move the optimal extent calculation for a point layer to its own method

qgis · Sep 21, 2020 · b47346b · b47346b
1 parent dd19040
commit b47346b
Show file tree

Hide file tree

Showing 2 changed files with 41 additions and 25 deletions.
diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
@@ -1240,33 +1240,13 @@ void QgsMapCanvas::clearExtentHistory()
   emit zoomNextStatusChanged( mLastExtentIndex < mLastExtent.size() - 1 );
 }// clearExtentHistory
 
-void QgsMapCanvas::zoomToSelected( QgsVectorLayer *layer )
+QgsRectangle QgsMapCanvas::optimalExtentForPointLayer( QgsVectorLayer *layer, const QgsPointXY &center, int scaleFactor )
 {
-  if ( !layer )
-  {
-    // use current layer by default
-    layer = qobject_cast<QgsVectorLayer *>( mCurrentLayer );
-  }
-
-  if ( !layer || !layer->isSpatial() || layer->selectedFeatureCount() == 0 )
-    return;
-
-  QgsRectangle rect = layer->boundingBoxOfSelected();
-  if ( rect.isNull() )
-  {
-    emit messageEmitted( tr( "Cannot zoom to selected feature(s)" ), tr( "No extent could be determined." ), Qgis::Warning );
-    return;
-  }
-
-  rect = mapSettings().layerExtentToOutputExtent( layer, rect );
+  QgsRectangle rect( center, center );
 
-  // zoom in if point cannot be distinguished from others
-  // also check that rect is empty, as it might not in case of multi points
-  if ( layer->geometryType() == QgsWkbTypes::PointGeometry && rect.isEmpty() )
+  if ( layer->geometryType() == QgsWkbTypes::PointGeometry )
   {
-    int scaleFactor = 5;
-    QgsPointXY centerMapCoordinates = rect.center();
-    QgsPointXY centerLayerCoordinates = mSettings.mapToLayerCoordinates( layer, centerMapCoordinates );
+    QgsPointXY centerLayerCoordinates = mSettings.mapToLayerCoordinates( layer, center );
     QgsRectangle extentRect = mSettings.mapToLayerCoordinates( layer, extent() ).scaled( 1.0 / scaleFactor, &centerLayerCoordinates );
     QgsFeatureRequest req = QgsFeatureRequest().setFilterRect( extentRect ).setLimit( 1000 ).setNoAttributes();
     QgsFeatureIterator fit = layer->getFeatures( req );
@@ -1288,10 +1268,38 @@ void QgsMapCanvas::zoomToSelected( QgsVectorLayer *layer )
     {
       // combine selected point with closest point and scale this rect
       rect.combineExtentWith( mSettings.layerToMapCoordinates( layer, closestPoint ) );
-      rect.scale( scaleFactor, &centerMapCoordinates );
+      rect.scale( scaleFactor, &center );
     }
   }
+  return rect;
+}
+
+void QgsMapCanvas::zoomToSelected( QgsVectorLayer *layer )
+{
+  if ( !layer )
+  {
+    // use current layer by default
+    layer = qobject_cast<QgsVectorLayer *>( mCurrentLayer );
+  }
+
+  if ( !layer || !layer->isSpatial() || layer->selectedFeatureCount() == 0 )
+    return;
+
+  QgsRectangle rect = layer->boundingBoxOfSelected();
+  if ( rect.isNull() )
+  {
+    emit messageEmitted( tr( "Cannot zoom to selected feature(s)" ), tr( "No extent could be determined." ), Qgis::Warning );
+    return;
+  }
+
+  rect = mapSettings().layerExtentToOutputExtent( layer, rect );
 
+  // zoom in if point cannot be distinguished from others
+  // also check that rect is empty, as it might not in case of multi points
+  if ( layer->geometryType() == QgsWkbTypes::PointGeometry && rect.isEmpty() )
+  {
+    rect = optimalExtentForPointLayer( layer, rect.center() );
+  }
   zoomToFeatureExtent( rect );
 }
 

diff --git a/src/gui/qgsmapcanvas.h b/src/gui/qgsmapcanvas.h
@@ -1265,6 +1265,14 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     */
     bool boundingBoxOfFeatureIds( const QgsFeatureIds &ids, QgsVectorLayer *layer, QgsRectangle &bbox, QString &errorMsg ) const;
 
+    /**
+     * Rerturns the optimal extent for a point \a layer and a given \a center point in canvas CRS.
+     * This will return an extent combined of the center and the closest point in the layer.
+     * The extent can be scaled with a \a scale factor.
+     * The returned extent might be an empty rect if it cannot be determnined.
+     */
+    QgsRectangle optimalExtentForPointLayer( QgsVectorLayer *layer, const QgsPointXY &center, int scaleFactor = 5 );
+
     void setLayersPrivate( const QList<QgsMapLayer *> &layers );
 
     void startPreviewJobs();