Fix screenForGeometry on a corner case

QRect only deals with integers, and I had a window set on the corner and
without a size. When this screen was created, it was reported to be on the
wrong screen, thus created there wrong.
The reason for this is that ::center is not prepared for this use.
QRect(QPoint(500,500), QSize()).center() is QRect(499, 499)

Change-Id: I24e57182f84873306f180749e96368d6da1147a9
Reviewed-by: Paul Olav Tvete <paul.tvete@theqtcompany.com>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/gui/kernel/qplatformwindow.cpp b/src/gui/kernel/qplatformwindow.cpp
index ea3b75c81c..8757715c0d 100644
--- a/src/gui/kernel/qplatformwindow.cpp
+++ b/src/gui/kernel/qplatformwindow.cpp
@@ -484,7 +484,9 @@ QPlatformScreen *QPlatformWindow::screenForGeometry(const QRect &newGeometry) co
 {
     QPlatformScreen *currentScreen = screen();
     QPlatformScreen *fallback = currentScreen;
-    QPoint center = newGeometry.center();
+    //QRect::center can return a value outside the rectangle if it's empty
+    const QPoint center = newGeometry.isEmpty() ? newGeometry.topLeft() : newGeometry.center();
+
     if (!parent() && currentScreen && !currentScreen->geometry().contains(center)) {
         Q_FOREACH (QPlatformScreen* screen, currentScreen->virtualSiblings()) {
             if (screen->geometry().contains(center))