_win_get(session_t *ps, DBusMessage *msg) {
 	cdbus_m_win_get_do(wmwin, cdbus_reply_bool);
 	cdbus_m_win_get_do(leader, cdbus_reply_wid);
 	if (!strcmp("focused_raw", target)) {
-		cdbus_reply_bool(ps, msg, win_is_focused_raw(ps, w));
+		cdbus_reply_bool(ps, msg, win_is_focused_raw(w));
 		return true;
 	}
 	cdbus_m_win_get_do(fade_force, cdbus_reply_enum);

src/event.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright (c) 2019, Yuxuan Shui <yshuiv7@gmail.com>
 
+#include <stdint.h>
 #include <stdio.h>
 
 #include <X11/Xlibint.h>
@@ -29,7 +30,7 @@
 /// made the query when those events were already in the queue. so the reply you got is
 /// more up-to-date than the events). Also, handling events when other client are making
 /// concurrent requests is not good. Because the server states are changing without you
-/// knowning them. This is super racy, and can cause lots of potential problems.
+/// knowing them. This is super racy, and can cause lots of potential problems.
 ///
 /// All of above mandates we do these things:
 ///    1. Grab server when handling events
@@ -47,8 +48,14 @@
 /// When top half finished, we enter the render stage, where no server state should be
 /// queried. All rendering should be done with our internal knowledge of the server state.
 ///
+/// P.S. There is another reason to avoid sending any request to the server as much as
+/// possible. To make sure requests are sent, flushes are needed. And `xcb_flush`/`XFlush`
+/// functions may read more events from the server into their queues. This is
+/// undesirable, see the comments on `handle_queued_x_events` in picom.c for more details.
 
-// TODO(yshui) the things described above
+// TODO(yshui) the things described above. This is mostly done, maybe some of
+//             the functions here is still making unnecessary queries, we need
+//             to do some auditing to be sure.
 
 /**
  * Get a window's name from window ID.
@@ -324,7 +331,7 @@ static inline void ev_reparent_notify(session_t *ps, xcb_reparent_notify_event_t
 	}
 
 	if (ev->parent == ps->c.screen_info->root) {
-		// X will generate reparent notifiy even if the parent didn't actually
+		// X will generate reparent notify even if the parent didn't actually
 		// change (i.e. reparent again to current parent). So we check if that's
 		// the case
 		auto w = find_win(ps, ev->window);
@@ -350,19 +357,14 @@ static inline void ev_reparent_notify(session_t *ps, xcb_reparent_notify_event_t
 		}
 
 		// Reset event mask in case something wrong happens
-		xcb_change_window_attributes(
-		    ps->c.c, ev->window, XCB_CW_EVENT_MASK,
-		    (const uint32_t[]){determine_evmask(ps, ev->window, WIN_EVMODE_UNKNOWN)});
+		uint32_t evmask = determine_evmask(ps, ev->window, WIN_EVMODE_UNKNOWN);
 
 		if (!wid_has_prop(ps, ev->window, ps->atoms->aWM_STATE)) {
 			log_debug("Window %#010x doesn't have WM_STATE property, it is "
 			          "probably not a client window. But we will listen for "
 			          "property change in case it gains one.",
 			          ev->window);
-			xcb_change_window_attributes(
-			    ps->c.c, ev->window, XCB_CW_EVENT_MASK,
-			    (const uint32_t[]){determine_evmask(ps, ev->window, WIN_EVMODE_UNKNOWN) |
-			                       XCB_EVENT_MASK_PROPERTY_CHANGE});
+			evmask |= XCB_EVENT_MASK_PROPERTY_CHANGE;
 		} else {
 			auto w_real_top = find_managed_window_or_parent(ps, ev->parent);
 			if (w_real_top && w_real_top->state != WSTATE_UNMAPPED &&
@@ -386,6 +388,8 @@ static inline void ev_reparent_notify(session_t *ps, xcb_reparent_notify_event_t
 				}
 			}
 		}
+		XCB_AWAIT_VOID(xcb_change_window_attributes, ps->c.c, ev->window,
+		               XCB_CW_EVENT_MASK, (const uint32_t[]){evmask});
 	}
 }
 
@@ -465,7 +469,7 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 			}
 		}
 
-		// Unconcerned about any other proprties on root window
+		// Unconcerned about any other properties on root window
 		return;
 	}
 
@@ -475,9 +479,10 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 		// Check whether it could be a client window
 		if (!find_toplevel(ps, ev->window)) {
 			// Reset event mask anyway
-			xcb_change_window_attributes(ps->c.c, ev->window, XCB_CW_EVENT_MASK,
-			                             (const uint32_t[]){determine_evmask(
-			                                 ps, ev->window, WIN_EVMODE_UNKNOWN)});
+			const uint32_t evmask =
+			    determine_evmask(ps, ev->window, WIN_EVMODE_UNKNOWN);
+			XCB_AWAIT_VOID(xcb_change_window_attributes, ps->c.c, ev->window,
+			               XCB_CW_EVENT_MASK, (const uint32_t[]){evmask});
 
 			auto w_top = find_managed_window_or_parent(ps, ev->window);
 			// ev->window might have not been managed yet, in that case w_top
@@ -492,14 +497,14 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 	// If _NET_WM_WINDOW_TYPE changes... God knows why this would happen, but
 	// there are always some stupid applications. (#144)
 	if (ev->atom == ps->atoms->a_NET_WM_WINDOW_TYPE) {
-		struct managed_win *w = NULL;
-		if ((w = find_toplevel(ps, ev->window))) {
+		struct managed_win *w = find_toplevel(ps, ev->window);
+		if (w) {
 			win_set_property_stale(w, ev->atom);
 		}
 	}
 
 	if (ev->atom == ps->atoms->a_NET_WM_BYPASS_COMPOSITOR) {
-		// Unnecessay until we remove the queue_redraw in ev_handle
+		// Unnecessary until we remove the queue_redraw in ev_handle
 		queue_redraw(ps);
 	}
 
@@ -560,6 +565,13 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 		}
 	}
 
+	if (!ps->o.no_ewmh_fullscreen && ev->atom == ps->atoms->a_NET_WM_STATE) {
+		auto w = find_toplevel(ps, ev->window);
+		if (w) {
+			win_set_property_stale(w, ev->atom);
+		}
+	}
+
 	// Check for other atoms we are tracking
 	for (latom_t *platom = ps->track_atom_lst; platom; platom = platom->next) {
 		if (platom->atom == ev->atom) {
@@ -586,16 +598,28 @@ static inline void repair_win(session_t *ps, struct managed_win *w) {
 	region_t parts;
 	pixman_region32_init(&parts);
 
+	// If this is the first time this window is damaged, we would redraw the
+	// whole window, so we don't need to fetch the damage region. But we still need
+	// to make sure the X server receives the DamageSubtract request, hence the
+	// `xcb_request_check` here.
+	// Otherwise, we fetch the damage regions. That means we will receive a reply
+	// from the X server, which implies it has received our DamageSubtract request.
 	if (!w->ever_damaged) {
-		win_extents(w, &parts);
-		if (!ps->o.show_all_xerrors) {
-			set_ignore_cookie(&ps->c, xcb_damage_subtract(ps->c.c, w->damage,
-			                                              XCB_NONE, XCB_NONE));
+		auto e = xcb_request_check(
+		    ps->c.c, xcb_damage_subtract(ps->c.c, w->damage, XCB_NONE, XCB_NONE));
+		if (e) {
+			if (ps->o.show_all_xerrors) {
+				x_print_error(e->sequence, e->major_code, e->minor_code,
+				              e->error_code);
+			}
+			free(e);
 		}
+		win_extents(w, &parts);
 	} else {
+		auto cookie =
+		    xcb_damage_subtract(ps->c.c, w->damage, XCB_NONE, ps->damaged_region);
 		if (!ps->o.show_all_xerrors) {
-			set_ignore_cookie(&ps->c, xcb_damage_subtract(ps->c.c, w->damage, XCB_NONE,
-			                                              ps->damaged_region));
+			set_ignore_cookie(&ps->c, cookie);
 		}
 		x_fetch_region(&ps->c, ps->damaged_region, &parts);
 		pixman_region32_translate(&parts, w->g.x + w->g.border_width,
@@ -716,7 +740,8 @@ void ev_handle(session_t *ps, xcb_generic_event_t *ev) {
 	// XXX redraw needs to be more fine grained
 	queue_redraw(ps);
 
-	// the events sent from SendEvent will be ignored
+	// We intentionally ignore events sent via SendEvent. Those events has the 8th bit
+	// of response_type set, meaning they will match none of the cases below.
 	switch (ev->response_type) {
 	case FocusIn: ev_focus_in(ps, (xcb_focus_in_event_t *)ev); break;
 	case FocusOut: ev_focus_out(ps, (xcb_focus_out_event_t *)ev); break;

src/file_watch.c

@@ -158,7 +158,7 @@ bool file_watch_add(void *_fwr, const char *filename, file_watch_cb_t cb, void *
 	fflags |= NOTE_CLOSE_WRITE;
 #else
 	// NOTE_WRITE will receive notification more frequent than necessary, so is less
-	// preferrable
+	// preferable
 	fflags |= NOTE_WRITE;
 #endif
 	struct kevent ev = {

src/kernel.c

@@ -96,7 +96,7 @@ static inline double estimate_first_row_sum(double size, double r) {
 	// `a` is gaussian at (size, 0)
 	double a = exp(-0.5 * size * size / (r * r)) / sqrt(2 * M_PI) / r;
 	// The sum of the whole kernel is normalized to 1, i.e. each element is divided by
-	// factor sqaured. So the sum of the first row is a * factor / factor^2 = a /
+	// factor squared. So the sum of the first row is a * factor / factor^2 = a /
 	// factor
 	return a / factor;
 }

src/list.h

@@ -2,18 +2,7 @@
 #include <stdbool.h>
 #include <stddef.h>
 
-/**
- * container_of - cast a member of a structure out to the containing structure
- * @ptr:	the pointer to the member.
- * @type:	the type of the container struct this is embedded in.
- * @member:	the name of the member within the struct.
- *
- */
-#define container_of(ptr, type, member)                                                  \
-	({                                                                               \
-		const __typeof__(((type *)0)->member) *__mptr = (ptr);                   \
-		(type *)((char *)__mptr - offsetof(type, member));                       \
-	})
+#include "utils.h"
 
 struct list_node {
 	struct list_node *next, *prev;

src/log.c

@@ -9,7 +9,7 @@
 #include <unistd.h>
 
 #ifdef CONFIG_OPENGL
-#include <GL/gl.h>
+#include <epoxy/gl.h>
 #include "backend/gl/gl_common.h"
 #include "backend/gl/glx.h"
 #endif
@@ -338,21 +338,14 @@ struct log_target *stderr_logger_new(void) {
 }
 
 #ifdef CONFIG_OPENGL
-/// An opengl logger that can be used for logging into opengl debugging tools,
-/// such as apitrace
-struct gl_string_marker_logger {
-	struct log_target tgt;
-	PFNGLSTRINGMARKERGREMEDYPROC gl_string_marker;
-};
 
-static void
-gl_string_marker_logger_write(struct log_target *tgt, const char *str, size_t len) {
-	auto g = (struct gl_string_marker_logger *)tgt;
+static void gl_string_marker_logger_write(struct log_target *tgt attr_unused,
+                                          const char *str, size_t len) {
 	// strip newlines at the end of the string
 	while (len > 0 && str[len - 1] == '\n') {
 		len--;
 	}
-	g->gl_string_marker((GLsizei)len, str);
+	glStringMarkerGREMEDY((GLsizei)len, str);
 }
 
 static const struct log_ops gl_string_marker_logger_ops = {
@@ -361,20 +354,16 @@ static const struct log_ops gl_string_marker_logger_ops = {
     .destroy = logger_trivial_destroy,
 };
 
+/// Create an opengl logger that can be used for logging into opengl debugging tools,
+/// such as apitrace
 struct log_target *gl_string_marker_logger_new(void) {
-	if (!gl_has_extension("GL_GREMEDY_string_marker")) {
+	if (!epoxy_has_gl_extension("GL_GREMEDY_string_marker")) {
 		return NULL;
 	}
 
-	void *fnptr = glXGetProcAddress((GLubyte *)"glStringMarkerGREMEDY");
-	if (!fnptr) {
-		return NULL;
-	}
-
-	auto ret = cmalloc(struct gl_string_marker_logger);
-	ret->tgt.ops = &gl_string_marker_logger_ops;
-	ret->gl_string_marker = fnptr;
-	return &ret->tgt;
+	auto ret = cmalloc(struct log_target);
+	ret->ops = &gl_string_marker_logger_ops;
+	return ret;
 }
 
 #else

src/meson.build

@@ -9,7 +9,8 @@ base_deps = [
 
 srcs = [ files('picom.c', 'win.c', 'c2.c', 'x.c', 'config.c', 'vsync.c', 'utils.c',
                'diagnostic.c', 'string_utils.c', 'render.c', 'kernel.c', 'log.c',
-               'options.c', 'event.c', 'cache.c', 'atom.c', 'file_watch.c', 'statistics.c') ]
+               'options.c', 'event.c', 'cache.c', 'atom.c', 'file_watch.c', 'statistics.c',
+               'vblank.c') ]
 picom_inc = include_directories('.')
 
 cflags = []
@@ -22,7 +23,7 @@ required_xcb_packages = [
 # Some XCB packages are here because their versioning differs (see check below).
 required_packages = [
 	'pixman-1', 'x11', 'x11-xcb', 'xcb-image', 'xcb-renderutil', 'xcb-util',
-	'xext'
+	'xext', 'threads',
 ]
 
 foreach i : required_packages
@@ -57,8 +58,8 @@ if get_option('vsync_drm')
 endif
 
 if get_option('opengl')
-	cflags += ['-DCONFIG_OPENGL', '-DGL_GLEXT_PROTOTYPES']
-	deps += [dependency('gl', required: true), dependency('egl', required: true)]
+	cflags += ['-DCONFIG_OPENGL']
+	deps += [dependency('epoxy', required: true)]
 	srcs += [ 'opengl.c' ]
 endif
 

src/opengl.c

@@ -181,7 +181,7 @@ bool glx_init(session_t *ps, bool need_render) {
 	// must precede FBConfig fetching
 	if (need_render) {
 		psglx->has_texture_non_power_of_two =
-		    gl_has_extension("GL_ARB_texture_non_power_of_two");
+		    epoxy_has_gl_extension("GL_ARB_texture_non_power_of_two");
 	}
 
 	// Render preparations
@@ -279,7 +279,7 @@ void glx_destroy(session_t *ps) {
 
 	free(ps->psglx);
 	ps->psglx = NULL;
-	ps->argb_fbconfig = NULL;
+	ps->argb_fbconfig = (struct glx_fbconfig_info){0};
 }
 
 /**
@@ -1129,7 +1129,7 @@ glx_blur_dst_end:
 // TODO(bhagwan) this is a mess and needs a more consistent way of getting the border
 // pixel I tried looking for a notify event for XCB_CW_BORDER_PIXEL (in
 // xcb_create_window()) or a way to get the pixels from xcb_render_picture_t but the
-// documentation for the xcb_xrender extension is literaly non existent...
+// documentation for the xcb_xrender extension is literally non existent...
 //
 // NOTE(yshui) There is no consistent way to get the "border" color of a X window. From
 // the WM's perspective there are multiple ways to implement window borders. Using

src/opengl.h

@@ -18,9 +18,9 @@
 #include "render.h"
 #include "win.h"
 
-#include <GL/gl.h>
-#include <GL/glx.h>
 #include <ctype.h>
+#include <epoxy/gl.h>
+#include <epoxy/glx.h>
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
@@ -75,7 +75,7 @@ typedef struct glx_session {
 	glx_round_pass_t *round_passes;
 } glx_session_t;
 
