QNX: Fix screen rotation

The behavior introduced by qtdeclarative's 475d1ed4f6a2 mandates that an
expose event follows a geometry change event. The fix for this uncovered a bug
on the raster backing store which caused the rotation to break on QtWidgets.
The problem was rooted on the assumption that the
QQnxRasterBackingStore::flush() method was only called after paints to the
backing store surface, which was discovered to be a false assumption. Flushing
the backing store can occur in other circunstances, which are out of scope on
the context of the QNX plugin.

Task-number: QTBUG-31329
Change-Id: Icfc3e85324f5a8745f6b5f189f27f8b763f770c7
Reviewed-by: Kevin Krammer <kevin.krammer@kdab.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp b/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp
index 7204e5bce9..6a7a4d0944 100644
--- a/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp
+++ b/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp
@@ -81,6 +81,12 @@ void QQnxRasterBackingStore::flush(QWindow *window, const QRegion &region, const
 {
     qRasterBackingStoreDebug() << Q_FUNC_INFO << "w =" << this->window();
 
+    // Sometimes this method is called even though there is nothing to be
+    // flushed, for instance, after an expose event directly follows a
+    // geometry change event.
+    if (!m_hasUnflushedPaintOperations)
+            return;
+
     QQnxWindow *targetWindow = 0;
     if (window)
         targetWindow = static_cast<QQnxWindow *>(window->handle());
@@ -117,7 +123,6 @@ void QQnxRasterBackingStore::flush(QWindow *window, const QRegion &region, const
 
         // We assume that the TLW has been flushed previously and that no changes were made to the
         // backing store inbetween (### does Qt guarantee this?)
-        Q_ASSERT(!m_hasUnflushedPaintOperations);
 
         targetWindow->adjustBufferSize();
         targetWindow->blitFrom(platformWindow, offset, region);