Merge pull request #9839 from wonder-sk/fix-3d-extra-terrain-updates

[3d] Fix unnecessary terrain map updates when changing 3D renderer

python/gui/auto_generated/qgsmaplayerconfigwidget.sip.in

@@ -36,6 +36,15 @@ A panel widget that can be shown in the map style dock
    Keep the loading light as possible for speed in the UI.
 %End
 
+    virtual bool shouldTriggerLayerRepaint() const;
+%Docstring
+Whether this config widget changes map layer properties in a way that triggerRepaint() should
+be called for the layer after applying changes. This is true by default, but some config widgets
+(for example 3D rendering config) do not need layer repaint as they do not modify 2D map rendering.
+
+.. versionadded:: 3.8
+%End
+
   public slots:
 
     virtual void apply() = 0;

src/app/3d/qgsvectorlayer3drendererwidget.h

@@ -66,6 +66,9 @@ class QgsVectorLayer3DRendererWidget : public QgsMapLayerConfigWidget
 
     void setDockMode( bool dockMode ) override;
 
+    //! Only modifies 3D renderer so we do not want layer repaint (which would trigger unnecessary terrain map update)
+    bool shouldTriggerLayerRepaint() const override { return false; }
+
   public slots:
     void apply() override;
 

src/app/qgslayerstylingwidget.cpp

@@ -272,6 +272,7 @@ void QgsLayerStylingWidget::apply()
   QWidget *current = mWidgetStack->mainPanel();
 
   bool styleWasChanged = false;
+  bool triggerRepaint = false;  // whether the change needs the layer to be repainted
   if ( QgsLabelingWidget *widget = qobject_cast<QgsLabelingWidget *>( current ) )
   {
     widget->apply();
@@ -287,31 +288,34 @@ void QgsLayerStylingWidget::apply()
       QgsRendererAbstractMetadata *m = QgsApplication::rendererRegistry()->rendererMetadata( layer->renderer()->type() );
       undoName = QStringLiteral( "Style Change - %1" ).arg( m->visibleName() );
       styleWasChanged = true;
+      triggerRepaint = true;
     }
   }
   else if ( QgsRasterTransparencyWidget *widget = qobject_cast<QgsRasterTransparencyWidget *>( current ) )
   {
     widget->apply();
     styleWasChanged = true;
+    triggerRepaint = true;
   }
   else if ( qobject_cast<QgsRasterHistogramWidget *>( current ) )
   {
     mRasterStyleWidget->apply();
     styleWasChanged = true;
+    triggerRepaint = true;
   }
   else if ( QgsMapLayerConfigWidget *widget = qobject_cast<QgsMapLayerConfigWidget *>( current ) )
   {
     widget->apply();
     styleWasChanged = true;
+    triggerRepaint = widget->shouldTriggerLayerRepaint();
   }
 
-  pushUndoItem( undoName );
+  pushUndoItem( undoName, triggerRepaint );
 
   if ( styleWasChanged )
   {
     emit styleChanged( mCurrentLayer );
     QgsProject::instance()->setDirty( true );
-    mCurrentLayer->triggerRepaint();
   }
   connect( mCurrentLayer, &QgsMapLayer::styleChanged, this, &QgsLayerStylingWidget::updateCurrentWidgetLayer );
 }
@@ -609,25 +613,26 @@ void QgsLayerStylingWidget::liveApplyToggled( bool value )
   settings.setValue( QStringLiteral( "UI/autoApplyStyling" ), value );
 }
 
-void QgsLayerStylingWidget::pushUndoItem( const QString &name )
+void QgsLayerStylingWidget::pushUndoItem( const QString &name, bool triggerRepaint )
 {
   QString errorMsg;
   QDomDocument doc( QStringLiteral( "style" ) );
   QDomElement rootNode = doc.createElement( QStringLiteral( "qgis" ) );
   doc.appendChild( rootNode );
   mCurrentLayer->writeStyle( rootNode, doc, errorMsg, QgsReadWriteContext() );
-  mCurrentLayer->undoStackStyles()->push( new QgsMapLayerStyleCommand( mCurrentLayer, name, rootNode, mLastStyleXml ) );
+  mCurrentLayer->undoStackStyles()->push( new QgsMapLayerStyleCommand( mCurrentLayer, name, rootNode, mLastStyleXml, triggerRepaint ) );
   // Override the last style on the stack
   mLastStyleXml = rootNode.cloneNode();
 }
 