-/// @brief Wrapper of a binded GLX texture.
+/// @brief Wrapper of a bound GLX texture.
 typedef struct _glx_texture {
 	GLuint texture;
 	GLXPixmap glpixmap;
@@ -121,9 +121,9 @@ bool glx_bind_texture(session_t *ps, glx_texture_t **pptex, int x, int y, int wi
 void glx_paint_pre(session_t *ps, region_t *preg) attr_nonnull(1, 2);
 
 /**
- * Check if a texture is binded, or is binded to the given pixmap.
+ * Check if a texture is bound, or is bound to the given pixmap.
  */
-static inline bool glx_tex_binded(const glx_texture_t *ptex, xcb_pixmap_t pixmap) {
+static inline bool glx_tex_bound(const glx_texture_t *ptex, xcb_pixmap_t pixmap) {
 	return ptex && ptex->glpixmap && ptex->texture && (!pixmap || pixmap == ptex->pixmap);
 }
 
@@ -228,10 +228,7 @@ static inline void free_texture(session_t *ps, glx_texture_t **pptex) {
  */
 static inline void free_paint_glx(session_t *ps, paint_t *ppaint) {
 	free_texture(ps, &ppaint->ptex);
-#ifdef CONFIG_OPENGL
-	free(ppaint->fbcfg);
-#endif
-	ppaint->fbcfg = NULL;
+	ppaint->fbcfg = (struct glx_fbconfig_info){0};
 }
 
 /**

src/options.c

@@ -184,6 +184,15 @@ static const struct picom_option picom_options[] = {
                                                                              "you want to attach a debugger to picom"},
     {"no-ewmh-fullscreen"          , no_argument      , 803, NULL          , "Do not use EWMH to detect fullscreen windows. Reverts to checking if a "
                                                                              "window is fullscreen based only on its size and coordinates."},
+    {"animations"                  ,no_argument       , 804, NULL          , "Enable/disable animations."},
+    {"animation-stiffness-in-tag"  , required_argument, 805, NULL          , "Animation speed in current tag (float)."},
+    {"animation-stiffness-tag-change", required_argument, 806, NULL        , "Animation speed when tag changes (change to a new desktop)."},
+    {"animation-dampening"         , required_argument, 807, NULL          , "Animation dampening ratio (spring dampening as an example)."},
+    {"animation-window-mass"       , required_argument, 808, NULL          , "Animation window mass (lower mass makes animations bumpy)."},
+    {"animation-clamping"          , no_argument      , 809, NULL          , "Enable/disable animation clamping. Disabling increases performance"},
+    {"animation-for-open-window"   , required_argument, 810, NULL          , "Set animation for opening window (Check sample.conf for options)."},
+    {"animation-for-transient-window", required_argument, 811, NULL        , "Set animation for transient (child) windows."},
+
 };
 // clang-format on
 
@@ -306,7 +315,7 @@ static void usage(const char *argv0, int ret) {
 	}
 }
 
-static const char *shortopts = "D:I:O:r:o:m:l:t:i:e:hscnfFCazGb";
+static const char *shortopts = "D:I:O:r:o:m:l:t:i:e:hscnfCazGb";
 
 /// Get config options that are needed to parse the rest of the options
 /// Return true if we should quit
@@ -316,9 +325,9 @@ bool get_early_config(int argc, char *const *argv, char **config_file, bool *all
 
 	int o = 0, longopt_idx = -1;
 
-	// Pre-parse the commandline arguments to check for --config and invalid
+	// Pre-parse the command line arguments to check for --config and invalid
 	// switches
-	// Must reset optind to 0 here in case we reread the commandline
+	// Must reset optind to 0 here in case we reread the command line
 	// arguments
 	optind = 1;
 	*config_file = NULL;
@@ -370,7 +379,7 @@ bool get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 	// instead of commas in atof().
 	setlocale(LC_NUMERIC, "C");
 
-	// Parse commandline arguments. Range checking will be done later.
+	// Parse command line arguments. Range checking will be done later.
 
 	bool failed = false;
 	const char *deprecation_message attr_unused =
@@ -426,7 +435,6 @@ bool get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 			opt->wintype_option[WINTYPE_DROPDOWN_MENU].opacity = tmp;
 			break;
 		case 'f':
-		case 'F':
 			fading_enable = true;
 			break;
 		P_CASEINT('r', shadow_radius);
@@ -511,8 +519,9 @@ bool get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 			         "--crop-shadow-to-monitor instead.");
 			break;
 		case 274:
-			log_warn("--sw-opti has been deprecated, please remove it from the "
+			log_error("--sw-opti has been deprecated, please remove it from the "
 			         "command line options");
+			failed = true;
 			break;
 		case 275:
 			// --vsync-aggressive
@@ -523,9 +532,10 @@ bool get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 		P_CASEBOOL(276, use_ewmh_active_win);
 		case 277:
 			// --respect-prop-shadow
-			log_warn("--respect-prop-shadow option has been deprecated, its "
+			log_error("--respect-prop-shadow option has been deprecated, its "
 			         "functionality will always be enabled. Please remove it "
 			         "from the command line options");
+			failed = true;
 			break;
 		P_CASEBOOL(278, unredir_if_possible);
 		case 279:
@@ -721,7 +731,7 @@ bool get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 			opt->blur_strength = atoi(optarg);
 			break;
 		case 333:
-			// --cornor-radius
+			// --corner-radius
 			opt->corner_radius = atoi(optarg);
 			break;
 		case 334:
@@ -750,6 +760,52 @@ bool get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 			break;
 		P_CASEBOOL(802, debug_mode);
 		P_CASEBOOL(803, no_ewmh_fullscreen);
+		P_CASEBOOL(804, animations);
+		case 805:
+			// --animation-stiffness
+			opt->animation_stiffness = atof(optarg);
+			break;
+		case 806:
+			// --animation-stiffness-for-tags
+			opt->animation_stiffness_tag_change = atof(optarg);
+			break;
+		case 807:
+			// --animation-dampening
+			opt->animation_dampening = atof(optarg);
+			break;
+		case 808:
+			// --animation-window-masss
+			opt->animation_window_mass = atof(optarg);
+			break;
+		case 809:
+			// --animation-clamping
+			opt->animation_clamping = true;
+			break;
+		case 810: {
+			// --animation-for-open-window
+			enum open_window_animation animation = parse_open_window_animation(optarg);
+			if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+				log_warn("Invalid open-window animation %s, ignoring.", optarg);
+			} else {
+				opt->animation_for_open_window = animation;
+			}
+			break;
+		}
+		case 811: {
+			// --animation-for-transient-window
+			enum open_window_animation animation = parse_open_window_animation(optarg);
+			if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+				log_warn("Invalid transient-window animation %s, ignoring.", optarg);
+			} else {
+				opt->animation_for_transient_window = animation;
+			}
+			break;
+		}
+		case 812: {
+			// --animation-exclude
+			condlst_add(&opt->animation_blacklist, optarg);
+			break;
+		}
 		default: usage(argv[0], 1); break;
 #undef P_CASEBOOL
 		}

src/render.c

@@ -6,6 +6,7 @@
 #include <xcb/composite.h>
 #include <xcb/render.h>
 #include <xcb/sync.h>
+#include <xcb/xcb_aux.h>
 #include <xcb/xcb_image.h>
 #include <xcb/xcb_renderutil.h>
 
@@ -55,19 +56,20 @@ static inline bool paint_bind_tex(session_t *ps, paint_t *ppaint, int wid, int h
 	struct glx_fbconfig_info *fbcfg;
 	if (!visual) {
 		assert(depth == 32);
-		if (!ps->argb_fbconfig) {
-			ps->argb_fbconfig = glx_find_fbconfig(
-			    &ps->c, (struct xvisual_info){.red_size = 8,
-			                                  .green_size = 8,
-			                                  .blue_size = 8,
-			                                  .alpha_size = 8,
-			                                  .visual_depth = 32});
+		if (!ps->argb_fbconfig.cfg) {
+			glx_find_fbconfig(&ps->c,
+			                  (struct xvisual_info){.red_size = 8,
+			                                        .green_size = 8,
+			                                        .blue_size = 8,
+			                                        .alpha_size = 8,
+			                                        .visual_depth = 32},
+			                  &ps->argb_fbconfig);
 		}
-		if (!ps->argb_fbconfig) {
+		if (!ps->argb_fbconfig.cfg) {
 			log_error("Failed to find appropriate FBConfig for 32 bit depth");
 			return false;
 		}
-		fbcfg = ps->argb_fbconfig;
+		fbcfg = &ps->argb_fbconfig;
 	} else {
 		auto m = x_get_visual_info(&ps->c, visual);
 		if (m.visual_depth < 0) {
@@ -79,17 +81,17 @@ static inline bool paint_bind_tex(session_t *ps, paint_t *ppaint, int wid, int h
 			return false;
 		}
 
-		if (!ppaint->fbcfg) {
-			ppaint->fbcfg = glx_find_fbconfig(&ps->c, m);
+		if (!ppaint->fbcfg.cfg) {
+			glx_find_fbconfig(&ps->c, m, &ppaint->fbcfg);
 		}
-		if (!ppaint->fbcfg) {
+		if (!ppaint->fbcfg.cfg) {
 			log_error("Failed to find appropriate FBConfig for X pixmap");
 			return false;
 		}
-		fbcfg = ppaint->fbcfg;
+		fbcfg = &ppaint->fbcfg;
 	}
 
-	if (force || !glx_tex_binded(ppaint->ptex, ppaint->pixmap)) {
+	if (force || !glx_tex_bound(ppaint->ptex, ppaint->pixmap)) {
 		return glx_bind_pixmap(ps, &ppaint->ptex, ppaint->pixmap, wid, hei,
 		                       repeat, fbcfg);
 	}
@@ -378,7 +380,7 @@ static inline bool paint_isvalid(session_t *ps, const paint_t *ppaint) {
 	}
 
 #ifdef CONFIG_OPENGL
-	if (BKEND_GLX == ps->o.backend && !glx_tex_binded(ppaint->ptex, XCB_NONE)) {
+	if (BKEND_GLX == ps->o.backend && !glx_tex_bound(ppaint->ptex, XCB_NONE)) {
 		return false;
 	}
 #endif
@@ -604,20 +606,27 @@ static bool get_root_tile(session_t *ps) {
 	bool fill = false;
 	xcb_pixmap_t pixmap = x_get_root_back_pixmap(&ps->c, ps->atoms);
 
-	// Make sure the pixmap we got is valid
-	if (pixmap && !x_validate_pixmap(&ps->c, pixmap)) {
-		pixmap = XCB_NONE;
+	xcb_get_geometry_reply_t *r;
+	if (pixmap) {
+		r = xcb_get_geometry_reply(ps->c.c, xcb_get_geometry(ps->c.c, pixmap), NULL);
 	}
 
 	// Create a pixmap if there isn't any
-	if (!pixmap) {
+	xcb_visualid_t visual;
+	if (!pixmap || !r) {
 		pixmap =
 		    x_create_pixmap(&ps->c, (uint8_t)ps->c.screen_info->root_depth, 1, 1);
 		if (pixmap == XCB_NONE) {
 			log_error("Failed to create pixmaps for root tile.");
 			return false;
 		}
+		visual = ps->c.screen_info->root_visual;
 		fill = true;
+	} else {
+		visual = r->depth == ps->c.screen_info->root_depth
+		             ? ps->c.screen_info->root_visual
+		             : x_get_visual_for_depth(ps->c.screen_info, r->depth);
+		free(r);
 	}
 
 	// Create Picture
@@ -625,7 +634,7 @@ static bool get_root_tile(session_t *ps) {
 	    .repeat = true,
 	};
 	ps->root_tile_paint.pict = x_create_picture_with_visual_and_pixmap(
-	    &ps->c, ps->c.screen_info->root_visual, pixmap, XCB_RENDER_CP_REPEAT, &pa);
+	    &ps->c, visual, pixmap, XCB_RENDER_CP_REPEAT, &pa);
 
 	// Fill pixmap if needed
 	if (fill) {
@@ -646,8 +655,7 @@ static bool get_root_tile(session_t *ps) {
 	ps->root_tile_paint.pixmap = pixmap;
 #ifdef CONFIG_OPENGL
 	if (BKEND_GLX == ps->o.backend) {
-		return paint_bind_tex(ps, &ps->root_tile_paint, 0, 0, true, 0,
-		                      ps->c.screen_info->root_visual, false);
+		return paint_bind_tex(ps, &ps->root_tile_paint, 0, 0, true, 0, visual, false);
 	}
 #endif
 
@@ -1223,7 +1231,7 @@ void paint_all(session_t *ps, struct managed_win *t) {
 	if (ps->o.vsync) {
 		// Make sure all previous requests are processed to achieve best
 		// effect
-		x_sync(&ps->c);
+		xcb_aux_sync(ps->c.c);
 #ifdef CONFIG_OPENGL
 		if (glx_has_context(ps)) {
 			if (ps->o.vsync_use_glfinish) {
@@ -1282,7 +1290,7 @@ void paint_all(session_t *ps, struct managed_win *t) {
 		break;
 #ifdef CONFIG_OPENGL
 	case BKEND_XR_GLX_HYBRID:
-		x_sync(&ps->c);
+		xcb_aux_sync(ps->c.c);
 		if (ps->o.vsync_use_glfinish) {
 			glFinish();
 		} else {
@@ -1307,7 +1315,7 @@ void paint_all(session_t *ps, struct managed_win *t) {
 	default: assert(0);
 	}
 
-	x_sync(&ps->c);
+	xcb_aux_sync(ps->c.c);
 
 #ifdef CONFIG_OPENGL
 	if (glx_has_context(ps)) {
@@ -1522,7 +1530,7 @@ void deinit_render(session_t *ps) {
 	free_root_tile(ps);
 
 #ifdef CONFIG_OPENGL
-	free(ps->root_tile_paint.fbcfg);
+	ps->root_tile_paint.fbcfg = (struct glx_fbconfig_info){0};
 	if (bkend_use_glx(ps)) {
 		glx_destroy(ps);
 	}

src/render.h

@@ -21,7 +21,7 @@ typedef struct paint {
 	xcb_render_picture_t pict;
 	glx_texture_t *ptex;
 #ifdef CONFIG_OPENGL
-	struct glx_fbconfig_info *fbcfg;
+	struct glx_fbconfig_info fbcfg;
 #endif
 } paint_t;
 

src/statistics.c

@@ -51,30 +51,15 @@ void render_statistics_add_render_time_sample(struct render_statistics *rs, int
 }
 
 /// How much time budget we should give to the backend for rendering, in microseconds.
-///
-/// A `divisor` is also returned, indicating the target framerate. The divisor is
-/// the number of vblanks we should wait between each frame. A divisor of 1 means
-/// full framerate, 2 means half framerate, etc.
-unsigned int
-render_statistics_get_budget(struct render_statistics *rs, unsigned int *divisor) {
+unsigned int render_statistics_get_budget(struct render_statistics *rs) {
 	if (rs->render_times.nelem < rs->render_times.window_size) {
 		// No valid render time estimates yet. Assume maximum budget.
-		*divisor = 1;
 		return UINT_MAX;
 	}
 
 	// N-th percentile of render times, see render_statistics_init for N.
 	auto render_time_percentile =
 	    rolling_quantile_estimate(&rs->render_time_quantile, &rs->render_times);
-	auto vblank_time_us = render_statistics_get_vblank_time(rs);
-	if (vblank_time_us == 0) {
-		// We don't have a good estimate of the vblank time yet, so we
-		// assume we can finish in one vblank.
-		*divisor = 1;
-	} else {
-		*divisor =
-		    (unsigned int)(render_time_percentile / rs->vblank_time_us.mean + 1);
-	}
 	return (unsigned int)render_time_percentile;
 }
 

src/statistics.h

@@ -23,11 +23,8 @@ void render_statistics_add_vblank_time_sample(struct render_statistics *rs, int
 void render_statistics_add_render_time_sample(struct render_statistics *rs, int time_us);
 
