Add convenience function for checking screen changes to QPlatformWindow.

Add function returning the screen for a new geometry for geometry
change events. This ensures that the checking is done in platform
screen coordinates (which might differ from QScreen coordinates
due to high-DPI changes) and also that no screen changes are
emitted for child windows.

Change-Id: I406750f59f006f834c386d09c0c85a804014924a
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 0cc8c8dbfe..578b4d6ec1 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -1842,14 +1842,10 @@ void QXcbWindow::handleConfigureNotifyEvent(const xcb_configure_notify_event_t *
     QPlatformWindow::setGeometry(rect);
     QWindowSystemInterface::handleGeometryChange(window(), rect);
 
-    if (!m_screen->availableGeometry().intersects(rect)) {
-        Q_FOREACH (QPlatformScreen* screen, m_screen->virtualSiblings()) {
-            if (screen->availableGeometry().intersects(rect)) {
-                m_screen = static_cast<QXcbScreen*>(screen);
-                QWindowSystemInterface::handleWindowScreenChanged(window(), m_screen->QPlatformScreen::screen());
-                break;
-            }
-        }
+    QPlatformScreen *newScreen = screenForGeometry(rect);
+    if (newScreen != m_screen) {
+        m_screen = static_cast<QXcbScreen*>(newScreen);
+        QWindowSystemInterface::handleWindowScreenChanged(window(), newScreen->screen());
     }
 
     m_configureNotifyPending = false;