Client: Fix regression; drawing decorations of active windows as inactive

We can't trust QWindow::isActive, because it relies on focusWindow, which may
be updated too late, and there might also be multiple active toplevel windows
at once on Wayland. Even though Qt doesn't support multiple seats, we should
still draw the decorations of active windows correctly.

This implements QPlatformWindow::isActive and uses it in the decorations.

Change-Id: I34d79b354e2d26694533e2319a26f24085212243
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

src/plugins/platforms/wayland/plugins/decorations/bradient/main.cpp

@@ -132,6 +132,7 @@ QMargins QWaylandBradientDecoration::margins() const
 
 void QWaylandBradientDecoration::paint(QPaintDevice *device)
 {
+    bool active = window()->handle()->isActive();
     QRect surfaceRect(QPoint(), window()->frameGeometry().size());
     QRect clips[] =
     {
@@ -183,7 +184,7 @@ void QWaylandBradientDecoration::paint(QPaintDevice *device)
 
         p.save();
         p.setClipRect(titleBar);
-        p.setPen(window()->isActive() ? m_foregroundColor : m_foregroundInactiveColor);
+        p.setPen(active ? m_foregroundColor : m_foregroundInactiveColor);
         QSizeF size = m_windowTitle.size();
         int dx = (top.width() - size.width()) /2;
         int dy = (top.height()- size.height()) /2;
@@ -199,7 +200,7 @@ void QWaylandBradientDecoration::paint(QPaintDevice *device)
     QRectF rect;
 
     // Default pen
-    QPen pen(window()->isActive() ? m_foregroundColor : m_foregroundInactiveColor);
+    QPen pen(active ? m_foregroundColor : m_foregroundInactiveColor);
     p.setPen(pen);
 
     // Close button

src/plugins/platforms/wayland/qwaylanddisplay.cpp

@@ -413,6 +413,11 @@ void QWaylandDisplay::setLastInputDevice(QWaylandInputDevice *device, uint32_t s
     mLastInputWindow = win;
 }
 
+bool QWaylandDisplay::isWindowActivated(const QWaylandWindow *window)
+{
+    return mActiveWindows.contains(const_cast<QWaylandWindow *>(window));
+}
+
 void QWaylandDisplay::handleWindowActivated(QWaylandWindow *window)
 {
     if (mActiveWindows.contains(window))

src/plugins/platforms/wayland/qwaylanddisplay_p.h

@@ -176,6 +176,7 @@ public:
     QWaylandWindow *lastInputWindow() const;
     void setLastInputDevice(QWaylandInputDevice *device, uint32_t serial, QWaylandWindow *window);
 
+    bool isWindowActivated(const QWaylandWindow *window);
     void handleWindowActivated(QWaylandWindow *window);
     void handleWindowDeactivated(QWaylandWindow *window);
     void handleKeyboardFocusChanged(QWaylandInputDevice *inputDevice);

src/plugins/platforms/wayland/qwaylandwindow.cpp

@@ -943,6 +943,11 @@ bool QWaylandWindow::isExposed() const
     return QPlatformWindow::isExposed();
 }
 
+bool QWaylandWindow::isActive() const
+{
+    return mDisplay->isWindowActivated(this);
+}
+
 int QWaylandWindow::scale() const
 {
     return mScale;

src/plugins/platforms/wayland/qwaylandwindow_p.h

@@ -146,6 +146,7 @@ public:
 
     void requestActivateWindow() override;
     bool isExposed() const override;
+    bool isActive() const override;
     void unfocus();
 
     QWaylandAbstractDecoration *decoration() const;