 /// How much time budget we should give to the backend for rendering, in microseconds.
-///
-/// A `divisor` is also returned, indicating the target framerate. The divisor is
-/// the number of vblanks we should wait between each frame. A divisor of 1 means
-/// full framerate, 2 means half framerate, etc.
-unsigned int
-render_statistics_get_budget(struct render_statistics *rs, unsigned int *divisor);
+unsigned int render_statistics_get_budget(struct render_statistics *rs);
 
+/// Return the measured vblank interval in microseconds. Returns 0 if not enough
+/// samples have been collected yet.
 unsigned int render_statistics_get_vblank_time(struct render_statistics *rs);

src/utils.c

@@ -141,10 +141,10 @@ void rolling_max_pop_front(struct rolling_max *rm, int front) {
 }
 
 void rolling_max_push_back(struct rolling_max *rm, int val) {
-	// Update the prority queue.
+	// Update the priority queue.
 	// Remove all elements smaller than the new element from the queue. Because
 	// the new element will become the maximum element before them, and since they
-	// come b1efore the new element, they will have been popped before the new
+	// come before the new element, they will have been popped before the new
 	// element, so they will never become the maximum element.
 	while (rm->np) {
 		int p_tail = IDX(rm->p_head + rm->np - 1);

src/utils.h

@@ -21,6 +21,7 @@
 #include "types.h"
 
 #define ARR_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
+#define CLEAR_MASK(x) x = 0;
 
 #ifdef __FAST_MATH__
 #warning Use of -ffast-math can cause rendering error or artifacts, \
@@ -58,11 +59,11 @@ safe_isnan(double a) {
 /// being always true or false.
 #define ASSERT_IN_RANGE(var, lower, upper)                                               \
 	do {                                                                             \
-		auto __tmp attr_unused = (var);                                          \
+		auto __assert_in_range_tmp attr_unused = (var);                          \
 		_Pragma("GCC diagnostic push");                                          \
 		_Pragma("GCC diagnostic ignored \"-Wtype-limits\"");                     \
-		assert(__tmp >= lower);                                                  \
-		assert(__tmp <= upper);                                                  \
+		assert(__assert_in_range_tmp >= lower);                                  \
+		assert(__assert_in_range_tmp <= upper);                                  \
 		_Pragma("GCC diagnostic pop");                                           \
 	} while (0)
 
@@ -112,11 +113,26 @@ safe_isnan(double a) {
 #define to_u32_checked(val)                                                              \
 	({                                                                               \
 		auto __to_tmp = (val);                                                   \
-		int64_t max attr_unused = UINT32_MAX; /* silence clang tautological      \
-		                                         comparison warning*/            \
-		ASSERT_IN_RANGE(__to_tmp, 0, max);                                       \
+		int64_t __to_u32_max attr_unused = UINT32_MAX; /* silence clang          \
+		                                                  tautological           \
+		                                                  comparison warning */  \
+		ASSERT_IN_RANGE(__to_tmp, 0, __to_u32_max);                              \
 		(uint32_t) __to_tmp;                                                     \
 	})
+
+/**
+ * container_of - cast a member of a structure out to the containing structure
+ * @ptr:	the pointer to the member.
+ * @type:	the type of the container struct this is embedded in.
+ * @member:	the name of the member within the struct.
+ *
+ */
+#define container_of(ptr, type, member)                                                  \
+	({                                                                               \
+		const __typeof__(((type *)0)->member) *__mptr = (ptr);                   \
+		(type *)((char *)__mptr - offsetof(type, member));                       \
+	})
+
 /**
  * Normalize an int value to a specific range.
  *
@@ -125,14 +141,35 @@ safe_isnan(double a) {
  * @param max maximum value
  * @return normalized value
  */
-static inline int attr_const normalize_i_range(int i, int min, int max) {
-	if (i > max)
+static inline int attr_const attr_unused normalize_i_range(int i, int min, int max) {
+	if (i > max) {
 		return max;
-	if (i < min)
+	}
+	if (i < min) {
 		return min;
+	}
 	return i;
 }
 
+/**
+ * Linearly interpolate from a range into another.
+ *
+ * @param  a,b   first range
+ * @param  c,d   second range
+ * @param  value value to interpolate, should be in range [a,b]
+ * @return interpolated value in range [c,d]
+ */
+static inline int attr_const lerp_range(int a, int b, int c, int d, int value) {
+	ASSERT_IN_RANGE(value, a, b);
+	return (d-c)*(value-a)/(b-a) + c;
+}
+
+/// Generic integer abs()
+#define iabs(val)                                                                        \
+	({                                                                               \
+		__auto_type __tmp = (val);                                               \
+		__tmp > 0 ? __tmp : -__tmp;                                              \
+	})
 #define min2(a, b) ((a) > (b) ? (b) : (a))
 #define max2(a, b) ((a) > (b) ? (a) : (b))
 #define min3(a, b, c) min2(a, min2(b, c))
@@ -149,10 +186,12 @@ static inline int attr_const normalize_i_range(int i, int min, int max) {
  * @return normalized value
  */
 static inline double attr_const normalize_d_range(double d, double min, double max) {
-	if (d > max)
+	if (d > max) {
 		return max;
-	if (d < min)
+	}
+	if (d < min) {
 		return min;
+	}
 	return d;
 }
 
@@ -162,7 +201,7 @@ static inline double attr_const normalize_d_range(double d, double min, double m
  * @param d double value to normalize
  * @return normalized value
  */
-static inline double attr_const normalize_d(double d) {
+static inline double attr_const attr_unused normalize_d(double d) {
 	return normalize_d_range(d, 0.0, 1.0);
 }
 
@@ -212,7 +251,7 @@ allocchk_(const char *func_name, const char *file, unsigned int line, void *ptr)
 		((type *)allocchk(calloc((size_t)tmp, sizeof(type))));                   \
 	})
 
-/// @brief Wrapper of ealloc().
+/// @brief Wrapper of realloc().
 #define crealloc(ptr, nmemb)                                                               \
 	({                                                                                 \
 		auto tmp = (nmemb);                                                        \