 
-QgsMapLayerStyleCommand::QgsMapLayerStyleCommand( QgsMapLayer *layer, const QString &text, const QDomNode &current, const QDomNode &last )
+QgsMapLayerStyleCommand::QgsMapLayerStyleCommand( QgsMapLayer *layer, const QString &text, const QDomNode &current, const QDomNode &last, bool triggerRepaint )
   : QUndoCommand( text )
   , mLayer( layer )
   , mXml( current )
   , mLastState( last )
   , mTime( QTime::currentTime() )
+  , mTriggerRepaint( triggerRepaint )
 {
 }
 
@@ -636,7 +641,8 @@ void QgsMapLayerStyleCommand::undo()
   QString error;
   QgsReadWriteContext context = QgsReadWriteContext();
   mLayer->readStyle( mLastState, error, context );
-  mLayer->triggerRepaint();
+  if ( mTriggerRepaint )
+    mLayer->triggerRepaint();
 }
 
 void QgsMapLayerStyleCommand::redo()
@@ -644,7 +650,8 @@ void QgsMapLayerStyleCommand::redo()
   QString error;
   QgsReadWriteContext context = QgsReadWriteContext();
   mLayer->readStyle( mXml, error, context );
-  mLayer->triggerRepaint();
+  if ( mTriggerRepaint )
+    mLayer->triggerRepaint();
 }
 
 bool QgsMapLayerStyleCommand::mergeWith( const QUndoCommand *other )
@@ -665,6 +672,7 @@ bool QgsMapLayerStyleCommand::mergeWith( const QUndoCommand *other )
 
   mXml = otherCmd->mXml;
   mTime = otherCmd->mTime;
+  mTriggerRepaint |= otherCmd->mTriggerRepaint;
   return true;
 }
 

src/app/qgslayerstylingwidget.h

@@ -56,7 +56,7 @@ class APP_EXPORT QgsLayerStyleManagerWidgetFactory : public QgsMapLayerConfigWid
 class APP_EXPORT QgsMapLayerStyleCommand : public QUndoCommand
 {
   public:
-    QgsMapLayerStyleCommand( QgsMapLayer *layer, const QString &text, const QDomNode &current, const QDomNode &last );
+    QgsMapLayerStyleCommand( QgsMapLayer *layer, const QString &text, const QDomNode &current, const QDomNode &last, bool triggerRepaint = true );
 
     /**
      * Returns unique ID for this kind of undo command.
@@ -75,6 +75,7 @@ class APP_EXPORT QgsMapLayerStyleCommand : public QUndoCommand
     QDomNode mXml;
     QDomNode mLastState;
     QTime mTime;
+    bool mTriggerRepaint = true;
 };
 
 class APP_EXPORT QgsLayerStylingWidget : public QWidget, private Ui::QgsLayerStylingWidgetBase
@@ -129,7 +130,7 @@ class APP_EXPORT QgsLayerStylingWidget : public QWidget, private Ui::QgsLayerSty
     void liveApplyToggled( bool value );
 
   private:
-    void pushUndoItem( const QString &name );
+    void pushUndoItem( const QString &name, bool triggerRepaint = true );
     int mNotSupportedPage;
     int mLayerPage;
     QTimer *mAutoApplyTimer = nullptr;

src/gui/qgsmaplayerconfigwidget.h

@@ -45,6 +45,14 @@ class GUI_EXPORT QgsMapLayerConfigWidget : public QgsPanelWidget
        */
     QgsMapLayerConfigWidget( QgsMapLayer *layer, QgsMapCanvas *canvas, QWidget *parent = nullptr );
 
+    /**
+     * Whether this config widget changes map layer properties in a way that triggerRepaint() should
+     * be called for the layer after applying changes. This is true by default, but some config widgets
+     * (for example 3D rendering config) do not need layer repaint as they do not modify 2D map rendering.
+     * \since QGIS 3.8
+     */
+    virtual bool shouldTriggerLayerRepaint() const { return true; }
+
   public slots:
 
     /**