Ensure all canvases are refreshed when project properties are applied

Author: nyalldawson

src/app/qgisapp.cpp

@@ -3129,7 +3129,6 @@ QgsMapCanvas *QgisApp::createNewMapCanvas( const QString &name )
 
   mapCanvas->setLayers( mMapCanvas->layers() );
   mapCanvas->setExtent( mMapCanvas->extent() );
-  mapCanvas->setCachingEnabled( true );
 
   mapCanvas->setDestinationCrs( QgsProject::instance()->crs() );
 
@@ -10609,11 +10608,6 @@ void QgisApp::projectProperties()
            &QgsStatusBarScaleWidget::updateScales );
   QApplication::restoreOverrideCursor();
 
-  //pass any refresh signals off to canvases
-  // Line below was commented out by wonder three years ago (r4949).
-  // It is needed to refresh scale bar after changing display units.
-  connect( pp, SIGNAL( refresh() ), mMapCanvas, SLOT( refresh() ) );
-
   // Display the modal dialog box.
   pp->exec();
 
@@ -10626,7 +10620,7 @@ void QgisApp::projectProperties()
 
   // delete the property sheet object
   delete pp;
-} // QgisApp::projectProperties
+}
 
 
 QgsClipboard *QgisApp::clipboard()

src/app/qgsprojectproperties.cpp

@@ -812,21 +812,25 @@ void QgsProjectProperties::apply()
   }
 
   //set the color for selections
-  QColor myColor = pbnSelectionColor->color();
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorRedPart" ), myColor.red() );
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorGreenPart" ), myColor.green() );
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorBluePart" ), myColor.blue() );
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorAlphaPart" ), myColor.alpha() );
-  mMapCanvas->setSelectionColor( myColor );
+  QColor selectionColor = pbnSelectionColor->color();
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorRedPart" ), selectionColor.red() );
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorGreenPart" ), selectionColor.green() );
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorBluePart" ), selectionColor.blue() );
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/SelectionColorAlphaPart" ), selectionColor.alpha() );
+
 
   //set the color for canvas
-  myColor = pbnCanvasColor->color();
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/CanvasColorRedPart" ), myColor.red() );
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/CanvasColorGreenPart" ), myColor.green() );
-  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/CanvasColorBluePart" ), myColor.blue() );
-  mMapCanvas->setCanvasColor( myColor );
-  QgisApp::instance()->mapOverviewCanvas()->setBackgroundColor( myColor );
-  QgisApp::instance()->mapOverviewCanvas()->refresh();
+  QColor canvasColor = pbnCanvasColor->color();
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/CanvasColorRedPart" ), canvasColor.red() );
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/CanvasColorGreenPart" ), canvasColor.green() );
+  QgsProject::instance()->writeEntry( QStringLiteral( "Gui" ), QStringLiteral( "/CanvasColorBluePart" ), canvasColor.blue() );
+
+  Q_FOREACH ( QgsMapCanvas *canvas, QgisApp::instance()->mapCanvases() )
+  {
+    canvas->setCanvasColor( canvasColor );
+    canvas->setSelectionColor( selectionColor );
+  }
+  QgisApp::instance()->mapOverviewCanvas()->setBackgroundColor( canvasColor );
 
   //save project scales
   QStringList myScales;
@@ -1140,7 +1144,12 @@ void QgsProjectProperties::apply()
   //save variables
   QgsProject::instance()->setCustomVariables( mVariableEditor->variablesInActiveScope() );
 
-  emit refresh();
+  //refresh canvases to reflect new properties, eg background color and scale bar after changing display units.
+  Q_FOREACH ( QgsMapCanvas *canvas, QgisApp::instance()->mapCanvases() )
+  {
+    canvas->refresh();
+  }
+  QgisApp::instance()->mapOverviewCanvas()->refresh();
 }
 
 void QgsProjectProperties::showProjectionsTab()

src/app/qgsprojectproperties.h

@@ -162,9 +162,6 @@ class APP_EXPORT QgsProjectProperties : public QgsOptionsDialogBase, private Ui:
     //! Signal used to inform listeners that project scale list may have changed
     void scalesChanged( const QStringList &scales = QStringList() );
 
-    //! let listening canvases know to refresh
-    void refresh();
-
   private:
 
     //! Formats for displaying coordinates

src/gui/qgsmapcanvas.cpp

@@ -1544,7 +1544,6 @@ void QgsMapCanvas::unsetMapTool( QgsMapTool *tool )
   }
 }
 
-//! Write property of QColor bgColor.
 void QgsMapCanvas::setCanvasColor( const QColor &color )
 {
   // background of map's pixmap
@@ -1561,7 +1560,7 @@ void QgsMapCanvas::setCanvasColor( const QColor &color )
 
   // background of QGraphicsScene
   mScene->setBackgroundBrush( bgBrush );
-} // setBackgroundColor
+}
 
 QColor QgsMapCanvas::canvasColor() const
 {