src/vblank.c

@@ -0,0 +1,569 @@
+#include <assert.h>
+
+#include <ev.h>
+#include <inttypes.h>
+#include <stdatomic.h>
+#include <string.h>
+#include <time.h>
+#include <xcb/xcb.h>
+#include <xcb/xproto.h>
+#include "config.h"
+
+#ifdef CONFIG_OPENGL
+// Enable sgi_video_sync_vblank_scheduler
+#include <X11/X.h>
+#include <X11/Xlib-xcb.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <epoxy/glx.h>
+#include <pthread.h>
+
+#endif
+
+#include "compiler.h"
+#include "list.h"        // for container_of
+#include "log.h"
+#include "vblank.h"
+#include "x.h"
+
+struct vblank_closure {
+	vblank_callback_t fn;
+	void *user_data;
+};
+
+#define VBLANK_WIND_DOWN 4
+
+struct vblank_scheduler {
+	struct x_connection *c;
+	size_t callback_capacity, callback_count;
+	struct vblank_closure *callbacks;
+	struct ev_loop *loop;
+	/// Request extra vblank events even when no callbacks are scheduled.
+	/// This is because when callbacks are scheduled too close to a vblank,
+	/// we might send PresentNotifyMsc request too late and miss the vblank event.
+	/// So we request extra vblank events right after the last vblank event
+	/// to make sure this doesn't happen.
+	unsigned int wind_down;
+	xcb_window_t target_window;
+	enum vblank_scheduler_type type;
+	bool vblank_event_requested;
+};
+
+struct present_vblank_scheduler {
+	struct vblank_scheduler base;
+
+	uint64_t last_msc;
+	/// The timestamp for the end of last vblank.
+	uint64_t last_ust;
+	ev_timer callback_timer;
+	xcb_present_event_t event_id;
+	xcb_special_event_t *event;
+};
+
+struct vblank_scheduler_ops {
+	size_t size;
+	bool (*init)(struct vblank_scheduler *self);
+	void (*deinit)(struct vblank_scheduler *self);
+	bool (*schedule)(struct vblank_scheduler *self);
+	bool (*handle_x_events)(struct vblank_scheduler *self);
+};
+
+static void
+vblank_scheduler_invoke_callbacks(struct vblank_scheduler *self, struct vblank_event *event);
+
+#ifdef CONFIG_OPENGL
+struct sgi_video_sync_vblank_scheduler {
+	struct vblank_scheduler base;
+
+	// Since glXWaitVideoSyncSGI blocks, we need to run it in a separate thread.
+	// ... and all the thread shenanigans that come with it.
+	_Atomic unsigned int current_msc;
+	_Atomic uint64_t current_ust;
+	ev_async notify;
+	pthread_t sync_thread;
+	bool running, error;
+	unsigned int last_msc;
+
+	/// Protects `running`, and `base.vblank_event_requested`
+	pthread_mutex_t vblank_requested_mtx;
+	pthread_cond_t vblank_requested_cnd;
+};
+
+struct sgi_video_sync_thread_args {
+	struct sgi_video_sync_vblank_scheduler *self;
+	int start_status;
+	pthread_mutex_t start_mtx;
+	pthread_cond_t start_cnd;
+};
+
+static bool check_sgi_video_sync_extension(Display *dpy, int screen) {
+	const char *glx_ext = glXQueryExtensionsString(dpy, screen);
+	const char *needle = "GLX_SGI_video_sync";
+	char *found = strstr(glx_ext, needle);
+	if (!found) {
+		return false;
+	}
+	if (found != glx_ext && found[-1] != ' ') {
+		return false;
+	}
+	if (found[strlen(needle)] != ' ' && found[strlen(needle)] != '\0') {
+		return false;
+	}
+
+	return true;
+}
+
+static void *sgi_video_sync_thread(void *data) {
+	auto args = (struct sgi_video_sync_thread_args *)data;
+	auto self = args->self;
+	Display *dpy = XOpenDisplay(NULL);
+	int error_code = 0;
+	if (!dpy) {
+		error_code = 1;
+		goto start_failed;
+	}
+	Window root = DefaultRootWindow(dpy), dummy = None;
+	int screen = DefaultScreen(dpy);
+	int ncfg = 0;
+	GLXFBConfig *cfg_ = glXChooseFBConfig(
+	    dpy, screen,
+	    (int[]){GLX_RENDER_TYPE, GLX_RGBA_BIT, GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT, 0},
+	    &ncfg);
+	GLXContext ctx = NULL;
+	GLXDrawable drawable = None;
+
+	if (!cfg_) {
+		error_code = 2;
+		goto start_failed;
+	}
+	GLXFBConfig cfg = cfg_[0];
+	XFree(cfg_);
+
+	XVisualInfo *vi = glXGetVisualFromFBConfig(dpy, cfg);
+	if (!vi) {
+		error_code = 3;
+		goto start_failed;
+	}
+
+	Visual *visual = vi->visual;
+	const int depth = vi->depth;
+	XFree(vi);
+
+	Colormap colormap = XCreateColormap(dpy, root, visual, AllocNone);
+	XSetWindowAttributes attributes;
+	attributes.colormap = colormap;
+
+	dummy = XCreateWindow(dpy, root, 0, 0, 1, 1, 0, depth, InputOutput, visual,
+	                      CWColormap, &attributes);
+	XFreeColormap(dpy, colormap);
+	if (dummy == None) {
+		error_code = 4;
+		goto start_failed;
+	}
+
+	drawable = glXCreateWindow(dpy, cfg, dummy, NULL);
+	if (drawable == None) {
+		error_code = 5;
+		goto start_failed;
+	}
+
+	ctx = glXCreateNewContext(dpy, cfg, GLX_RGBA_TYPE, 0, true);
+	if (ctx == NULL) {
+		error_code = 6;
+		goto start_failed;
+	}
+
+	if (!glXMakeContextCurrent(dpy, drawable, drawable, ctx)) {
+		error_code = 7;
+		goto start_failed;
+	}
+
+	if (!check_sgi_video_sync_extension(dpy, screen)) {
+		error_code = 8;
+		goto start_failed;
+	}
+
+	pthread_mutex_lock(&args->start_mtx);
+	args->start_status = 0;
+	pthread_cond_signal(&args->start_cnd);
+	pthread_mutex_unlock(&args->start_mtx);
+
+	pthread_mutex_lock(&self->vblank_requested_mtx);
+	while (self->running) {
+		if (!self->base.vblank_event_requested) {
+			pthread_cond_wait(&self->vblank_requested_cnd,
+			                  &self->vblank_requested_mtx);
+			continue;
+		}
+		pthread_mutex_unlock(&self->vblank_requested_mtx);
+
+		unsigned int last_msc;
+		glXWaitVideoSyncSGI(1, 0, &last_msc);
+
+		struct timespec now;
+		clock_gettime(CLOCK_MONOTONIC, &now);
+		atomic_store(&self->current_msc, last_msc);
+		atomic_store(&self->current_ust,
+		             (uint64_t)(now.tv_sec * 1000000 + now.tv_nsec / 1000));
+		ev_async_send(self->base.loop, &self->notify);
+		pthread_mutex_lock(&self->vblank_requested_mtx);
+	}
+	pthread_mutex_unlock(&self->vblank_requested_mtx);
+	goto cleanup;
+
+start_failed:
+	pthread_mutex_lock(&args->start_mtx);
+	args->start_status = error_code;
+	pthread_cond_signal(&args->start_cnd);
+	pthread_mutex_unlock(&args->start_mtx);
+
+cleanup:
+	if (dpy) {
+		glXMakeCurrent(dpy, None, NULL);
+		if (ctx) {
+			glXDestroyContext(dpy, ctx);
+		}
+		if (drawable) {
+			glXDestroyWindow(dpy, drawable);
+		}
+		if (dummy) {
+			XDestroyWindow(dpy, dummy);
+		}
+		XCloseDisplay(dpy);
+	}
+	return NULL;
+}
+
+static bool sgi_video_sync_scheduler_schedule(struct vblank_scheduler *base) {
+	auto self = (struct sgi_video_sync_vblank_scheduler *)base;
+	if (self->error) {
+		return false;
+	}
+	log_verbose("Requesting vblank event for msc %d", self->current_msc + 1);
+	pthread_mutex_lock(&self->vblank_requested_mtx);
+	assert(!base->vblank_event_requested);
+	base->vblank_event_requested = true;
+	pthread_cond_signal(&self->vblank_requested_cnd);
+	pthread_mutex_unlock(&self->vblank_requested_mtx);
+	return true;
+}
+
+static void
+sgi_video_sync_scheduler_callback(EV_P attr_unused, ev_async *w, int attr_unused revents);
+
+static bool sgi_video_sync_scheduler_init(struct vblank_scheduler *base) {
+	auto self = (struct sgi_video_sync_vblank_scheduler *)base;
+	auto args = (struct sgi_video_sync_thread_args){
+	    .self = self,
+	    .start_status = -1,
+	};
+	bool succeeded = true;
+	pthread_mutex_init(&args.start_mtx, NULL);
+	pthread_cond_init(&args.start_cnd, NULL);
+
+	base->type = VBLANK_SCHEDULER_SGI_VIDEO_SYNC;
+	ev_async_init(&self->notify, sgi_video_sync_scheduler_callback);
+	ev_async_start(base->loop, &self->notify);
+	pthread_mutex_init(&self->vblank_requested_mtx, NULL);
+	pthread_cond_init(&self->vblank_requested_cnd, NULL);
+
+	self->running = true;
+	pthread_create(&self->sync_thread, NULL, sgi_video_sync_thread, &args);
+
+	pthread_mutex_lock(&args.start_mtx);
+	while (args.start_status == -1) {
+		pthread_cond_wait(&args.start_cnd, &args.start_mtx);
+	}
+	if (args.start_status != 0) {
+		log_fatal("Failed to start sgi_video_sync_thread, error code: %d",
+		          args.start_status);
+		succeeded = false;
+	} else {
+		log_info("Started sgi_video_sync_thread");
+	}
+	self->error = !succeeded;
+	self->last_msc = 0;
+	pthread_mutex_destroy(&args.start_mtx);
+	pthread_cond_destroy(&args.start_cnd);
+	return succeeded;
+}
+
+static void sgi_video_sync_scheduler_deinit(struct vblank_scheduler *base) {
+	auto self = (struct sgi_video_sync_vblank_scheduler *)base;
+	ev_async_stop(base->loop, &self->notify);
+	pthread_mutex_lock(&self->vblank_requested_mtx);
+	self->running = false;
+	pthread_cond_signal(&self->vblank_requested_cnd);
+	pthread_mutex_unlock(&self->vblank_requested_mtx);
+
+	pthread_join(self->sync_thread, NULL);
+
+	pthread_mutex_destroy(&self->vblank_requested_mtx);
+	pthread_cond_destroy(&self->vblank_requested_cnd);
+}
+
+static void
+sgi_video_sync_scheduler_callback(EV_P attr_unused, ev_async *w, int attr_unused revents) {
+	auto sched = container_of(w, struct sgi_video_sync_vblank_scheduler, notify);
+	auto msc = atomic_load(&sched->current_msc);
+	if (sched->last_msc == msc) {
+		// NVIDIA spams us with duplicate vblank events after a suspend/resume
+		// cycle. Recreating the X connection and GLX context seems to fix this.
+		// Oh NVIDIA.
+		log_warn("Duplicate vblank event found with msc %d. Possible NVIDIA bug?", msc);
+		log_warn("Resetting the vblank scheduler");
+		sgi_video_sync_scheduler_deinit(&sched->base);
+		sched->base.vblank_event_requested = false;
+		if (!sgi_video_sync_scheduler_init(&sched->base)) {
+			log_error("Failed to reset the vblank scheduler");
+		} else {
+			sgi_video_sync_scheduler_schedule(&sched->base);
+		}
+		return;
+	}
+	auto event = (struct vblank_event){
+	    .msc = msc,
+	    .ust = atomic_load(&sched->current_ust),
+	};
+	sched->base.vblank_event_requested = false;
+	sched->last_msc = msc;
+	log_verbose("Received vblank event for msc %" PRIu64, event.msc);
+	vblank_scheduler_invoke_callbacks(&sched->base, &event);
+}
+#endif
+
+static bool present_vblank_scheduler_schedule(struct vblank_scheduler *base) {
+	auto self = (struct present_vblank_scheduler *)base;
+	log_verbose("Requesting vblank event for window 0x%08x, msc %" PRIu64,
+	            base->target_window, self->last_msc + 1);
+	assert(!base->vblank_event_requested);
+	x_request_vblank_event(base->c, base->target_window, self->last_msc + 1);
+	base->vblank_event_requested = true;
+	return true;
+}
+
+static void present_vblank_callback(EV_P attr_unused, ev_timer *w, int attr_unused revents) {
+	auto sched = container_of(w, struct present_vblank_scheduler, callback_timer);
+	auto event = (struct vblank_event){
+	    .msc = sched->last_msc,
+	    .ust = sched->last_ust,
+	};
+	sched->base.vblank_event_requested = false;
+	vblank_scheduler_invoke_callbacks(&sched->base, &event);
+}
+
+static bool present_vblank_scheduler_init(struct vblank_scheduler *base) {
+	auto self = (struct present_vblank_scheduler *)base;
+	base->type = VBLANK_SCHEDULER_PRESENT;
+	ev_timer_init(&self->callback_timer, present_vblank_callback, 0, 0);
+
+	self->event_id = x_new_id(base->c);
+	auto select_input =
+	    xcb_present_select_input(base->c->c, self->event_id, base->target_window,
+	                             XCB_PRESENT_EVENT_MASK_COMPLETE_NOTIFY);
+	set_cant_fail_cookie(base->c, select_input);
+	self->event =
+	    xcb_register_for_special_xge(base->c->c, &xcb_present_id, self->event_id, NULL);
+	return true;
+}
+
+static void present_vblank_scheduler_deinit(struct vblank_scheduler *base) {
+	auto self = (struct present_vblank_scheduler *)base;
+	ev_timer_stop(base->loop, &self->callback_timer);
+	auto select_input =
+	    xcb_present_select_input(base->c->c, self->event_id, base->target_window, 0);
+	set_cant_fail_cookie(base->c, select_input);
+	xcb_unregister_for_special_event(base->c->c, self->event);
+}
+
+/// Handle PresentCompleteNotify events
+///
+/// Schedule the registered callback to be called when the current vblank ends.
+static void handle_present_complete_notify(struct present_vblank_scheduler *self,
+                                           xcb_present_complete_notify_event_t *cne) {
+	assert(self->base.type == VBLANK_SCHEDULER_PRESENT);
+
+	if (cne->kind != XCB_PRESENT_COMPLETE_KIND_NOTIFY_MSC) {
+		return;
+	}
+
+	assert(self->base.vblank_event_requested);
+
+	// X sometimes sends duplicate/bogus MSC events, when screen has just been turned
+	// off. Don't use the msc value in these events. We treat this as not receiving a
+	// vblank event at all, and try to get a new one.
+	//
+	// See:
+	// https://gitlab.freedesktop.org/xorg/xserver/-/issues/1418
+	bool event_is_invalid = cne->msc <= self->last_msc || cne->ust == 0;
+	if (event_is_invalid) {
+		log_debug("Invalid PresentCompleteNotify event, %" PRIu64 " %" PRIu64,
+		          cne->msc, cne->ust);
+		x_request_vblank_event(self->base.c, cne->window, self->last_msc + 1);
+		return;
+	}
+
+	self->last_ust = cne->ust;
+	self->last_msc = cne->msc;
+
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+	auto now_us = (unsigned long)(now.tv_sec * 1000000L + now.tv_nsec / 1000);
+	double delay_sec = 0.0;
+	if (now_us < cne->ust) {
+		log_trace("The end of this vblank is %" PRIu64 " us into the "
+		          "future",
+		          cne->ust - now_us);
+		delay_sec = (double)(cne->ust - now_us) / 1000000.0;
+	}
+	// Wait until the end of the current vblank to invoke callbacks. If we
+	// call it too early, it can mistakenly think the render missed the
+	// vblank, and doesn't schedule render for the next vblank, causing frame
+	// drops.
+	assert(!ev_is_active(&self->callback_timer));
+	ev_timer_set(&self->callback_timer, delay_sec, 0);
+	ev_timer_start(self->base.loop, &self->callback_timer);
+}
+
+static bool handle_present_events(struct vblank_scheduler *base) {
+	auto self = (struct present_vblank_scheduler *)base;
+	xcb_present_generic_event_t *ev;
+	while ((ev = (void *)xcb_poll_for_special_event(base->c->c, self->event))) {
+		if (ev->event != self->event_id) {
+			// This event doesn't have the right event context, it's not meant
+			// for us.
+			goto next;
+		}
+
+		// We only subscribed to the complete notify event.
+		assert(ev->evtype == XCB_PRESENT_EVENT_COMPLETE_NOTIFY);
+		handle_present_complete_notify(self, (void *)ev);
+	next:
+		free(ev);
+	}
+	return true;
+}
+
+static const struct vblank_scheduler_ops vblank_scheduler_ops[LAST_VBLANK_SCHEDULER] = {
+    [VBLANK_SCHEDULER_PRESENT] =
+        {
+            .size = sizeof(struct present_vblank_scheduler),
+            .init = present_vblank_scheduler_init,
+            .deinit = present_vblank_scheduler_deinit,
+            .schedule = present_vblank_scheduler_schedule,
+            .handle_x_events = handle_present_events,
+        },
+#ifdef CONFIG_OPENGL
+    [VBLANK_SCHEDULER_SGI_VIDEO_SYNC] =
+        {
+            .size = sizeof(struct sgi_video_sync_vblank_scheduler),
+            .init = sgi_video_sync_scheduler_init,
+            .deinit = sgi_video_sync_scheduler_deinit,
+            .schedule = sgi_video_sync_scheduler_schedule,
+            .handle_x_events = NULL,
+        },
+#endif
+};
+
+static bool vblank_scheduler_schedule_internal(struct vblank_scheduler *self) {
+	assert(self->type < LAST_VBLANK_SCHEDULER);
+	auto fn = vblank_scheduler_ops[self->type].schedule;
+	assert(fn != NULL);
+	return fn(self);
+}
+
+bool vblank_scheduler_schedule(struct vblank_scheduler *self,
+                               vblank_callback_t vblank_callback, void *user_data) {
+	if (self->callback_count == 0 && self->wind_down == 0) {
+		if (!vblank_scheduler_schedule_internal(self)) {
+			return false;
+		}
+	}
+	if (self->callback_count == self->callback_capacity) {
+		size_t new_capacity =
+		    self->callback_capacity ? self->callback_capacity * 2 : 1;
+		void *new_buffer =
+		    realloc(self->callbacks, new_capacity * sizeof(*self->callbacks));
+		if (!new_buffer) {
+			return false;
+		}
+		self->callbacks = new_buffer;
+		self->callback_capacity = new_capacity;
+	}
+	self->callbacks[self->callback_count++] = (struct vblank_closure){
+	    .fn = vblank_callback,
+	    .user_data = user_data,
+	};
+	return true;
+}
+
+static void
+vblank_scheduler_invoke_callbacks(struct vblank_scheduler *self, struct vblank_event *event) {
+	// callbacks might be added during callback invocation, so we need to
+	// copy the callback_count.
+	size_t count = self->callback_count, write_head = 0;
+	if (count == 0) {
+		self->wind_down--;
+	} else {
+		self->wind_down = VBLANK_WIND_DOWN;
+	}
+	for (size_t i = 0; i < count; i++) {
+		auto action = self->callbacks[i].fn(event, self->callbacks[i].user_data);
+		switch (action) {
+		case VBLANK_CALLBACK_AGAIN:
+			if (i != write_head) {
+				self->callbacks[write_head] = self->callbacks[i];
+			}
+			write_head++;
+		case VBLANK_CALLBACK_DONE:
+		default:        // nothing to do
+			break;
+		}
+	}
+	memset(self->callbacks + write_head, 0,
+	       (count - write_head) * sizeof(*self->callbacks));
+	assert(count == self->callback_count && "callbacks should not be added when "
+	                                        "callbacks are being invoked.");
+	self->callback_count = write_head;
+	if (self->callback_count || self->wind_down) {
+		vblank_scheduler_schedule_internal(self);
+	}
+}
+
+void vblank_scheduler_free(struct vblank_scheduler *self) {
+	assert(self->type < LAST_VBLANK_SCHEDULER);
+	auto fn = vblank_scheduler_ops[self->type].deinit;
+	if (fn != NULL) {
+		fn(self);
+	}
+	free(self->callbacks);
+	free(self);
+}
+
+struct vblank_scheduler *
+vblank_scheduler_new(struct ev_loop *loop, struct x_connection *c,
+                     xcb_window_t target_window, enum vblank_scheduler_type type) {
+	size_t object_size = vblank_scheduler_ops[type].size;
+	auto init_fn = vblank_scheduler_ops[type].init;
+	if (!object_size || !init_fn) {
+		log_error("Unsupported or invalid vblank scheduler type: %d", type);
+		return NULL;
+	}
+
+	assert(object_size >= sizeof(struct vblank_scheduler));
+	struct vblank_scheduler *self = calloc(1, object_size);
+	self->target_window = target_window;
+	self->c = c;
+	self->loop = loop;
+	init_fn(self);
+	return self;
+}
+
+bool vblank_handle_x_events(struct vblank_scheduler *self) {
+	assert(self->type < LAST_VBLANK_SCHEDULER);
+	auto fn = vblank_scheduler_ops[self->type].handle_x_events;
+	if (fn != NULL) {
+		return fn(self);
+	}
+	return true;
+}

src/vblank.h

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <xcb/present.h>
+#include <xcb/xcb.h>
+
+#include <ev.h>
+#include <xcb/xproto.h>
+
+#include "config.h"
+#include "x.h"
+
+/// An object that schedule vblank events.
+struct vblank_scheduler;
+
+struct vblank_event {
+	uint64_t msc;
+	uint64_t ust;
+};
+
+enum vblank_callback_action {
+	/// The callback should be called again in the next vblank.
+	VBLANK_CALLBACK_AGAIN,
+	/// The callback is done and should not be called again.
+	VBLANK_CALLBACK_DONE,
+};
+
+typedef enum vblank_callback_action (*vblank_callback_t)(struct vblank_event *event,
+                                                         void *user_data);
+
+/// Schedule a vblank event.
+///
+/// Schedule for `cb` to be called when the current vblank ends. If this is called
+/// from a callback function for the current vblank, the newly scheduled callback
+/// will be called in the next vblank.
+///
+/// Returns whether the scheduling is successful. Scheduling can fail if there
+/// is not enough memory.
+bool vblank_scheduler_schedule(struct vblank_scheduler *self, vblank_callback_t cb,
+                               void *user_data);
+struct vblank_scheduler *
+vblank_scheduler_new(struct ev_loop *loop, struct x_connection *c,
+                     xcb_window_t target_window, enum vblank_scheduler_type type);
+void vblank_scheduler_free(struct vblank_scheduler *);
+
+bool vblank_handle_x_events(struct vblank_scheduler *self);

src/win.c

@@ -73,6 +73,11 @@ static void
 win_update_frame_extents(session_t *ps, struct managed_win *w, xcb_window_t client);
 static void win_update_prop_shadow_raw(session_t *ps, struct managed_win *w);
 static void win_update_prop_shadow(session_t *ps, struct managed_win *w);
+/**
+ * Update window EWMH fullscreen state.
+ */
+bool win_update_prop_fullscreen(struct x_connection *c, const struct atom *atoms,
+                                struct managed_win *w);
 /**
  * Update leader of a window.
  */
@@ -134,10 +139,10 @@ static inline bool attr_pure win_is_real_visible(const struct managed_win *w) {
  * Update focused state of a window.
  */
 static void win_update_focused(session_t *ps, struct managed_win *w) {
-	if (UNSET != w->focused_force) {
+	if (w->focused_force != UNSET) {
 		w->focused = w->focused_force;
 	} else {
-		w->focused = win_is_focused_raw(ps, w);
+		w->focused = win_is_focused_raw(w);
 
 		// Use wintype_focus, and treat WM windows and override-redirected
 		// windows specially
@@ -205,7 +210,7 @@ static inline bool group_is_focused(session_t *ps, xcb_window_t leader) {
 			continue;
 		}
 		auto mw = (struct managed_win *)w;
-		if (win_get_leader(ps, mw) == leader && win_is_focused_raw(ps, mw)) {
+		if (win_get_leader(ps, mw) == leader && win_is_focused_raw(mw)) {
 			return true;
 		}
 	}
@@ -302,6 +307,13 @@ static inline void win_release_pixmap(backend_t *base, struct managed_win *w) {
 		w->flags |= WIN_FLAGS_PIXMAP_NONE;
 	}
 }
+static inline void win_release_oldpixmap(backend_t *base, struct managed_win *w) {
+	log_debug("Releasing old_pixmap of window %#010x (%s)", w->base.id, w->name);
+	if (w->old_win_image) {
+		base->ops->release_image(base, w->old_win_image);
+		w->old_win_image = NULL;
+	}
+}
 static inline void win_release_shadow(backend_t *base, struct managed_win *w) {
 	log_debug("Releasing shadow of window %#010x (%s)", w->base.id, w->name);
 	assert(w->shadow_image);
@@ -398,6 +410,7 @@ void win_release_images(struct backend_base *backend, struct managed_win *w) {
 	if (!win_check_flags_all(w, WIN_FLAGS_PIXMAP_NONE)) {
 		assert(!win_check_flags_all(w, WIN_FLAGS_PIXMAP_STALE));
 		win_release_pixmap(backend, w);
+		win_release_oldpixmap(backend, w);
 	}
 
 	if (!win_check_flags_all(w, WIN_FLAGS_SHADOW_NONE)) {
@@ -457,6 +470,12 @@ static void win_update_properties(session_t *ps, struct managed_win *w) {
 		win_update_prop_shadow(ps, w);
 	}
 
