Make map tool snap to grid crs aware

m-kuhn · m-kuhn · commit 9e387e48fc85 · 2018-08-26T14:10:46.000+02:00
diff --git a/python/gui/auto_generated/qgsmapmouseevent.sip.in b/python/gui/auto_generated/qgsmapmouseevent.sip.in
@@ -119,9 +119,11 @@ Alias to pos()
 :return: Mouse position in pixel coordinates
 %End
 
-    void snapToGrid( double precision );
+    void snapToGrid( double precision, const QgsCoordinateReferenceSystem &crs );
 %Docstring
 Snaps the mapPoint to a grid with the given ``precision``.
+The snapping will be done in the specified ``crs``. If this crs is
+different from the mapCanvas crs, it will add some overhead.
 
 .. versionadded:: 3.4
 %End
diff --git a/src/gui/qgsmapmouseevent.cpp b/src/gui/qgsmapmouseevent.cpp
@@ -71,17 +71,21 @@ void QgsMapMouseEvent::setMapPoint( const QgsPointXY &point )
   mPixelPoint = mapToPixelCoordinates( point );
 }
 
-void QgsMapMouseEvent::snapToGrid( double precision )
+void QgsMapMouseEvent::snapToGrid( double precision, const QgsCoordinateReferenceSystem &crs )
 {
   if ( precision <= 0 )
     return;
 
-  mMapPoint.setX( std::round( mMapPoint.x() / precision ) * precision );
-  mMapPoint.setY( std::round( mMapPoint.y() / precision ) * precision );
+  QgsCoordinateTransform ct( mMapCanvas->mapSettings().destinationCrs(), crs, mMapCanvas->mapSettings().transformContext() );
 
-  // mSnapMatch = QgsPointLocator::Match( mSnapMatch.type(), mSnapMatch.layer(), mSnapMatch.featureId(), mSnapMatch.distance(), mMapPoint, mSnapMatch.vertexIndex(), mSnapMatch.edgePoints() );
+  QgsPointXY pt = ct.transform( mMapPoint );
 
-  setMapPoint( mMapPoint );
+  pt.setX( std::round( mMapPoint.x() / precision ) * precision );
+  pt.setY( std::round( mMapPoint.y() / precision ) * precision );
+
+  pt = ct.transform( pt, QgsCoordinateTransform::ReverseTransform );
+
+  setMapPoint( pt );
 }
 
 QPoint QgsMapMouseEvent::mapToPixelCoordinates( const QgsPointXY &point )
diff --git a/src/gui/qgsmapmouseevent.h b/src/gui/qgsmapmouseevent.h
@@ -128,10 +128,12 @@ class GUI_EXPORT QgsMapMouseEvent : public QMouseEvent
 
     /**
      * Snaps the mapPoint to a grid with the given \a precision.
+     * The snapping will be done in the specified \a crs. If this crs is
+     * different from the mapCanvas crs, it will add some overhead.
      *
      * \since QGIS 3.4
      */
-    void snapToGrid( double precision );
+    void snapToGrid( double precision, const QgsCoordinateReferenceSystem &crs );
 
   private:
 
diff --git a/src/gui/qgsmaptooladvanceddigitizing.cpp b/src/gui/qgsmaptooladvanceddigitizing.cpp
@@ -39,8 +39,11 @@ void QgsMapToolAdvancedDigitizing::canvasPressEvent( QgsMapMouseEvent *e )
     e->snapPoint();
   }
 
-  if ( currentVectorLayer() )
-    e->snapToGrid( currentVectorLayer()->geometryOptions().geometryPrecision );
+  QgsVectorLayer *layer = currentVectorLayer();
+  if ( layer )
+  {
+    e->snapToGrid( layer->geometryOptions().geometryPrecision, layer->crs() );
+  }
 
   cadCanvasPressEvent( e );
 }
@@ -76,8 +79,11 @@ void QgsMapToolAdvancedDigitizing::canvasReleaseEvent( QgsMapMouseEvent *e )
     e->snapPoint();
   }
 
-  if ( currentVectorLayer() )
-    e->snapToGrid( currentVectorLayer()->geometryOptions().geometryPrecision );
+  QgsVectorLayer *layer = currentVectorLayer();
+  if ( layer )
+  {
+    e->snapToGrid( layer->geometryOptions().geometryPrecision, layer->crs() );
+  }
 
   cadCanvasReleaseEvent( e );
 }
@@ -98,8 +104,11 @@ void QgsMapToolAdvancedDigitizing::canvasMoveEvent( QgsMapMouseEvent *e )
     e->snapPoint();
   }
 
-  if ( currentVectorLayer() )
-    e->snapToGrid( currentVectorLayer()->geometryOptions().geometryPrecision );
+  QgsVectorLayer *layer = currentVectorLayer();
+  if ( layer )
+  {
+    e->snapToGrid( layer->geometryOptions().geometryPrecision, layer->crs() );
+  }
 
   cadCanvasMoveEvent( e );
 }

Original file line number	Diff line number	Diff line change
`@@ -39,8 +39,11 @@ void QgsMapToolAdvancedDigitizing::canvasPressEvent( QgsMapMouseEvent *e )`
`39`	`39`	`e->snapPoint();`
`40`	`40`	`}`
`41`	`41`
`42`		`- if ( currentVectorLayer() )`
`43`		`- e->snapToGrid( currentVectorLayer()->geometryOptions().geometryPrecision );`
	`42`	`+ QgsVectorLayer *layer = currentVectorLayer();`
	`43`	`+ if ( layer )`
	`44`	`+ {`
	`45`	`+ e->snapToGrid( layer->geometryOptions().geometryPrecision, layer->crs() );`
	`46`	`+ }`
`44`	`47`
`45`	`48`	`cadCanvasPressEvent( e );`
`46`	`49`	`}`
`@@ -76,8 +79,11 @@ void QgsMapToolAdvancedDigitizing::canvasReleaseEvent( QgsMapMouseEvent *e )`
`76`	`79`	`e->snapPoint();`
`77`	`80`	`}`
`78`	`81`
`79`		`- if ( currentVectorLayer() )`
`80`		`- e->snapToGrid( currentVectorLayer()->geometryOptions().geometryPrecision );`
	`82`	`+ QgsVectorLayer *layer = currentVectorLayer();`
	`83`	`+ if ( layer )`
	`84`	`+ {`
	`85`	`+ e->snapToGrid( layer->geometryOptions().geometryPrecision, layer->crs() );`
	`86`	`+ }`
`81`	`87`
`82`	`88`	`cadCanvasReleaseEvent( e );`
`83`	`89`	`}`
`@@ -98,8 +104,11 @@ void QgsMapToolAdvancedDigitizing::canvasMoveEvent( QgsMapMouseEvent *e )`
`98`	`104`	`e->snapPoint();`
`99`	`105`	`}`
`100`	`106`
`101`		`- if ( currentVectorLayer() )`
`102`		`- e->snapToGrid( currentVectorLayer()->geometryOptions().geometryPrecision );`
	`107`	`+ QgsVectorLayer *layer = currentVectorLayer();`
	`108`	`+ if ( layer )`
	`109`	`+ {`
	`110`	`+ e->snapToGrid( layer->geometryOptions().geometryPrecision, layer->crs() );`
	`111`	`+ }`
`103`	`112`
`104`	`113`	`cadCanvasMoveEvent( e );`
`105`	`114`	`}`