[FEATURE][map overview] Support zooming in/out by scrolling mouse whe…

…el over map overview panel
qgis · Dec 10, 2020 · e1933c8 · e1933c8
1 parent d78665d
commit e1933c8
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Showing 5 changed files with 51 additions and 2 deletions.
diff --git a/python/gui/auto_generated/qgsmapcanvas.sip.in b/python/gui/auto_generated/qgsmapcanvas.sip.in
@@ -961,6 +961,16 @@ Set a list of resolutions (map units per pixel) to which to "snap to" when zoomi
 :param resolutions: A list of resolutions
 
 .. versionadded:: 3.12
+%End
+
+    double zoomInFactor() const;
+%Docstring
+Returns the zoom in factor.
+%End
+
+    double zoomOutFactor() const;
+%Docstring
+Returns the zoom in factor.
 %End
 
     const QList<double> &zoomResolutions() const;

diff --git a/python/gui/auto_generated/qgsmapoverviewcanvas.sip.in b/python/gui/auto_generated/qgsmapoverviewcanvas.sip.in
@@ -104,6 +104,12 @@ Overridden mouse press event
 
     virtual void mouseReleaseEvent( QMouseEvent *e );
 
+%Docstring
+Overridden mouse release event
+%End
+
+    virtual void wheelEvent( QWheelEvent *e );
+
 %Docstring
 Overridden mouse release event
 %End

diff --git a/src/gui/qgsmapcanvas.h b/src/gui/qgsmapcanvas.h
@@ -872,6 +872,16 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
      */
     void setZoomResolutions( const QList<double> &resolutions ) { mZoomResolutions = resolutions; }
 
+    /**
+     * Returns the zoom in factor.
+     */
+    double zoomInFactor() const;
+
+    /**
+     * Returns the zoom in factor.
+     */
+    double zoomOutFactor() const;
+
     /**
      * \returns List of resolutions to which to "snap to" when zooming the map
      * \see setZoomResolutions()
@@ -1329,8 +1339,6 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     bool panOperationInProgress();
 
     int nextZoomLevel( const QList<double> &resolutions, bool zoomIn = true ) const;
-    double zoomInFactor() const;
-    double zoomOutFactor() const;
 
     /**
      * Make sure to remove any rendered images of temporal-enabled layers from cache (does nothing if cache is not enabled)

diff --git a/src/gui/qgsmapoverviewcanvas.cpp b/src/gui/qgsmapoverviewcanvas.cpp
@@ -145,6 +145,28 @@ void QgsMapOverviewCanvas::mouseReleaseEvent( QMouseEvent *e )
 }
 
 
+void QgsMapOverviewCanvas::wheelEvent( QWheelEvent *e )
+{
+  double zoomFactor = e->angleDelta().y() > 0 ? 1. / mMapCanvas->zoomInFactor() : mMapCanvas->zoomOutFactor();
+
+  // "Normal" mouse have an angle delta of 120, precision mouses provide data faster, in smaller steps
+  zoomFactor = 1.0 + ( zoomFactor - 1.0 ) / 120.0 * std::fabs( e->angleDelta().y() );
+
+  if ( e->modifiers() & Qt::ControlModifier )
+  {
+    //holding ctrl while wheel zooming results in a finer zoom
+    zoomFactor = 1.0 + ( zoomFactor - 1.0 ) / 20.0;
+  }
+
+  double signedWheelFactor = e->angleDelta().y() > 0 ? 1 / zoomFactor : zoomFactor;
+
+  const QgsMapToPixel &cXf = mSettings.mapToPixel();
+  QgsPointXY center = cXf.toMapCoordinates( e->pos() );
+
+  updatePanningWidget( e->pos() );
+  mMapCanvas->zoomByFactor( signedWheelFactor, &center );
+}
+
 void QgsMapOverviewCanvas::mouseMoveEvent( QMouseEvent *e )
 {
   // move with panning widget if tracking cursor

diff --git a/src/gui/qgsmapoverviewcanvas.h b/src/gui/qgsmapoverviewcanvas.h
@@ -95,6 +95,9 @@ class GUI_EXPORT QgsMapOverviewCanvas : public QWidget
     //! Overridden mouse release event
     void mouseReleaseEvent( QMouseEvent *e ) override;
 
+    //! Overridden mouse release event
+    void wheelEvent( QWheelEvent *e ) override;
+
     //! called when panning to reflect mouse movement
     void updatePanningWidget( QPoint pos );