+	if (win_fetch_and_unset_property_stale(w, ps->atoms->a_NET_WM_STATE)) {
+		if (win_update_prop_fullscreen(&ps->c, ps->atoms, w)) {
+			win_set_flags(w, WIN_FLAGS_FACTOR_CHANGED);
+		}
+	}
+
 	if (win_fetch_and_unset_property_stale(w, ps->atoms->aWM_CLIENT_LEADER) ||
 	    win_fetch_and_unset_property_stale(w, ps->atoms->aWM_TRANSIENT_FOR)) {
 		win_update_leader(ps, w);
@@ -465,13 +484,181 @@ static void win_update_properties(session_t *ps, struct managed_win *w) {
 	win_clear_all_properties_stale(w);
 }
 
+static void init_animation(session_t *ps, struct managed_win *w) {
+	CLEAR_MASK(w->animation_is_tag)
+	static int32_t randr_mon_center_x, randr_mon_center_y;
+	if (w->randr_monitor != -1) {
+		auto e = pixman_region32_extents(&ps->monitors.regions[w->randr_monitor]);
+		randr_mon_center_x = (e->x2 + e->x1) / 2, randr_mon_center_y = (e->y2 + e->y1) / 2;
+	} else {
+		randr_mon_center_x = ps->root_width / 2, randr_mon_center_y = ps->root_height / 2;
+	}
+	static double *anim_x, *anim_y, *anim_w, *anim_h;
+	enum open_window_animation animation;
+
+
+	animation = ps->o.animation_for_open_window;
+
+	if (w->window_type != WINTYPE_TOOLTIP &&
+		wid_has_prop(ps, w->client_win, ps->atoms->aWM_TRANSIENT_FOR)) {
+		animation = ps->o.animation_for_transient_window;
+	}
+
+	if (ps->o.wintype_option[w->window_type].animation != OPEN_WINDOW_ANIMATION_INVALID
+		&& !w->dwm_mask) {
+		animation = ps->o.wintype_option[w->window_type].animation;
+	}
+
+	anim_x = &w->animation_center_x, anim_y = &w->animation_center_y;
+	anim_w = &w->animation_w, anim_h = &w->animation_h;
+
+        if (w->dwm_mask & ANIM_PREV_TAG) {
+		animation = ps->o.animation_for_prev_tag;
+
+		if (ps->o.enable_fading_prev_tag) {
+		w->opacity_target_old = fmax(w->opacity_target, w->opacity_target_old);
+		w->state = WSTATE_FADING;
+		w->animation_is_tag |= ANIM_FADE;
+		}
+		if (ps->o.animation_for_prev_tag >= OPEN_WINDOW_ANIMATION_ZOOM) {
+		w->animation_is_tag |= ANIM_FAST;
+		w->dwm_mask |= ANIM_SPECIAL_MINIMIZE;
+		goto revert;
+		}
+		w->animation_is_tag |= ANIM_SLOW;
+        } else if (w->dwm_mask & ANIM_NEXT_TAG) {
+		animation = ps->o.animation_for_next_tag;
+		w->animation_is_tag |= animation >= OPEN_WINDOW_ANIMATION_ZOOM ? ANIM_FAST : ANIM_SLOW;
+		if (ps->o.enable_fading_next_tag) {
+		w->opacity = 0.0;
+		w->state = WSTATE_FADING;
+		}
+        } else if (w->dwm_mask & ANIM_UNMAP) {
+		animation = ps->o.animation_for_unmap_window;
+		revert:
+		anim_x = &w->animation_dest_center_x, anim_y = &w->animation_dest_center_y;
+		anim_w = &w->animation_dest_w, anim_h = &w->animation_dest_h;
+        }
+
+	double angle;
+	switch (animation) {
+	case OPEN_WINDOW_ANIMATION_NONE:  // No animation
+		w->animation_center_x = w->pending_g.x + w->pending_g.width * 0.5;
+		w->animation_center_y = w->pending_g.y + w->pending_g.height * 0.5;
+		w->animation_w = w->pending_g.width;
+		w->animation_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_FLYIN: // Fly-in from a random point outside the screen
+		// Compute random point off screen
+		angle = 2 * M_PI * ((double)rand() / RAND_MAX);
+		const double radius =
+		    sqrt(ps->root_width * ps->root_width + ps->root_height * ps->root_height);
+
+		// Set animation
+		*anim_x = randr_mon_center_x + radius * cos(angle);
+		*anim_y = randr_mon_center_y + radius * sin(angle);
+		*anim_w = 0;
+		*anim_h = 0;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_UP: // Slide up the image, without changing its location
+		*anim_x = w->pending_g.x + w->pending_g.width * 0.5;
+		*anim_y = w->pending_g.y + w->pending_g.height;
+		*anim_w = w->pending_g.width;
+		*anim_h = 0;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_DOWN:  // Slide down the image, without changing its location
+		*anim_x = w->pending_g.x + w->pending_g.width * 0.5;
+		*anim_y = w->pending_g.y;
+		*anim_w = w->pending_g.width;
+		*anim_h = 0;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_LEFT:  // Slide left the image, without changing its location
+		*anim_x = w->pending_g.x + w->pending_g.width;
+		*anim_y = w->pending_g.y + w->pending_g.height * 0.5;
+		*anim_w = 0;
+		*anim_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_RIGHT: // Slide right the image, without changing its location
+		*anim_x = w->pending_g.x;
+		*anim_y = w->pending_g.y + w->pending_g.height * 0.5;
+		*anim_w = 0;
+		*anim_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_IN:
+		*anim_x = w->pending_g.x + w->pending_g.width * 0.5;
+		*anim_y = w->pending_g.y + w->pending_g.height * 0.5;
+		*anim_w = w->pending_g.width;
+		*anim_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_IN_CENTER:
+		*anim_x = randr_mon_center_x;
+		*anim_y = w->g.y + w->pending_g.height * 0.5;
+		*anim_w = w->pending_g.width;
+		*anim_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_OUT:
+		w->animation_dest_center_x = w->pending_g.x + w->pending_g.width * 0.5;
+		w->animation_dest_center_y = w->pending_g.y;
+		w->animation_dest_w = w->pending_g.width;
+		w->animation_dest_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_SLIDE_OUT_CENTER:
+		w->animation_dest_center_x = randr_mon_center_x;
+		w->animation_dest_center_y = w->pending_g.y;
+		w->animation_dest_w = w->pending_g.width;
+		w->animation_dest_h = w->pending_g.height;
+		break;
+	case OPEN_WINDOW_ANIMATION_ZOOM:  // Zoom-in the image, without changing its location
+		if (w->dwm_mask & ANIM_SPECIAL_MINIMIZE) {
+			*anim_x = w->g.x + w->g.width * 0.5;
+			*anim_y = w->g.y + w->g.height * 0.5;
+		} else {
+			*anim_x = w->pending_g.x + w->pending_g.width * 0.5;
+			*anim_y = w->pending_g.y + w->pending_g.height * 0.5;
+		}
+		*anim_w = 0;
+		*anim_h = 0;
+		break;
+	case OPEN_WINDOW_ANIMATION_MINIMIZE:
+		*anim_x = randr_mon_center_x;
+		*anim_y = randr_mon_center_y;
+		*anim_w = 0;
+		*anim_h = 0;
+		break;
+	case OPEN_WINDOW_ANIMATION_SQUEEZE:
+		if (w->dwm_mask & ANIM_PREV_TAG) {
+			*anim_h = 0;
+		} else {
+			*anim_x = w->pending_g.x + w->pending_g.width * 0.5;
+			*anim_y = w->pending_g.y + w->pending_g.height * 0.5;
+			*anim_w = w->pending_g.width;
+			*anim_h = 0;
+		}
+		break;
+	case OPEN_WINDOW_ANIMATION_SQUEEZE_BOTTOM:
+		if (w->dwm_mask & ANIM_PREV_TAG) {
+			*anim_y = w->g.y + w->g.height;
+			*anim_h = 0;
+		} else {
+			w->animation_center_x = w->pending_g.x + w->pending_g.width * 0.5;
+			w->animation_center_y = w->pending_g.y + w->pending_g.height;
+			w->animation_w = w->pending_g.width;
+			*anim_h = 0;
+			*anim_y = w->pending_g.y + w->pending_g.height;
+		}
+		break;
+	case OPEN_WINDOW_ANIMATION_INVALID: assert(false); break;
+	}
+}
+
 /// Handle non-image flags. This phase might set IMAGES_STALE flags
 void win_process_update_flags(session_t *ps, struct managed_win *w) {
 	// Whether the window was visible before we process the mapped flag. i.e.
 	// is the window just mapped.
 	bool was_visible = win_is_real_visible(w);
-	log_trace("Processing flags for window %#010x (%s), was visible: %d", w->base.id,
-	          w->name, was_visible);
+	log_trace("Processing flags for window %#010x (%s), was visible: %d, flags: "
+	          "%#" PRIx64,
+	          w->base.id, w->name, was_visible, w->flags);
 
 	if (win_check_flags_all(w, WIN_FLAGS_MAPPED)) {
 		map_win_start(ps, w);
@@ -505,8 +692,82 @@ void win_process_update_flags(session_t *ps, struct managed_win *w) {
 			add_damage_from_win(ps, w);
 		}
 
-		// Update window geometry
-		w->g = w->pending_g;
+
+
+        // Determine if a window should animate
+		if (win_should_animate(ps, w)) {
+			if (w->pending_g.y < 0 && w->g.y > 0 && abs(w->pending_g.y - w->g.y) >= w->pending_g.height)
+				w->dwm_mask = ANIM_PREV_TAG;
+			else if (w->pending_g.y > 0 && w->g.y < 0 && abs(w->pending_g.y - w->g.y) >= w->pending_g.height)
+				w->dwm_mask = ANIM_NEXT_TAG;
+
+			if (!was_visible || w->dwm_mask) {
+
+				// Set window-open animation
+				init_animation(ps, w);
+				if (!(w->dwm_mask & ANIM_SPECIAL_MINIMIZE)) {
+					w->animation_dest_center_x = w->pending_g.x + w->pending_g.width * 0.5;
+					w->animation_dest_center_y = w->pending_g.y + w->pending_g.height * 0.5;
+					w->animation_dest_w = w->pending_g.width;
+					w->animation_dest_h = w->pending_g.height;
+					w->g.x = (int16_t)round(w->animation_center_x -
+							    w->animation_w * 0.5);
+					w->g.y = (int16_t)round(w->animation_center_y -
+							    w->animation_h * 0.5);
+					w->g.width = (uint16_t)round(w->animation_w);
+					w->g.height = (uint16_t)round(w->animation_h);
+				}
+
+			} else {
+				w->animation_is_tag = ANIM_IN_TAG;
+				w->animation_dest_center_x =
+				    w->pending_g.x + w->pending_g.width * 0.5;
+				w->animation_dest_center_y =
+				    w->pending_g.y + w->pending_g.height * 0.5;
+				w->animation_dest_w = w->pending_g.width;
+				w->animation_dest_h = w->pending_g.height;
+			}
+
+			CLEAR_MASK(w->dwm_mask)
+			w->g.border_width = w->pending_g.border_width;
+			double x_dist = w->animation_dest_center_x - w->animation_center_x;
+			double y_dist = w->animation_dest_center_y - w->animation_center_y;
+			double w_dist = w->animation_dest_w - w->animation_w;
+			double h_dist = w->animation_dest_h - w->animation_h;
+			w->animation_inv_og_distance =
+				1.0 / sqrt(x_dist * x_dist + y_dist * y_dist +
+							w_dist * w_dist + h_dist * h_dist);
+
+			if (isinf(w->animation_inv_og_distance))
+				w->animation_inv_og_distance = 0;
+
+			// We only grab images if w->reg_ignore_valid is true as
+			// there's an ev_shape_notify() event fired quickly on new windows
+			// for e.g. in case of Firefox main menu and ev_shape_notify()
+			// sets the win_set_flags(w, WIN_FLAGS_SIZE_STALE); which
+			// brakes the new image captured and because this same event
+			// also sets w->reg_ignore_valid = false; too we check for it
+			if (w->reg_ignore_valid) {
+				if (w->old_win_image) {
+					ps->backend_data->ops->release_image(ps->backend_data,
+														w->old_win_image);
+					w->old_win_image = NULL;
+				}
+
+				// We only grab
+				if (w->win_image) {
+					w->old_win_image = ps->backend_data->ops->clone_image(
+						ps->backend_data, w->win_image, &w->bounding_shape);
+				}
+			}
+
+		w->animation_progress = 0.0;
+		} else {
+			w->g = w->pending_g;
+		}
+
+		// Whether a window is fullscreen changes based on its geometry
+		win_update_is_fullscreen(ps, w);
 
 		if (win_check_flags_all(w, WIN_FLAGS_SIZE_STALE)) {
 			win_on_win_size_change(ps, w);
@@ -643,12 +904,14 @@ int win_update_name(session_t *ps, struct managed_win *w) {
 		return 0;
 	}
 
-	if (!(wid_get_text_prop(ps, w->client_win, ps->atoms->a_NET_WM_NAME, &strlst, &nstr))) {
+	if (!(wid_get_text_prop(&ps->c, ps->atoms, w->client_win,
+	                        ps->atoms->a_NET_WM_NAME, &strlst, &nstr))) {
 		log_debug("(%#010x): _NET_WM_NAME unset, falling back to "
 		          "WM_NAME.",
 		          w->client_win);
 
-		if (!wid_get_text_prop(ps, w->client_win, ps->atoms->aWM_NAME, &strlst, &nstr)) {
+		if (!wid_get_text_prop(&ps->c, ps->atoms, w->client_win,
+		                       ps->atoms->aWM_NAME, &strlst, &nstr)) {
 			log_debug("Unsetting window name for %#010x", w->client_win);
 			free(w->name);
 			w->name = NULL;
@@ -675,7 +938,8 @@ static int win_update_role(session_t *ps, struct managed_win *w) {
 	char **strlst = NULL;
 	int nstr = 0;
 
-	if (!wid_get_text_prop(ps, w->client_win, ps->atoms->aWM_WINDOW_ROLE, &strlst, &nstr)) {
+	if (!wid_get_text_prop(&ps->c, ps->atoms, w->client_win,
+	                       ps->atoms->aWM_WINDOW_ROLE, &strlst, &nstr)) {
 		return -1;
 	}
 
@@ -818,6 +1082,10 @@ double win_calc_opacity_target(session_t *ps, const struct managed_win *w) {
 	if (w->state == WSTATE_UNMAPPING || w->state == WSTATE_DESTROYING) {
 		return 0;
 	}
+    if ((w->state == WSTATE_FADING && (w->animation_is_tag & ANIM_FADE))) {
+        return 0;
+    }
+
 	// Try obeying opacity property and window type opacity firstly
 	if (w->has_opacity_prop) {
 		opacity = ((double)w->opacity_prop) / OPAQUE;
@@ -828,7 +1096,7 @@ double win_calc_opacity_target(session_t *ps, const struct managed_win *w) {
 	} else {
 		// Respect active_opacity only when the window is physically
 		// focused
-		if (win_is_focused_raw(ps, w)) {
+		if (win_is_focused_raw(w)) {
 			opacity = ps->o.active_opacity;
 		} else if (!w->focused) {
 			// Respect inactive_opacity in some cases
@@ -882,6 +1150,24 @@ bool win_should_fade(session_t *ps, const struct managed_win *w) {
 	return ps->o.wintype_option[w->window_type].fade;
 }
 
