fix #2884:

crashed when two map renderers are simultaneously rendering the layers
for the canvas and overview (eg. on resize, when overview is docked).
This might fix it.

git-svn-id: http://svn.osgeo.org/qgis/trunk@15050 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/core/qgsmaprenderer.cpp

@@ -38,8 +38,7 @@
 #include <QListIterator>
 #include <QSettings>
 #include <QTime>
-#include "qgslogger.h"
-
+#include <QCoreApplication>
 
 QgsMapRenderer::QgsMapRenderer()
 {
@@ -229,14 +228,22 @@ void QgsMapRenderer::render( QPainter* painter )
     return;
   }
 
-  if ( mDrawing )
+  QPaintDevice* thePaintDevice = painter->device();
+  if ( !thePaintDevice )
   {
     return;
   }
 
-  QPaintDevice* thePaintDevice = painter->device();
-  if ( !thePaintDevice )
+  // wait
+  if( mDrawing )
   {
+    QgsDebugMsg( "already rendering" );
+    QCoreApplication::processEvents();
+  }
+
+  if( mDrawing )
+  {
+    QgsDebugMsg( "still rendering - skipping" );
     return;
   }
 
@@ -599,7 +606,6 @@ void QgsMapRenderer::render( QPainter* painter )
   QgsDebugMsg( "Rendering completed in (seconds): " + QString( "%1" ).arg( renderTime.elapsed() / 1000.0 ) );
 
   mDrawing = false;
-
 }
 
 void QgsMapRenderer::setMapUnits( QGis::UnitType u )
@@ -1073,3 +1079,5 @@ void QgsMapRenderer::setLabelingEngine( QgsLabelingEngineInterface* iface )
 
   mLabelingEngine = iface;
 }
+
+bool QgsMapRenderer::mDrawing = false;

src/core/qgsmaprenderer.h

@@ -249,7 +249,7 @@ class CORE_EXPORT QgsMapRenderer : public QObject
   protected:
 
     //! indicates drawing in progress
-    bool mDrawing;
+    static bool mDrawing;
 
     //! map units per pixel
     double mMapUnitsPerPixel;

src/gui/qgsmapcanvas.cpp

@@ -932,52 +932,59 @@ void QgsMapCanvas::mouseReleaseEvent( QMouseEvent * e )
 
 void QgsMapCanvas::resizeEvent( QResizeEvent * e )
 {
-  static bool isAlreadyIn = false;
-  static QSize lastSize = QSize( -1, -1 );
-
-  lastSize = e->size();
+  mNewSize = e->size();
+}
 
-  if ( isAlreadyIn || mDrawing )
+void QgsMapCanvas::paintEvent( QPaintEvent *e )
+{
+  if( mNewSize.isValid() )
   {
-    //cancel current render progress
-    if ( mMapRenderer )
+    static bool isAlreadyIn = false;
+    static QSize lastSize = QSize();
+
+    lastSize = mNewSize;
+    mNewSize = QSize();
+
+    if ( isAlreadyIn || mDrawing )
     {
-      QgsRenderContext* theRenderContext = mMapRenderer->rendererContext();
-      if ( theRenderContext )
+      //cancel current render progress
+      if ( mMapRenderer )
       {
-        theRenderContext->setRenderingStopped( true );
+        QgsRenderContext* theRenderContext = mMapRenderer->rendererContext();
+        if ( theRenderContext )
+        {
+          theRenderContext->setRenderingStopped( true );
+        }
       }
+      return;
     }
-    return;
-  }
-  isAlreadyIn = true;
+    isAlreadyIn = true;
 
-  while ( lastSize != QSize( -1, -1 ) )
-  {
-    int width = lastSize.width();
-    int height = lastSize.height();
-    lastSize = QSize( -1, -1 );
+    while ( lastSize.isValid() )
+    {
+      int width = lastSize.width();
+      int height = lastSize.height();
+      lastSize = QSize();
 
-    //set map size before scene size helps keep scene indexes updated properly
-    // this was the cause of rubberband artifacts
-    mMap->resize( QSize( width, height ) );
-    mScene->setSceneRect( QRectF( 0, 0, width, height ) );
+      //set map size before scene size helps keep scene indexes updated properly
+      // this was the cause of rubberband artifacts
+      mMap->resize( QSize( width, height ) );
+      mScene->setSceneRect( QRectF( 0, 0, width, height ) );
 
-    // notify canvas items of change
-    updateCanvasItemPositions();
+      // notify canvas items of change
+      updateCanvasItemPositions();
 
-    updateScale();
-#if QT_VERSION >= 0x40600
-    // FIXME: temporary workaround for #2714
-    QTimer::singleShot( 1, this, SLOT( refresh() ) );
-#else
-    refresh();
-#endif
-    emit extentsChanged();
-  }
+      updateScale();
+
+      refresh();
+
+      emit extentsChanged();
+    }
   isAlreadyIn = false;
-} // resizeEvent
+  }
 
+  QGraphicsView::paintEvent( e );
+} // paintEvent
 
 void QgsMapCanvas::updateCanvasItemPositions()
 {

src/gui/qgsmapcanvas.h

@@ -368,6 +368,9 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     //! Overridden resize event
     void resizeEvent( QResizeEvent * e );
 
+    //! Overridden paint event
+    void paintEvent( QPaintEvent * e );
+
     //! called when panning is in action, reset indicates end of panning
     void moveCanvasContents( bool reset = false );
 
@@ -451,6 +454,9 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     //! Mouse wheel action
     WheelAction mWheelAction;
 
+    //! resize canvas size
+    QSize mNewSize;
+
 }; // class QgsMapCanvas
 
 

src/gui/qgsmapoverviewcanvas.cpp

@@ -85,9 +85,21 @@ QgsMapOverviewCanvas::~QgsMapOverviewCanvas()
 
 void QgsMapOverviewCanvas::resizeEvent( QResizeEvent* e )
 {
-  mPixmap = QPixmap( e->size() );
-  mMapRenderer->setOutputSize( e->size(), mPixmap.logicalDpiX() );
-  refresh();
+  mNewSize = e->size();
+}
+
+void QgsMapOverviewCanvas::paintEvent( QPaintEvent* pe )
+{
+  if( mNewSize.isValid() )
+  {
+    mPixmap = QPixmap( mNewSize );
+    mMapRenderer->setOutputSize( mNewSize, mPixmap.logicalDpiX() );
+    mNewSize = QSize();
+    refresh();
+  }
+
+  QPainter paint( this );
+  paint.drawPixmap( pe->rect().topLeft(), mPixmap, pe->rect() );
 }
 
 
@@ -233,16 +245,9 @@ void QgsMapOverviewCanvas::updatePanningWidget( const QPoint& pos )
 }
 
 
-void QgsMapOverviewCanvas::paintEvent( QPaintEvent * pe )
-{
-  QPainter paint( this );
-  paint.drawPixmap( pe->rect().topLeft(), mPixmap, pe->rect() );
-}
-
-
 void QgsMapOverviewCanvas::refresh()
 {
-  if ( mPixmap.isNull() )
+  if ( mPixmap.isNull() || mPixmap.paintingActive() )
     return;
 
   mPixmap.fill( mBgColor ); //palette().color(backgroundRole());

src/gui/qgsmapoverviewcanvas.h

@@ -108,6 +108,9 @@ class GUI_EXPORT QgsMapOverviewCanvas : public QWidget
 
     //! indicates whether antialiasing will be used for rendering
     bool mAntiAliasing;
+
+    //! resized canvas size
+    QSize mNewSize;
 };
 
 #endif