lazily determine full canvas extent

qgis · Mar 3, 2016 · c87529e · c87529e
1 parent f722bb2
commit c87529e
Show file tree

Hide file tree

Showing 3 changed files with 22 additions and 10 deletions.
diff --git a/src/core/qgsmaprenderer.cpp b/src/core/qgsmaprenderer.cpp
@@ -58,6 +58,7 @@ QgsMapRenderer::QgsMapRenderer()
   mDestCRS = new QgsCoordinateReferenceSystem( GEOCRS_ID, QgsCoordinateReferenceSystem::InternalCrsId ); //WGS 84
 
   mOutputUnits = QgsMapRenderer::Millimeters;
+  mFullExtent.setMinimal();
 
   mLabelingEngine = nullptr;
 }
@@ -928,15 +929,19 @@ QgsRectangle QgsMapRenderer::mapToLayerCoordinates( QgsMapLayer* theLayer, QgsRe
   return rect;
 }
 
-
 void QgsMapRenderer::updateFullExtent()
+{
+  mFullExtent.setMinimal();
+}
+
+QgsRectangle QgsMapRenderer::fullExtent()
 {
   QgsDebugMsg( "called." );
-  QgsMapLayerRegistry* registry = QgsMapLayerRegistry::instance();
 
-  // reset the map canvas extent since the extent may now be smaller
-  // We can't use a constructor since QgsRectangle normalizes the rectangle upon construction
-  mFullExtent.setMinimal();
+  if ( !mFullExtent.isNull() )
+    return mFullExtent;
+
+  QgsMapLayerRegistry* registry = QgsMapLayerRegistry::instance();
 
   // iterate through the map layers and test each layers extent
   // against the current min and max values
@@ -993,11 +998,7 @@ void QgsMapRenderer::updateFullExtent()
   }
 
   QgsDebugMsg( "Full extent: " + mFullExtent.toString() );
-}
 
-QgsRectangle QgsMapRenderer::fullExtent()
-{
-  updateFullExtent();
   return mFullExtent;
 }
 
@@ -1013,7 +1014,6 @@ QStringList& QgsMapRenderer::layerSet()
   return mLayerSet;
 }
 
-
 bool QgsMapRenderer::readXML( QDomNode & theNode )
 {
   QgsMapSettings tmpSettings;

diff --git a/src/gui/qgsmapoverviewcanvas.cpp b/src/gui/qgsmapoverviewcanvas.cpp
@@ -62,6 +62,12 @@ void QgsMapOverviewCanvas::resizeEvent( QResizeEvent* e )
   QWidget::resizeEvent( e );
 }
 
+void QgsMapOverviewCanvas::showEvent( QShowEvent* e )
+{
+  refresh();
+  QWidget::showEvent( e );
+}
+
 void QgsMapOverviewCanvas::paintEvent( QPaintEvent* pe )
 {
   if ( !mPixmap.isNull() )
@@ -155,6 +161,9 @@ void QgsMapOverviewCanvas::updatePanningWidget( QPoint pos )
 
 void QgsMapOverviewCanvas::refresh()
 {
+  if ( !isVisible() )
+    return;
+
   updateFullExtent();
 
   if ( !mSettings.hasValidSettings() )

diff --git a/src/gui/qgsmapoverviewcanvas.h b/src/gui/qgsmapoverviewcanvas.h
@@ -81,6 +81,9 @@ class GUI_EXPORT QgsMapOverviewCanvas : public QWidget
     //! Overridden paint event
     void paintEvent( QPaintEvent * pe ) override;
 
+    //! Overridden show event
+    void showEvent( QShowEvent * e ) override;
+
     //! Overridden resize event
     void resizeEvent( QResizeEvent * e ) override;