More efficient canvas features flash

python/gui/qgsmapcanvas.sip

@@ -244,7 +244,28 @@ Pan to the selected features of current (vector) layer keeping same extent.
  The ``startColor`` and ``endColor`` can be specified, along with the number of
  ``flashes`` and ``duration`` of each flash (in milliseconds).
 
+.. note::
+
+   If the features or geometries are already available, flashGeometries() is much more efficient.
+
 .. versionadded:: 3.0
+.. seealso:: flashGeometries()
+%End
+
+    void flashGeometries( QgsVectorLayer *layer, const QList< QgsGeometry > &geometries,
+                          const QColor &startColor = QColor( 255, 0, 0, 255 ), const QColor &endColor = QColor( 255, 0, 0, 0 ),
+                          int flashes = 3, int duration = 500 );
+%Docstring
+ Causes a set of ``geometries`` to flash within the canvas.
+
+ If ``layer`` is non-null, the geometries will be automatically transformed from the layer
+ CRS to canvas CRS.
+
+ The ``startColor`` and ``endColor`` can be specified, along with the number of
+ ``flashes`` and ``duration`` of each flash (in milliseconds).
+
+.. versionadded:: 3.0
+.. seealso:: flashFeatureIds()
 %End
 
     void setMapTool( QgsMapTool *mapTool );

src/app/qgsselectbyformdialog.cpp

@@ -119,23 +119,23 @@ void QgsSelectByFormDialog::flashFeatures( const QString &filter )
   QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
 
   QgsFeatureRequest request = QgsFeatureRequest().setFilterExpression( filter )
-                              .setFlags( QgsFeatureRequest::NoGeometry )
                               .setExpressionContext( context )
                               .setSubsetOfAttributes( QgsAttributeList() );
 
   QgsFeatureIterator features = mLayer->getFeatures( request );
   QgsFeature feat;
-  QgsFeatureIds ids;
+  QList< QgsGeometry > geoms;
   while ( features.nextFeature( feat ) )
   {
-    ids.insert( feat.id() );
+    if ( feat.hasGeometry() )
+      geoms << feat.geometry();
   }
 
   QgsSettings settings;
   int timeout = settings.value( QStringLiteral( "qgis/messageTimeout" ), 5 ).toInt();
-  if ( !ids.empty() )
+  if ( !geoms.empty() )
   {
-    mMapCanvas->flashFeatureIds( mLayer, ids );
+    mMapCanvas->flashGeometries( mLayer, geoms );
   }
   else if ( mMessageBar )
   {

src/gui/qgsmapcanvas.cpp

@@ -1078,12 +1078,17 @@ void QgsMapCanvas::flashFeatureIds( QgsVectorLayer *layer, const QgsFeatureIds &
     geoms << fet.geometry();
   }
 
-  if ( geoms.isEmpty() )
+  flashGeometries( layer, geoms, color1, color2, flashes, duration );
+}
+
+void QgsMapCanvas::flashGeometries( QgsVectorLayer *layer, const QList<QgsGeometry> &geometries, const QColor &color1, const QColor &color2, int flashes, int duration )
+{
+  if ( geometries.isEmpty() )
     return;
 
-  QgsWkbTypes::GeometryType geomType = QgsWkbTypes::geometryType( layer->wkbType() );
+  QgsWkbTypes::GeometryType geomType = QgsWkbTypes::geometryType( geometries.at( 0 ).wkbType() );
   QgsRubberBand *rb = new QgsRubberBand( this, geomType );
-  for ( const QgsGeometry &geom : qgsAsConst( geoms ) )
+  for ( const QgsGeometry &geom : geometries )
     rb->addGeometry( geom, layer );
 
   if ( geomType == QgsWkbTypes::LineGeometry || geomType == QgsWkbTypes::PointGeometry )

src/gui/qgsmapcanvas.h

@@ -243,12 +243,31 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
      * The \a startColor and \a endColor can be specified, along with the number of
      * \a flashes and \a duration of each flash (in milliseconds).
      *
+     * \note If the features or geometries are already available, flashGeometries() is much more efficient.
+     *
      * \since QGIS 3.0
+     * \see flashGeometries()
      */
     void flashFeatureIds( QgsVectorLayer *layer, const QgsFeatureIds &ids,
                           const QColor &startColor = QColor( 255, 0, 0, 255 ), const QColor &endColor = QColor( 255, 0, 0, 0 ),
                           int flashes = 3, int duration = 500 );
 
+    /**
+     * Causes a set of \a geometries to flash within the canvas.
+     *
+     * If \a layer is non-null, the geometries will be automatically transformed from the layer
+     * CRS to canvas CRS.
+     *
+     * The \a startColor and \a endColor can be specified, along with the number of
+     * \a flashes and \a duration of each flash (in milliseconds).
+     *
+     * \since QGIS 3.0
+     * \see flashFeatureIds()
+     */
+    void flashGeometries( QgsVectorLayer *layer, const QList< QgsGeometry > &geometries,
+                          const QColor &startColor = QColor( 255, 0, 0, 255 ), const QColor &endColor = QColor( 255, 0, 0, 0 ),
+                          int flashes = 3, int duration = 500 );
+
     //! \brief Sets the map tool currently being used on the canvas
     void setMapTool( QgsMapTool *mapTool );