Currently there is some inconsistency in how image_op is implemented
across backends. The glx backend applies some of the image operations
lazily, and not always in the order the operations were made; while the
xrender backend applies the operations eagerly. This can lead to
different render result in some cases.
Instead of trying to preserving the order of operations, which would be
unnecessary, we re-model the API to better reflect the implementation.
We make it clear that setting the property doesn't change the image
data, and properties are only applied during composition and in a
specific order.
This makes sure the render result looks consistent across backends.
Should also improve the performance of the xrender backend, even if only
slightly.
Also distill out the property management code so they can be shared.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
**Work-in-Progress**
Generate suitable parameters for dual-filter kawase blur based on the
selected `blur-strength` or approximate a gauss blur with the selected
`blur-size` and std-deviation.
This commit introduced a new, modular backend interface. The interface
is not very good, since I don't think I fully understand all the
requirements writing a backend have. But this is a good first step.
This commit also includes an initial xrender backend written using the
new interface, and some opengl backend related helper functions, which
are taken from the old opengl backend.
However, there is not integration with the core compton yet. compton
will still use the old backend code. This commit is here so we can get
the automated build test.
What is implemented in the new xrender backend:
* Windows with transparency
* Shadow
* Opacity
* Wallpaper (getting the root pixmap)
* Blur
Known problem with the xrender backend:
* It is slower
Things that still need to be figured out:
* What is the better way to add vsync to the new backends
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
