test that window handle actually exists (avoid crash in tests)

3nids · 3nids · commit c1ce03cd3b1e · 2018-10-19T13:46:01.000-04:00
diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
@@ -173,7 +173,8 @@ QgsMapCanvas::QgsMapCanvas( QWidget *parent )
 
   // keep device pixel ratio up to date on screen or resolution change
   connect( window()->windowHandle(), &QWindow::screenChanged, this, [ = ]( QScreen * ) {mSettings.setDevicePixelRatio( devicePixelRatio() );} );
-  connect( window()->windowHandle()->screen(), &QScreen::physicalDotsPerInchChanged, [ = ]( qreal ) {mSettings.setDevicePixelRatio( devicePixelRatio() );} );
+  if ( window()->windowHandle() )
+    connect( window()->windowHandle()->screen(), &QScreen::physicalDotsPerInchChanged, [ = ]( qreal ) {mSettings.setDevicePixelRatio( devicePixelRatio() );} );
 
   connect( &mMapUpdateTimer, &QTimer::timeout, this, &QgsMapCanvas::mapUpdateTimeout );
   mMapUpdateTimer.setInterval( 250 );