+/**
+ * Determine if a window should animate.
+ */
+bool win_should_animate(session_t *ps, const struct managed_win *w) {
+    if (!ps->o.animations) {
+        return false;
+    }
+    if (ps->o.wintype_option[w->window_type].animation == 0) {
+        log_debug("Animation disabled by window_type");
+        return false;
+    }
+    if (c2_match(ps, w, ps->o.animation_blacklist, NULL)) {
+        log_debug("Animation disabled by animation_exclude");
+        return false;
+    }
+    return true;
+}
+
 /**
  * Reread _COMPTON_SHADOW property from a window.
  *
@@ -954,7 +1240,7 @@ static void win_set_shadow(session_t *ps, struct managed_win *w, bool shadow_new
 
 		// Delayed update of shadow image
 		// By setting WIN_FLAGS_SHADOW_STALE, we ask win_process_flags to
-		// re-create or release the shaodw in based on whether w->shadow
+		// re-create or release the shadow in based on whether w->shadow
 		// is set.
 		win_set_flags(w, WIN_FLAGS_SHADOW_STALE);
 
@@ -1011,6 +1297,30 @@ void win_update_prop_shadow(session_t *ps, struct managed_win *w) {
 	}
 }
 
+/**
+ * Update window EWMH fullscreen state.
+ */
+bool win_update_prop_fullscreen(struct x_connection *c, const struct atom *atoms,
+                                struct managed_win *w) {
+	auto prop = x_get_prop(c, w->client_win, atoms->a_NET_WM_STATE, 12, XCB_ATOM_ATOM, 0);
+	if (!prop.nitems) {
+		return false;
+	}
+
+	bool is_fullscreen = false;
+	for (uint32_t i = 0; i < prop.nitems; i++) {
+		if (prop.atom[i] == atoms->a_NET_WM_STATE_FULLSCREEN) {
+			is_fullscreen = true;
+			break;
+		}
+	}
+	free_winprop(&prop);
+
+	bool changed = w->is_ewmh_fullscreen != is_fullscreen;
+	w->is_ewmh_fullscreen = is_fullscreen;
+	return changed;
+}
+
 static void win_determine_clip_shadow_above(session_t *ps, struct managed_win *w) {
 	bool should_crop = (ps->o.wintype_option[w->window_type].clip_shadow_above ||
 	                    c2_match(ps, w, ps->o.shadow_clip_list, NULL));
@@ -1139,19 +1449,19 @@ static void win_determine_blur_background(session_t *ps, struct managed_win *w)
  * Determine if a window should have rounded corners.
  */
 static void win_determine_rounded_corners(session_t *ps, struct managed_win *w) {
-	if (ps->o.corner_radius == 0) {
-		w->corner_radius = 0;
-		return;
-	}
-
 	void *radius_override = NULL;
 	if (c2_match(ps, w, ps->o.corner_radius_rules, &radius_override)) {
 		log_debug("Matched corner rule! %d", w->corner_radius);
 	}
 
+	if (ps->o.corner_radius == 0 && !radius_override) {
+		w->corner_radius = 0;
+		return;
+	}
+
 	// Don't round full screen windows & excluded windows,
 	// unless we find a corner override in corner_radius_rules
-	if (!radius_override && ((w && win_is_fullscreen(ps, w)) ||
+	if (!radius_override && ((w && w->is_fullscreen) ||
 	                         c2_match(ps, w, ps->o.rounded_corners_blacklist, NULL))) {
 		w->corner_radius = 0;
 		log_debug("Not rounding corners for window %#010x", w->base.id);
@@ -1218,9 +1528,10 @@ void win_update_opacity_rule(session_t *ps, struct managed_win *w) {
  */
 void win_on_factor_change(session_t *ps, struct managed_win *w) {
 	log_debug("Window %#010x (%s) factor change", w->base.id, w->name);
-	// Focus needs to be updated first, as other rules might depend on the
-	// focused state of the window
+	// Focus and is_fullscreen needs to be updated first, as other rules might depend
+	// on the focused state of the window
 	win_update_focused(ps, w);
+	win_update_is_fullscreen(ps, w);
 
 	win_determine_shadow(ps, w);
 	win_determine_clip_shadow_above(ps, w);
@@ -1253,6 +1564,10 @@ void win_on_factor_change(session_t *ps, struct managed_win *w) {
  * Update cache data in struct _win that depends on window size.
  */
 void win_on_win_size_change(session_t *ps, struct managed_win *w) {
+	log_trace("Window %#010x (%s) size changed, was %dx%d, now %dx%d", w->base.id,
+	          w->name, w->widthb, w->heightb, w->g.width + w->g.border_width * 2,
+	          w->g.height + w->g.border_width * 2);
+
 	w->widthb = w->g.width + w->g.border_width * 2;
 	w->heightb = w->g.height + w->g.border_width * 2;
 	w->shadow_dx = ps->o.shadow_offset_x;
@@ -1266,8 +1581,12 @@ void win_on_win_size_change(session_t *ps, struct managed_win *w) {
 	       w->state != WSTATE_UNMAPPING);
 
 	// Invalidate the shadow we built
-	win_set_flags(w, WIN_FLAGS_IMAGES_STALE);
-	win_release_mask(ps->backend_data, w);
+	// Do not set flags if window is unmapping and animation is running
+	if (w->state != WSTATE_UNMAPPED && w->state != WSTATE_DESTROYING &&
+	       w->state != WSTATE_UNMAPPING) {
+		win_set_flags(w, WIN_FLAGS_IMAGES_STALE);
+		win_release_mask(ps->backend_data, w);
+	}
 	ps->pending_updates = true;
 	free_paint(ps, &w->shadow_paint);
 }
@@ -1526,14 +1845,19 @@ struct win *fill_win(session_t *ps, struct win *w) {
 	    .blur_background = false,
 	    .reg_ignore = NULL,
 	    // The following ones are updated for other reasons
-	    .pixmap_damaged = false,          // updated by damage events
-	    .state = WSTATE_UNMAPPED,         // updated by window state changes
-	    .in_openclose = true,             // set to false after first map is done,
-	                                      // true here because window is just created
-	    .reg_ignore_valid = false,        // set to true when damaged
-	    .flags = WIN_FLAGS_IMAGES_NONE,        // updated by
-	                                           // property/attributes/etc
-	                                           // change
+	    .pixmap_damaged = false,         // updated by damage events
+	    .state = WSTATE_UNMAPPED,        // updated by window state changes
+	    .in_openclose = true,            // set to false after first map is done,
+	                                     // true here because window is just created
+	    .animation_velocity_x = 0.0,             // updated by window geometry changes
+	    .animation_velocity_y = 0.0,             // updated by window geometry changes
+	    .animation_velocity_w = 0.0,             // updated by window geometry changes
+	    .animation_velocity_h = 0.0,             // updated by window geometry changes
+	    .animation_progress = 1.0,               // updated by window geometry changes
+	    .animation_inv_og_distance = NAN,        // updated by window geometry changes
+	    .reg_ignore_valid = false,               // set to true when damaged
+	    .flags = WIN_FLAGS_IMAGES_NONE,          // updated by property/attributes/etc
+	                                             // change
 	    .stale_props = NULL,
 	    .stale_props_capacity = 0,
 
@@ -1559,6 +1883,7 @@ struct win *fill_win(session_t *ps, struct win *w) {
 	    // have no meaning or have no use until the window
 	    // is mapped
 	    .win_image = NULL,
+	    .old_win_image = NULL,
 	    .shadow_image = NULL,
 	    .mask_image = NULL,
 	    .prev_trans = NULL,
@@ -1718,6 +2043,7 @@ struct win *fill_win(session_t *ps, struct win *w) {
 	    ps->atoms->a_NET_WM_NAME,        ps->atoms->aWM_CLASS,
 	    ps->atoms->aWM_WINDOW_ROLE,      ps->atoms->a_COMPTON_SHADOW,
 	    ps->atoms->aWM_CLIENT_LEADER,    ps->atoms->aWM_TRANSIENT_FOR,
+	    ps->atoms->a_NET_WM_STATE,
 	};
 	win_set_properties_stale(new, init_stale_props, ARR_SIZE(init_stale_props));
 
@@ -1747,7 +2073,7 @@ static inline void win_set_leader(session_t *ps, struct managed_win *w, xcb_wind
 		// Update the old and new window group and active_leader if the
 		// window could affect their state.
 		xcb_window_t cache_leader = win_get_leader(ps, w);
-		if (win_is_focused_raw(ps, w) && cache_leader_old != cache_leader) {
+		if (win_is_focused_raw(w) && cache_leader_old != cache_leader) {
 			ps->active_leader = cache_leader;
 
 			group_on_factor_change(ps, cache_leader_old);
@@ -1831,7 +2157,8 @@ bool win_update_class(session_t *ps, struct managed_win *w) {
 	w->class_general = NULL;
 
 	// Retrieve the property string list
-	if (!wid_get_text_prop(ps, w->client_win, ps->atoms->aWM_CLASS, &strlst, &nstr)) {
+	if (!wid_get_text_prop(&ps->c, ps->atoms, w->client_win, ps->atoms->aWM_CLASS,
+	                       &strlst, &nstr)) {
 		return false;
 	}
 
@@ -1860,7 +2187,7 @@ static void win_on_focus_change(session_t *ps, struct managed_win *w) {
 		xcb_window_t leader = win_get_leader(ps, w);
 
 		// If the window gets focused, replace the old active_leader
-		if (win_is_focused_raw(ps, w) && leader != ps->active_leader) {
+		if (win_is_focused_raw(w) && leader != ps->active_leader) {
 			xcb_window_t active_leader_old = ps->active_leader;
 
 			ps->active_leader = leader;
@@ -1869,7 +2196,7 @@ static void win_on_focus_change(session_t *ps, struct managed_win *w) {
 			group_on_factor_change(ps, leader);
 		}
 		// If the group get unfocused, remove it from active_leader
-		else if (!win_is_focused_raw(ps, w) && leader &&
+		else if (!win_is_focused_raw(w) && leader &&
 		         leader == ps->active_leader && !group_is_focused(ps, leader)) {
 			ps->active_leader = XCB_NONE;
 			group_on_factor_change(ps, leader);
@@ -1882,7 +2209,7 @@ static void win_on_focus_change(session_t *ps, struct managed_win *w) {
 #ifdef CONFIG_DBUS
 	// Send D-Bus signal
 	if (ps->o.dbus) {
-		if (win_is_focused_raw(ps, w)) {
+		if (win_is_focused_raw(w)) {
 			cdbus_ev_win_focusin(ps, &w->base);
 		} else {
 			cdbus_ev_win_focusout(ps, &w->base);
@@ -1900,15 +2227,18 @@ void win_set_focused(session_t *ps, struct managed_win *w) {
 		return;
 	}
 
-	if (win_is_focused_raw(ps, w)) {
+	if (w->is_ewmh_focused) {
+		assert(ps->active_win == w);
 		return;
 	}
 
 	auto old_active_win = ps->active_win;
 	ps->active_win = w;
-	assert(win_is_focused_raw(ps, w));
+	w->is_ewmh_focused = true;
 
 	if (old_active_win) {
+		assert(old_active_win->is_ewmh_focused);
+		old_active_win->is_ewmh_focused = false;
 		win_on_focus_change(ps, old_active_win);
 	}
 	win_on_focus_change(ps, w);
@@ -1981,7 +2311,7 @@ void win_update_bounding_shape(session_t *ps, struct managed_win *w) {
 
 		// Add border width because we are using a different origin.
 		// X thinks the top left of the inner window is the origin
-		// (for the bounding shape, althought xcb_get_geometry thinks
+		// (for the bounding shape, although xcb_get_geometry thinks
 		//  the outer top left (outer means outside of the window
 		//  border) is the origin),
 		// We think the top left of the border is the origin
@@ -2001,14 +2331,12 @@ void win_update_bounding_shape(session_t *ps, struct managed_win *w) {
 
 	// Window shape changed, we should free old wpaint and shadow pict
 	// log_trace("free out dated pict");
-	win_set_flags(w, WIN_FLAGS_IMAGES_STALE);
+	win_set_flags(w, WIN_FLAGS_IMAGES_STALE | WIN_FLAGS_FACTOR_CHANGED);
 	win_release_mask(ps->backend_data, w);
 	ps->pending_updates = true;
 
 	free_paint(ps, &w->paint);
 	free_paint(ps, &w->shadow_paint);
-
-	win_on_factor_change(ps, w);
 }
 
 /**
@@ -2121,17 +2449,31 @@ static void unmap_win_finish(session_t *ps, struct managed_win *w) {
 		// Shadow image can be preserved.
 		if (!win_check_flags_all(w, WIN_FLAGS_PIXMAP_NONE)) {
 			win_release_pixmap(ps->backend_data, w);
+			win_release_oldpixmap(ps->backend_data, w);
 		}
 	} else {
 		assert(!w->win_image);
+		assert(!w->old_win_image);
 		assert(!w->shadow_image);
 	}
 
+	// Force animation to completed position
+	w->animation_velocity_x = 0;
+	w->animation_velocity_y = 0;
+	w->animation_velocity_w = 0;
+	w->animation_velocity_h = 0;
+	w->animation_progress = 1.0;
+
 	free_paint(ps, &w->paint);
 	free_paint(ps, &w->shadow_paint);
 
 	// Try again at binding images when the window is mapped next time
 	win_clear_flags(w, WIN_FLAGS_IMAGE_ERROR);
+
+	// Flag window so that it gets animated when it reapears
+	// in case it wasn't destroyed
+	win_set_flags(w, WIN_FLAGS_POSITION_STALE);
+	win_set_flags(w, WIN_FLAGS_SIZE_STALE);
 }
 
 /// Finish the destruction of a window (e.g. after fading has finished).
@@ -2310,7 +2652,7 @@ bool destroy_win_start(session_t *ps, struct win *w) {
 	HASH_DEL(ps->windows, w);
 
 	if (!w->managed || mw->state == WSTATE_UNMAPPED) {
-		// Window is already unmapped, or is an unmanged window, just
+		// Window is already unmapped, or is an unmanaged window, just
 		// destroy it
 		destroy_win_finish(ps, w);
 		return true;
@@ -2335,6 +2677,13 @@ bool destroy_win_start(session_t *ps, struct win *w) {
 			add_damage_from_win(ps, mw);
 		}
 
+		if (win_check_flags_all(mw, WIN_FLAGS_CLIENT_STALE)) {
+			mw->client_win = mw->base.id;
+			mw->wmwin = !mw->a.override_redirect;
+			log_debug("(%#010x): client self (%s)", mw->base.id,
+			          (mw->wmwin ? "wmwin" : "override-redirected"));
+		}
+
 		// Clear some flags about stale window information. Because now
 		// the window is destroyed, we can't update them anyway.
 		win_clear_flags(mw, WIN_FLAGS_SIZE_STALE | WIN_FLAGS_POSITION_STALE |
@@ -2400,6 +2749,30 @@ void unmap_win_start(session_t *ps, struct managed_win *w) {
 	w->opacity_target_old = fmax(w->opacity_target, w->opacity_target_old);
 	w->opacity_target = win_calc_opacity_target(ps, w);
 
