Parent:     9934c075 (QML: do not check stack size if stack grows up)
Author:     David Edmundson <davidedmundson@kde.org>
AuthorDate: 2015-04-23 15:01:24 +0200
Commit:     David Edmundson <davidedmundson@kde.org>
CommitDate: 2015-04-23 15:05:32 +0200

Avoid calling potentially pure virtual method

In Qt 5.4 screenChanged is called indirectly from the destructor of
QPlatformScreen. By comparing new values against the oldScreen we call
call virtual methods of QPlatformScreen from it's own destructor which
results in a crash.

This patch simply emits change signals whenever a screen change regardless
of whether the value differs from the previous screen. Arguably less
efficient, but better than crashing.

This fix is not needed in Qt 5.5 where the QPA architecture has changed.

Task-number: QTBUG-45753
Change-Id: Ic155906928855a377add9b21bff9e72b31f4667e
---

diff --git a/src/quick/items/qquickscreen.cpp b/src/quick/items/qquickscreen.cpp
index 8ac5a1e..c19841f 100644
--- a/src/quick/items/qquickscreen.cpp
+++ b/src/quick/items/qquickscreen.cpp
@@ -347,24 +347,15 @@ void QQuickScreenAttached::screenChanged
             emit orientationUpdateMaskChanged();
         }
 
-        if (!oldScreen || screen->size() != oldScreen->size()) {
-            emit widthChanged();
-            emit heightChanged();
-        }
-        if (!oldScreen || screen->name() != oldScreen->name())
-            emit nameChanged();
-        if (!oldScreen || screen->orientation() != oldScreen->orientation())
-            emit orientationChanged();
-        if (!oldScreen || screen->primaryOrientation() != oldScreen->primaryOrientation())
-            emit primaryOrientationChanged();
-        if (!oldScreen || screen->availableVirtualGeometry() != oldScreen->availableVirtualGeometry())
-            emit desktopGeometryChanged();
-        if (!oldScreen || screen->logicalDotsPerInch() != oldScreen->logicalDotsPerInch())
-            emit logicalPixelDensityChanged();
-        if (!oldScreen || screen->physicalDotsPerInch() != oldScreen->physicalDotsPerInch())
-            emit pixelDensityChanged();
-        if (!oldScreen || screen->devicePixelRatio() != oldScreen->devicePixelRatio())
-            emit devicePixelRatioChanged();
+        emit widthChanged();
+        emit heightChanged();
+        emit nameChanged();
+        emit orientationChanged();
+        emit primaryOrientationChanged();
+        emit desktopGeometryChanged();
+        emit logicalPixelDensityChanged();
+        emit pixelDensityChanged();
+        emit devicePixelRatioChanged();
 
         connect(screen, SIGNAL(geometryChanged(QRect)),
                 this, SIGNAL(widthChanged()));