iOS: Don't recreate paint device on beginPaint()

This causes painting errors. Use one lazily-created
device that is used for the lifetime of the backing
store.

Change-Id: Ib36b6f1d6c9f958304dc8403cf17e5d71136469a
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/plugins/platforms/ios/qiosbackingstore.mm b/src/plugins/platforms/ios/qiosbackingstore.mm
index 71f14fdd91..6cefc03377 100644
--- a/src/plugins/platforms/ios/qiosbackingstore.mm
+++ b/src/plugins/platforms/ios/qiosbackingstore.mm
@@ -60,6 +60,7 @@ QIOSBackingStore::QIOSBackingStore(QWindow *window)
 QIOSBackingStore::~QIOSBackingStore()
 {
     delete m_context;
+    delete m_device;
 }
 
 void QIOSBackingStore::beginPaint(const QRegion &)
@@ -68,7 +69,8 @@ void QIOSBackingStore::beginPaint(const QRegion &)
     window()->setSurfaceType(QSurface::OpenGLSurface);
 
     m_context->makeCurrent(window());
-    m_device = new QOpenGLPaintDevice(window()->size());
+    if (!m_device)
+        m_device = new QOpenGLPaintDevice(window()->size());
 }
 
 QPaintDevice *QIOSBackingStore::paintDevice()
@@ -86,8 +88,6 @@ void QIOSBackingStore::flush(QWindow *window, const QRegion &region, const QPoin
 
 void QIOSBackingStore::endPaint()
 {
-    delete m_device;
-
     // Calling makeDone() on the context here would be an option,
     // but is not needed, and would actually add some overhead.
 }