+    if (ps->o.animations && ps->o.animation_for_unmap_window != OPEN_WINDOW_ANIMATION_NONE && ps->o.wintype_option[w->window_type].animation) {
+		w->dwm_mask = ANIM_UNMAP;
+		init_animation(ps, w);
+
+		double x_dist = w->animation_dest_center_x - w->animation_center_x;
+		double y_dist = w->animation_dest_center_y - w->animation_center_y;
+		double w_dist = w->animation_dest_w - w->animation_w;
+		double h_dist = w->animation_dest_h - w->animation_h;
+		w->animation_inv_og_distance =
+			1.0 / sqrt(x_dist * x_dist + y_dist * y_dist +
+						w_dist * w_dist + h_dist * h_dist);
+
+		if (isinf(w->animation_inv_og_distance))
+			w->animation_inv_og_distance = 0;
+
+		w->animation_progress = 0.0;
+
+		if (w->old_win_image) {
+			ps->backend_data->ops->release_image(ps->backend_data,
+												w->old_win_image);
+			w->old_win_image = NULL;
+		}
+    }
+
 #ifdef CONFIG_DBUS
 	// Send D-Bus signal
 	if (ps->o.dbus) {
@@ -2445,7 +2818,7 @@ bool win_check_fade_finished(session_t *ps, struct managed_win *w) {
 ///
 /// @return whether the window is destroyed and freed
 bool win_skip_fading(session_t *ps, struct managed_win *w) {
-	if (w->state == WSTATE_MAPPED || w->state == WSTATE_UNMAPPED) {
+	if ((w->state == WSTATE_MAPPED || w->state == WSTATE_UNMAPPED)) {
 		assert(w->opacity_target == w->opacity);
 		return false;
 	}
@@ -2457,11 +2830,12 @@ bool win_skip_fading(session_t *ps, struct managed_win *w) {
 // TODO(absolutelynothelix): rename to x_update_win_(randr_?)monitor and move to
 // the x.c.
 void win_update_monitor(struct x_monitors *monitors, struct managed_win *mw) {
-	mw->randr_monitor = -1;
 	for (int i = 0; i < monitors->count; i++) {
 		auto e = pixman_region32_extents(&monitors->regions[i]);
-		if (e->x1 <= mw->g.x && e->y1 <= mw->g.y &&
-		    e->x2 >= mw->g.x + mw->widthb && e->y2 >= mw->g.y + mw->heightb) {
+		if (((e->x1 <= mw->g.x || e->x1 <= mw->pending_g.x) &&
+		    (e->x2 >= mw->g.x + mw->widthb || e->x2 >= mw->pending_g.x + mw->widthb)) &&
+		    (e->y1 <= mw->g.y || e->y1 <= mw->pending_g.y) &&
+		    (e->y2 >= mw->g.y + mw->heightb || e->y2 >= mw->pending_g.y + mw->heightb)) {
 			mw->randr_monitor = i;
 			log_debug("Window %#010x (%s), %dx%d+%dx%d, is entirely on the "
 			          "monitor %d (%dx%d+%dx%d)",
@@ -2470,6 +2844,7 @@ void win_update_monitor(struct x_monitors *monitors, struct managed_win *mw) {
 			return;
 		}
 	}
+	mw->randr_monitor = -1;
 	log_debug("Window %#010x (%s), %dx%d+%dx%d, is not entirely on any monitor",
 	          mw->base.id, mw->name, mw->g.x, mw->g.y, mw->widthb, mw->heightb);
 }
@@ -2698,41 +3073,6 @@ struct managed_win *find_managed_window_or_parent(session_t *ps, xcb_window_t wi
 	return (struct managed_win *)w;
 }
 
-/**
- * Check if a rectangle includes the whole screen.
- */
-static inline bool rect_is_fullscreen(const session_t *ps, int x, int y, int wid, int hei) {
-	return (x <= 0 && y <= 0 && (x + wid) >= ps->root_width && (y + hei) >= ps->root_height);
-}
-
-/**
- * Check if a window is fulscreen using EWMH
- *
- * TODO(yshui) cache this property
- */
-static inline bool
-win_is_fullscreen_xcb(xcb_connection_t *c, const struct atom *a, const xcb_window_t w) {
-	xcb_get_property_cookie_t prop =
-	    xcb_get_property(c, 0, w, a->a_NET_WM_STATE, XCB_ATOM_ATOM, 0, 12);
-	xcb_get_property_reply_t *reply = xcb_get_property_reply(c, prop, NULL);
-	if (!reply) {
-		return false;
-	}
-
-	if (reply->length) {
-		xcb_atom_t *val = xcb_get_property_value(reply);
-		for (uint32_t i = 0; i < reply->length; i++) {
-			if (val[i] != a->a_NET_WM_STATE_FULLSCREEN) {
-				continue;
-			}
-			free(reply);
-			return true;
-		}
-	}
-	free(reply);
-	return false;
-}
-
 /// Set flags on a window. Some sanity checks are performed
 void win_set_flags(struct managed_win *w, uint64_t flags) {
 	log_debug("Set flags %" PRIu64 " to window %#010x (%s)", flags, w->base.id, w->name);
@@ -2817,13 +3157,15 @@ bool win_check_flags_all(struct managed_win *w, uint64_t flags) {
  *
  * It's not using w->border_size for performance measures.
  */
-bool win_is_fullscreen(const session_t *ps, const struct managed_win *w) {
-	if (!ps->o.no_ewmh_fullscreen &&
-	    win_is_fullscreen_xcb(ps->c.c, ps->atoms, w->client_win)) {
-		return true;
+void win_update_is_fullscreen(const session_t *ps, struct managed_win *w) {
+	if (!ps->o.no_ewmh_fullscreen && w->is_ewmh_fullscreen) {
+		w->is_fullscreen = true;
+		return;
 	}
-	return rect_is_fullscreen(ps, w->g.x, w->g.y, w->widthb, w->heightb) &&
-	       (!w->bounding_shaped || w->rounded_corners);
+	w->is_fullscreen = w->g.x <= 0 && w->g.y <= 0 &&
+	                   (w->g.x + w->widthb) >= ps->root_width &&
+	                   (w->g.y + w->heightb) >= ps->root_height &&
+	                   (!w->bounding_shaped || w->rounded_corners);
 }
 
 /**
@@ -2849,8 +3191,8 @@ bool win_is_bypassing_compositor(const session_t *ps, const struct managed_win *
  * Check if a window is focused, without using any focus rules or forced focus
  * settings
  */
-bool win_is_focused_raw(const session_t *ps, const struct managed_win *w) {
-	return w->a.map_state == XCB_MAP_STATE_VIEWABLE && ps->active_win == w;
+bool win_is_focused_raw(const struct managed_win *w) {
+	return w->a.map_state == XCB_MAP_STATE_VIEWABLE && w->is_ewmh_focused;
 }
 
 // Find the managed window immediately below `i` in the window stack
@@ -2869,5 +3211,5 @@ win_stack_find_next_managed(const session_t *ps, const struct list_node *w) {
 /// Return whether this window is mapped on the X server side
 bool win_is_mapped_in_x(const struct managed_win *w) {
 	return w->state == WSTATE_MAPPING || w->state == WSTATE_FADING ||
-	       w->state == WSTATE_MAPPED || (w->flags & WIN_FLAGS_MAPPED);
+	       w->state == WSTATE_MAPPED || w->state == WSTATE_DESTROYING || (w->flags & WIN_FLAGS_MAPPED);
 }

src/win.h

@@ -96,13 +96,27 @@ struct win_geometry {
 	uint16_t border_width;
 };
 
+enum {
+    // dwm_mask
+    ANIM_PREV_TAG = 1,
+    ANIM_NEXT_TAG = (1 << 1),
+    ANIM_UNMAP = (1 << 2),
+    ANIM_SPECIAL_MINIMIZE = (1 << 3),
+    // animation_is_tag
+    ANIM_IN_TAG = 1,
+    ANIM_SLOW = (1 << 1),
+    ANIM_FAST = (1 << 2),
+    ANIM_FADE = (1 << 3),
+};
+
 struct managed_win {
 	struct win base;
 	/// backend data attached to this window. Only available when
 	/// `state` is not UNMAPPED
-	void *win_image;
-	void *shadow_image;
-	void *mask_image;
+	image_handle win_image;
+	image_handle old_win_image; // Old window image for interpolating window contents during animations
+	image_handle shadow_image;
+	image_handle mask_image;
 	/// Pointer to the next higher window to paint.
 	struct managed_win *prev_trans;
 	/// Number of windows above this window
@@ -152,6 +166,8 @@ struct managed_win {
 	/// opacity state, window geometry, window mapped/unmapped state,
 	/// window mode of the windows above. DOES NOT INCLUDE the body of THIS WINDOW.
 	/// NULL means reg_ignore has not been calculated for this window.
+        /// 1 = tag prev  , 2 = tag next, 4 = unmap
+	uint32_t dwm_mask;
 	rc_region_t *reg_ignore;
 	/// Whether the reg_ignore of all windows beneath this window are valid
 	bool reg_ignore_valid;
@@ -169,6 +185,24 @@ struct managed_win {
 	bool unredir_if_possible_excluded;
 	/// Whether this window is in open/close state.
 	bool in_openclose;
+	/// Current position and destination, for animation
+	double animation_center_x,      animation_center_y;
+	double animation_dest_center_x, animation_dest_center_y;
+	double animation_w,      animation_h;
+	double animation_dest_w, animation_dest_h;
+	/// Spring animation velocity
+	double animation_velocity_x, animation_velocity_y;
+	double animation_velocity_w, animation_velocity_h;
+	/// Track animation progress; goes from 0 to 1
+	double animation_progress;
+	/// Inverse of the window distance at the start of animation, for
+	/// tracking animation progress
+	double animation_inv_og_distance;
+	/// Animation info if it is a tag change & check if its changing window sizes
+    	/// 0: no tag change
+    	/// 1: normal tag change animation
+    	/// 2: tag change animation that effects window size
+    	uint16_t animation_is_tag;
 
 	// Client window related members
 	/// ID of the top-level client window of the window.
@@ -199,6 +233,14 @@ struct managed_win {
 	char *class_general;
 	/// <code>WM_WINDOW_ROLE</code> value of the window.
 	char *role;
+	/// Whether the window sets the EWMH fullscreen property.
+	bool is_ewmh_fullscreen;
+	/// Whether the window should be considered fullscreen. Based on
+	/// `is_ewmh_fullscreen`, or the windows spatial relation with the
+	/// root window. Which one is used is determined by user configuration.
+	bool is_fullscreen;
+	/// Whether the window is the EWMH active window.
+	bool is_ewmh_focused;
 
 	// Opacity-related members
 	/// Current window opacity.
@@ -244,13 +286,13 @@ struct managed_win {
 	switch_t shadow_force;
 	/// Opacity of the shadow. Affected by window opacity and frame opacity.
 	double shadow_opacity;
-	/// X offset of shadow. Affected by commandline argument.
+	/// X offset of shadow. Affected by command line argument.
 	int shadow_dx;
-	/// Y offset of shadow. Affected by commandline argument.
+	/// Y offset of shadow. Affected by command line argument.
 	int shadow_dy;
-	/// Width of shadow. Affected by window size and commandline argument.
+	/// Width of shadow. Affected by window size and command line argument.
 	int shadow_width;
-	/// Height of shadow. Affected by window size and commandline argument.
+	/// Height of shadow. Affected by window size and command line argument.
 	int shadow_height;
 	/// Picture to render shadow. Affected by window size.
 	paint_t shadow_paint;
@@ -349,6 +391,8 @@ void win_update_monitor(struct x_monitors *monitors, struct managed_win *mw);
  */
 // XXX was win_border_size
 void win_update_bounding_shape(session_t *ps, struct managed_win *w);
+/// Recheck if a window is fullscreen
+void win_update_is_fullscreen(const session_t *ps, struct managed_win *w);
 /**
  * Check if a window has BYPASS_COMPOSITOR property set
  */
@@ -424,17 +468,10 @@ struct managed_win *find_toplevel(session_t *ps, xcb_window_t id);
  */
 struct managed_win *find_managed_window_or_parent(session_t *ps, xcb_window_t wid);
 
-/**
- * Check if a window is a fullscreen window.
- *
- * It's not using w->border_size for performance measures.
- */
-bool attr_pure win_is_fullscreen(const session_t *ps, const struct managed_win *w);
-
 /**
  * Check if a window is focused, without using any focus rules or forced focus settings
  */
-bool attr_pure win_is_focused_raw(const session_t *ps, const struct managed_win *w);
+bool attr_pure win_is_focused_raw(const struct managed_win *w);
 
 /// check if window has ARGB visual
 bool attr_pure win_has_alpha(const struct managed_win *w);
@@ -459,6 +496,9 @@ bool win_check_flags_all(struct managed_win *w, uint64_t flags);
 /// Mark properties as stale for a window
 void win_set_properties_stale(struct managed_win *w, const xcb_atom_t *prop, int nprops);
 
+/// Determine if a window should animate
+bool attr_pure win_should_animate(session_t *ps, const struct managed_win *w);
+
 static inline attr_unused void win_set_property_stale(struct managed_win *w, xcb_atom_t prop) {
 	return win_set_properties_stale(w, (xcb_atom_t[]){prop}, 1);
 }

src/win_defs.h

@@ -68,7 +68,7 @@ typedef enum {
 } winstate_t;
 
 enum win_flags {
-	// Note: *_NONE flags are mostly redudant and meant for detecting logical errors
+	// Note: *_NONE flags are mostly redundant and meant for detecting logical errors
 	// in the code
 
 	/// pixmap is out of date, will be update in win_process_flags

src/x.c

@@ -9,11 +9,14 @@
 #include <pixman.h>
 #include <xcb/composite.h>
 #include <xcb/damage.h>
+#include <xcb/dpms.h>
 #include <xcb/glx.h>
+#include <xcb/present.h>
 #include <xcb/randr.h>
 #include <xcb/render.h>
 #include <xcb/sync.h>
 #include <xcb/xcb.h>
+#include <xcb/xcb_aux.h>
 #include <xcb/xcb_renderutil.h>
 #include <xcb/xfixes.h>
 
@@ -92,7 +95,7 @@ void x_connection_init(struct x_connection *c, Display *dpy) {
 	c->previous_xerror_handler = XSetErrorHandler(xerror);
 
 	c->screen = DefaultScreen(dpy);
-	c->screen_info = x_screen_of_display(c, c->screen);
+	c->screen_info = xcb_aux_get_screen(c->c, c->screen);
 }
 
 /**
@@ -179,10 +182,9 @@ xcb_window_t wid_get_prop_window(struct x_connection *c, xcb_window_t wid, xcb_a
 /**
  * Get the value of a text property of a window.
  */
-bool wid_get_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop, char ***pstrlst,
-                       int *pnstr) {
-	assert(ps->server_grabbed);
-	auto prop_info = x_get_prop_info(&ps->c, wid, prop);
+bool wid_get_text_prop(struct x_connection *c, struct atom *atoms, xcb_window_t wid,
+                       xcb_atom_t prop, char ***pstrlst, int *pnstr) {
+	auto prop_info = x_get_prop_info(c, wid, prop);
 	auto type = prop_info.type;
 	auto format = prop_info.format;
 	auto length = prop_info.length;
@@ -191,8 +193,7 @@ bool wid_get_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop, char **
 		return false;
 	}
 
-	if (type != XCB_ATOM_STRING && type != ps->atoms->aUTF8_STRING &&
-	    type != ps->atoms->aC_STRING) {
+	if (type != XCB_ATOM_STRING && type != atoms->aUTF8_STRING && type != atoms->aC_STRING) {
 		log_warn("Text property %d of window %#010x has unsupported type: %d",
 		         prop, wid, type);
 		return false;
@@ -207,7 +208,7 @@ bool wid_get_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop, char **
 	xcb_generic_error_t *e = NULL;
 	auto word_count = (length + 4 - 1) / 4;
 	auto r = xcb_get_property_reply(
-	    ps->c.c, xcb_get_property(ps->c.c, 0, wid, prop, type, 0, word_count), &e);
+	    c->c, xcb_get_property(c->c, 0, wid, prop, type, 0, word_count), &e);
 	if (!r) {
 		log_debug_x_error(e, "Failed to get window property for %#010x", wid);
 		free(e);
@@ -319,6 +320,17 @@ xcb_visualid_t x_get_visual_for_standard(struct x_connection *c, xcb_pict_standa
 	return x_get_visual_for_pictfmt(g_pictfmts, pictfmt->id);
 }
 
