Add initial code

nativeeventfilter.cpp

@@ -0,0 +1,61 @@
+#include "nativeeventfilter.h"
+#include <QVector>
+#include <QX11Info>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <xcb/xcb.h>
+
+namespace {
+    Display * display;        // Connection to X11
+    Window win;               // Grab window
+    int keycode;
+    QVector<quint32> maskModifiers;
+}
+
+NativeEventFilter::NativeEventFilter(QObject *parent) : QObject(parent) {
+    display = QX11Info::display();
+    win = DefaultRootWindow(display);
+    maskModifiers << 0 << Mod2Mask << LockMask << (Mod2Mask | LockMask);
+    setShortcut();
+}
+
+bool NativeEventFilter::nativeEventFilter(const QByteArray &eventType, void *message, long *result) {
+    Q_UNUSED(eventType)
+    Q_UNUSED(result)
+
+    xcb_key_press_event_t *keyEvent;
+
+    // Check xcb event
+    if (eventType == "xcb_generic_event_t") {
+        // cast message xcb event
+        xcb_generic_event_t *event = static_cast<xcb_generic_event_t *>(message);
+
+        // check key press
+        if ((event->response_type & 127) == XCB_KEY_PRESS){
+
+            keyEvent = static_cast<xcb_key_press_event_t *>(message);
+
+            foreach (quint32 maskMods, maskModifiers) {
+                if((keyEvent->state == maskMods)
+                        &&  keyEvent->detail == keycode){
+                    emit activated();
+                    return true;
+                }
+            }
+        }
+    }
+    return false;
+}
+
+void NativeEventFilter::setShortcut() {
+    keycode = XKeysymToKeycode(display, XK_Print);
+    foreach (quint32 maskMods, maskModifiers) {
+        XGrabKey(display,
+                 keycode ,
+                 maskMods,
+                 win,
+                 True,
+                 GrabModeAsync,
+                 GrabModeAsync);
+    }
+}