+xcb_visualid_t x_get_visual_for_depth(xcb_screen_t *screen, uint8_t depth) {
+	xcb_depth_iterator_t depth_it = xcb_screen_allowed_depths_iterator(screen);
+	for (; depth_it.rem; xcb_depth_next(&depth_it)) {
+		if (depth_it.data->depth == depth) {
+			return xcb_depth_visuals_iterator(depth_it.data).data->visual_id;
+		}
+	}
+
+	return XCB_NONE;
+}
+
 xcb_render_pictformat_t
 x_get_pictfmt_for_standard(struct x_connection *c, xcb_pict_standard_t std) {
 	x_get_server_pictfmts(c);
@@ -328,24 +340,6 @@ x_get_pictfmt_for_standard(struct x_connection *c, xcb_pict_standard_t std) {
 	return pictfmt->id;
 }
 
-int x_get_visual_depth(struct x_connection *c, xcb_visualid_t visual) {
-	auto setup = xcb_get_setup(c->c);
-	for (auto screen = xcb_setup_roots_iterator(setup); screen.rem;
-	     xcb_screen_next(&screen)) {
-		for (auto depth = xcb_screen_allowed_depths_iterator(screen.data);
-		     depth.rem; xcb_depth_next(&depth)) {
-			const int len = xcb_depth_visuals_length(depth.data);
-			const xcb_visualtype_t *visuals = xcb_depth_visuals(depth.data);
-			for (int i = 0; i < len; i++) {
-				if (visual == visuals[i].visual_id) {
-					return depth.data->depth;
-				}
-			}
-		}
-	}
-	return -1;
-}
-
 xcb_render_picture_t
 x_create_picture_with_pictfmt_and_pixmap(struct x_connection *c,
                                          const xcb_render_pictforminfo_t *pictfmt,
@@ -457,6 +451,34 @@ bool x_fetch_region(struct x_connection *c, xcb_xfixes_region_t r, pixman_region
 	return ret;
 }
 
+bool x_set_region(struct x_connection *c, xcb_xfixes_region_t dst, const region_t *src) {
+	if (!src || dst == XCB_NONE) {
+		return false;
+	}
+
+	int32_t nrects = 0;
+	const rect_t *rects = pixman_region32_rectangles((region_t *)src, &nrects);
+	if (!rects || nrects < 1) {
+		return false;
+	}
+
+	xcb_rectangle_t *xrects = ccalloc(nrects, xcb_rectangle_t);
+	for (int32_t i = 0; i < nrects; i++) {
+		xrects[i] =
+		    (xcb_rectangle_t){.x = to_i16_checked(rects[i].x1),
+		                      .y = to_i16_checked(rects[i].y1),
+		                      .width = to_u16_checked(rects[i].x2 - rects[i].x1),
+		                      .height = to_u16_checked(rects[i].y2 - rects[i].y1)};
+	}
+
+	bool success =
+	    XCB_AWAIT_VOID(xcb_xfixes_set_region, c->c, dst, to_u32_checked(nrects), xrects);
+
+	free(xrects);
+
+	return success;
+}
+
 uint32_t x_create_region(struct x_connection *c, const region_t *reg) {
 	if (!reg) {
 		return XCB_NONE;
@@ -560,9 +582,7 @@ _x_strerror(unsigned long serial, uint8_t major, uint16_t minor, uint8_t error_c
 	const char *name = "Unknown";
 
 #define CASESTRRET(s)                                                                    \
-	case s:                                                                          \
-		name = #s;                                                               \
-		break
+	case s: name = #s; break
 
 #define CASESTRRET2(s)                                                                   \
 	case XCB_##s: name = #s; break
@@ -687,27 +707,6 @@ xcb_pixmap_t x_create_pixmap(struct x_connection *c, uint8_t depth, int width, i
 	return XCB_NONE;
 }
 
-/**
- * Validate a pixmap.
- *
- * Detect whether the pixmap is valid with XGetGeometry. Well, maybe there
- * are better ways.
- */
-bool x_validate_pixmap(struct x_connection *c, xcb_pixmap_t pixmap) {
-	if (pixmap == XCB_NONE) {
-		return false;
-	}
-
-	auto r = xcb_get_geometry_reply(c->c, xcb_get_geometry(c->c, pixmap), NULL);
-	if (!r) {
-		return false;
-	}
-
-	bool ret = r->width && r->height;
-	free(r);
-	return ret;
-}
-
 /// We don't use the _XSETROOT_ID root window property as a source of the background
 /// pixmap because it most likely points to a dummy pixmap used to keep the colormap
 /// associated with the background pixmap alive but we listen for it's changes and update
@@ -777,6 +776,31 @@ err:
 	return false;
 }
 
+void x_request_vblank_event(struct x_connection *c, xcb_window_t window, uint64_t msc) {
+	auto cookie = xcb_present_notify_msc(c->c, window, 0, msc, 1, 0);
+	set_cant_fail_cookie(c, cookie);
+}
+
+static inline bool dpms_screen_is_off(xcb_dpms_info_reply_t *info) {
+	// state is a bool indicating whether dpms is enabled
+	return info->state && (info->power_level != XCB_DPMS_DPMS_MODE_ON);
+}
+
+bool x_check_dpms_status(struct x_connection *c, bool *screen_is_off) {
+	auto r = xcb_dpms_info_reply(c->c, xcb_dpms_info(c->c), NULL);
+	if (!r) {
+		log_error("Failed to query DPMS status.");
+		return false;
+	}
+	auto now_screen_is_off = dpms_screen_is_off(r);
+	if (*screen_is_off != now_screen_is_off) {
+		log_debug("Screen is now %s", now_screen_is_off ? "off" : "on");
+		*screen_is_off = now_screen_is_off;
+	}
+	free(r);
+	return true;
+}
+
 /**
  * Convert a struct conv to a X picture convolution filter, normalizing the kernel
  * in the process. Allow the caller to specify the element at the center of the kernel,
@@ -829,8 +853,8 @@ void x_create_convolution_kernel(const conv *kernel, double center,
 /// Returns {-1, -1, -1, -1, -1, 0} on failure
 struct xvisual_info x_get_visual_info(struct x_connection *c, xcb_visualid_t visual) {
 	auto pictfmt = x_get_pictform_for_visual(c, visual);
-	auto depth = x_get_visual_depth(c, visual);
-	if (!pictfmt || depth == -1) {
+	auto depth = xcb_aux_get_depth_of_visual(c->screen_info, visual);
+	if (!pictfmt || depth == 0) {
 		log_error("Invalid visual %#03x", visual);
 		return (struct xvisual_info){-1, -1, -1, -1, -1, 0};
 	}
@@ -855,19 +879,6 @@ struct xvisual_info x_get_visual_info(struct x_connection *c, xcb_visualid_t vis
 	};
 }
 
-xcb_screen_t *x_screen_of_display(struct x_connection *c, int screen) {
-	xcb_screen_iterator_t iter;
-
-	iter = xcb_setup_roots_iterator(xcb_get_setup(c->c));
-	for (; iter.rem; --screen, xcb_screen_next(&iter)) {
-		if (screen == 0) {
-			return iter.data;
-		}
-	}
-
-	return NULL;
-}
-
 void x_update_monitors(struct x_connection *c, struct x_monitors *m) {
 	x_free_monitor_info(m);
 

src/x.h

@@ -27,6 +27,7 @@ typedef struct winprop {
 		int16_t *p16;
 		int32_t *p32;
 		uint32_t *c32;        // 32bit cardinal
+		xcb_atom_t *atom;
 	};
 	unsigned long nitems;
 	xcb_atom_t type;
@@ -207,17 +208,6 @@ void x_discard_pending(struct x_connection *c, uint32_t sequence);
 /// This function logs X errors, or aborts the program based on severity of the error.
 void x_handle_error(struct x_connection *c, xcb_generic_error_t *ev);
 
-/**
- * Send a request to X server and get the reply to make sure all previous
- * requests are processed, and their replies received
- *
- * xcb_get_input_focus is used here because it is the same request used by
- * libX11
- */
-static inline void x_sync(struct x_connection *c) {
-	free(xcb_get_input_focus_reply(c->c, xcb_get_input_focus(c->c), NULL));
-}
-
 /**
  * Get a specific attribute of a window.
  *
@@ -271,12 +261,11 @@ xcb_window_t wid_get_prop_window(struct x_connection *c, xcb_window_t wid, xcb_a
  *                     array
  * @param[out] pnstr   Number of strings in the array
  */
-bool wid_get_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop, char ***pstrlst,
-                       int *pnstr);
+bool wid_get_text_prop(struct x_connection *c, struct atom *atoms, xcb_window_t wid,
+                       xcb_atom_t prop, char ***pstrlst, int *pnstr);
 
 const xcb_render_pictforminfo_t *
 x_get_pictform_for_visual(struct x_connection *, xcb_visualid_t);
-int x_get_visual_depth(struct x_connection *, xcb_visualid_t);
 
 xcb_render_picture_t
 x_create_picture_with_pictfmt_and_pixmap(struct x_connection *,
@@ -321,6 +310,9 @@ x_create_picture_with_visual(struct x_connection *, int w, int h, xcb_visualid_t
 /// Fetch a X region and store it in a pixman region
 bool x_fetch_region(struct x_connection *, xcb_xfixes_region_t r, region_t *res);
 
+/// Set an X region to a pixman region
+bool x_set_region(struct x_connection *c, xcb_xfixes_region_t dst, const region_t *src);
+
 /// Create a X region from a pixman region
 uint32_t x_create_region(struct x_connection *c, const region_t *reg);
 
@@ -356,8 +348,6 @@ const char *x_strerror(xcb_generic_error_t *e);
 
 xcb_pixmap_t x_create_pixmap(struct x_connection *, uint8_t depth, int width, int height);
 
-bool x_validate_pixmap(struct x_connection *, xcb_pixmap_t pxmap);
-
 /**
  * Free a <code>winprop_t</code>.
  *
@@ -408,14 +398,22 @@ struct xvisual_info x_get_visual_info(struct x_connection *c, xcb_visualid_t vis
 
 xcb_visualid_t x_get_visual_for_standard(struct x_connection *c, xcb_pict_standard_t std);
 
+xcb_visualid_t x_get_visual_for_depth(xcb_screen_t *screen, uint8_t depth);
+
 xcb_render_pictformat_t
 x_get_pictfmt_for_standard(struct x_connection *c, xcb_pict_standard_t std);
 
-xcb_screen_t *x_screen_of_display(struct x_connection *c, int screen);
-
 /// Populates a `struct x_monitors` with the current monitor configuration.
 void x_update_monitors(struct x_connection *, struct x_monitors *);
 /// Free memory allocated for a `struct x_monitors`.
 void x_free_monitor_info(struct x_monitors *);
 
 uint32_t attr_deprecated xcb_generate_id(xcb_connection_t *c);
+
+/// Ask X server to send us a notification for the next end of vblank.
+void x_request_vblank_event(struct x_connection *c, xcb_window_t window, uint64_t msc);
+
+/// Update screen_is_off to reflect the current DPMS state.
+///
+/// Returns true if the DPMS state was successfully queried, false otherwise.
+bool x_check_dpms_status(struct x_connection *c, bool *screen_is_off);

subprojects/test.h/test.h

@@ -58,6 +58,14 @@ struct test_file_metadata __attribute__((weak)) * test_file_head;
 		}                                                                        \
 	} while (0)
 
+#define TEST_NOTEQUAL(a, b)                                                              \
+	do {                                                                             \
+		if ((a) == (b)) {                                                        \
+			SET_FAILURE(#a " == " #b, false);                                \
+			return;                                                          \
+		}                                                                        \
+	} while (0)
+
 #define TEST_TRUE(a)                                                                     \
 	do {                                                                             \
 		if (!(a)) {                                                              \
@@ -69,11 +77,13 @@ struct test_file_metadata __attribute__((weak)) * test_file_head;
 #define TEST_STREQUAL(a, b)                                                              \
 	do {                                                                             \
 		if (strcmp(a, b) != 0) {                                                 \
-			const char *part2 = " != " #b;                                   \
-			size_t len = strlen(a) + strlen(part2) + 3;                      \
-			char *buf = malloc(len);                                         \
-			snprintf(buf, len, "\"%s\"%s", a, part2);                        \
-			SET_FAILURE(buf, true);                                          \
+			const char *test_strequal__part2 = " != " #b;                    \
+			size_t test_strequal__len =                                      \
+			    strlen(a) + strlen(test_strequal__part2) + 3;                \
+			char *test_strequal__buf = malloc(test_strequal__len);           \
+			snprintf(test_strequal__buf, test_strequal__len, "\"%s\"%s", a,  \
+			         test_strequal__part2);                                  \
+			SET_FAILURE(test_strequal__buf, true);                           \
 			return;                                                          \
 		}                                                                        \
 	} while (0)
@@ -81,11 +91,27 @@ struct test_file_metadata __attribute__((weak)) * test_file_head;
 #define TEST_STRNEQUAL(a, b, len)                                                        \
 	do {                                                                             \
 		if (strncmp(a, b, len) != 0) {                                           \
-			const char *part2 = " != " #b;                                   \
-			size_t len2 = len + strlen(part2) + 3;                           \
-			char *buf = malloc(len2);                                        \
-			snprintf(buf, len2, "\"%.*s\"%s", (int)len, a, part2);           \
-			SET_FAILURE(buf, true);                                          \
+			const char *test_strnequal__part2 = " != " #b;                   \
+			size_t test_strnequal__len2 =                                    \
+			    len + strlen(test_strnequal__part2) + 3;                     \
+			char *test_strnequal__buf = malloc(test_strnequal__len2);        \
+			snprintf(test_strnequal__buf, test_strnequal__len2,              \
+			         "\"%.*s\"%s", (int)len, a, test_strnequal__part2);      \
+			SET_FAILURE(test_strnequal__buf, true);                          \
+			return;                                                          \
+		}                                                                        \
+	} while (0)
+
+#define TEST_STREQUAL3(str, expected, len)                                               \
+	do {                                                                             \
+		if (len != strlen(expected) || strncmp(str, expected, len) != 0) {       \
+			const char *test_strequal3__part2 = " != " #expected;            \
+			size_t test_strequal3__len2 =                                    \
+			    len + strlen(test_strequal3__part2) + 3;                     \
+			char *test_strequal3__buf = malloc(test_strequal3__len2);        \
+			snprintf(test_strequal3__buf, test_strequal3__len2,              \
+			         "\"%.*s\"%s", (int)len, str, test_strequal3__part2);    \
+			SET_FAILURE(test_strequal3__buf, true);                          \
 			return;                                                          \
 		}                                                                        \
 	} while (0)
@@ -199,6 +225,9 @@ static inline void __attribute__((constructor(102))) run_tests(void) {
 #define TEST_EQUAL(a, b)                                                                 \
 	(void)(a);                                                                       \
 	(void)(b)
+#define TEST_NOTEQUAL(a, b)                                                              \
+	(void)(a);                                                                       \
+	(void)(b)
 #define TEST_TRUE(a) (void)(a)
 #define TEST_STREQUAL(a, b)                                                              \
 	(void)(a);                                                                       \
@@ -207,5 +236,8 @@ static inline void __attribute__((constructor(102))) run_tests(void) {
 	(void)(a);                                                                       \
 	(void)(b);                                                                       \
 	(void)(len)
-
+#define TEST_STREQUAL3(str, expected, len)                                               \
+	(void)(str);                                                                     \
+	(void)(expected);                                                                \
+	(void)(len)
 #endif