Added convenience method snappingUtils() to QgsMapCanvas

Map tools can use canvas.snappingUtils().snapToMap(pt) to do the snapping.

python/gui/qgisinterface.sip

@@ -32,13 +32,6 @@ class QgisInterface : QObject
 
     virtual QgsLayerTreeView* layerTreeView() = 0;
 
-    /**
-     * Get access to snapping utilities - for use in map tools
-     *
-     * @note added in 2.8
-     */
-    virtual QgsSnappingUtils* snappingUtils() = 0;
-
   public slots: // TODO: do these functions really need to be slots?
 
     /* Exposed functions */

python/gui/qgsmapcanvas.sip

@@ -309,6 +309,23 @@ class QgsMapCanvas : QGraphicsView
      * @note added in 2.3 */
     QgsPreviewEffect::PreviewMode previewMode() const;
 
+    /** Return snapping utility class that is associated with map canvas.
+     *  If no snapping utils instance has been associated previously, an internal will be created for convenience
+     *  (so map tools do not need to test for existence of the instance).
+     *
+     * Main canvas in QGIS returns an instance which is always up-to-date with the project's snapping configuration.
+     *  @note added in 2.8
+     */
+    QgsSnappingUtils* snappingUtils() const;
+    /** Assign an instance of snapping utils to the map canvas.
+     * The instance is not owned by the canvas, so it is possible to use one instance in multiple canvases.
+     *
+     * For main canvas in QGIS, do not associate a different instance from the existing one (it is updated from
+     * the project's snapping configuration).
+     * @note added in 2.8
+     */
+    void setSnappingUtils( QgsSnappingUtils* utils );
+
   public slots:
 
     /**Repaints the canvas map*/
@@ -437,6 +454,10 @@ class QgsMapCanvas : QGraphicsView
     //! @note added in 2.4
     void mapUnitsChanged();
 
+    //! Emitted when the current layer is changed
+    //! @note added in 2.8
+    void currentLayerChanged( QgsMapLayer* layer );
+
   protected:
     //! Overridden standard event to be gestures aware
     bool event( QEvent * e );

src/app/qgisapp.cpp

@@ -148,6 +148,7 @@
 #include "qgslayertreeviewdefaultactions.h"
 #include "qgslogger.h"
 #include "qgsmapcanvas.h"
+#include "qgsmapcanvassnappingutils.h"
 #include "qgsmaplayer.h"
 #include "qgsmaplayerregistry.h"
 #include "qgsmaplayerstyleguiutils.h"
@@ -192,7 +193,6 @@
 #include "qgsshortcutsmanager.h"
 #include "qgssinglebandgrayrenderer.h"
 #include "qgssnappingdialog.h"
-#include "qgssnappingutils.h"
 #include "qgssponsors.h"
 #include "qgssvgannotationitem.h"
 #include "qgstextannotationitem.h"
@@ -405,8 +405,6 @@ void QgisApp::activeLayerChanged( QgsMapLayer* layer )
 {
   if ( mMapCanvas )
     mMapCanvas->setCurrentLayer( layer );
-  if ( mSnappingUtils )
-    mSnappingUtils->setCurrentLayer( qobject_cast<QgsVectorLayer*>( layer ) );
 }
 
 /**
@@ -571,12 +569,11 @@ QgisApp::QgisApp( QSplashScreen *splash, bool restorePlugins, QWidget * parent,
   mAdvancedDigitizingDockWidget = new QgsAdvancedDigitizingDockWidget( mMapCanvas, this );
   mAdvancedDigitizingDockWidget->setObjectName( "AdvancedDigitizingTools" );
 
-  mSnappingUtils = new QgsSnappingUtils( this );
+  mSnappingUtils = new QgsMapCanvasSnappingUtils( mMapCanvas, this );
+  mMapCanvas->setSnappingUtils( mSnappingUtils );
   connect( QgsProject::instance(), SIGNAL( snapSettingsChanged() ), mSnappingUtils, SLOT( readConfigFromProject() ) );
   connect( this, SIGNAL( newProject() ), mSnappingUtils, SLOT( readConfigFromProject() ) );
   connect( this, SIGNAL( projectRead() ), mSnappingUtils, SLOT( readConfigFromProject() ) );
-  connect( mMapCanvas, SIGNAL( extentsChanged() ), this, SLOT( updateSnappingUtilsMapSettings() ) );
-  connect( mMapCanvas, SIGNAL( destinationCrsChanged() ), this, SLOT( updateSnappingUtilsMapSettings() ) );
 
   createActions();
   createActionGroups();
@@ -4369,11 +4366,6 @@ void QgisApp::updateFilterLegendByMap()
   layerTreeView()->layerTreeModel()->setLegendFilterByMap( &mMapCanvas->mapSettings() );
 }
 
-void QgisApp::updateSnappingUtilsMapSettings()
-{
-  mSnappingUtils->setMapSettings( mMapCanvas->mapSettings() );
-}
-
 void QgisApp::saveMapAsImage()
 {
   QPair< QString, QString> myFileNameAndFilter = QgisGui::getSaveAsImageName( this, tr( "Choose a file name to save the map image as" ) );

src/app/qgisapp.h

@@ -1214,11 +1214,6 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
     void updateFilterLegendByMap();
     void setFilterLegendByMapEnabled( bool enabled );
 
-  public:
-    QgsSnappingUtils* snappingUtils() { return mSnappingUtils; }
-  private slots:
-    void updateSnappingUtilsMapSettings();
-
     /** Make the user feel dizzy */
     void dizzy();
 

src/app/qgisappinterface.cpp

@@ -88,11 +88,6 @@ QgsLayerTreeView*QgisAppInterface::layerTreeView()
   return qgis->layerTreeView();
 }
 
-QgsSnappingUtils* QgisAppInterface::snappingUtils()
-{
-  return qgis->snappingUtils();
-}
-
 void QgisAppInterface::zoomFull()
 {
   qgis->zoomFull();

src/app/qgisappinterface.h

@@ -51,8 +51,6 @@ class APP_EXPORT QgisAppInterface : public QgisInterface
 
     QgsLayerTreeView* layerTreeView() override;
 
-    QgsSnappingUtils* snappingUtils();
-
     /* Exposed functions */
 
     //! Zoom map to full extent

src/app/qgsmapmouseevent.cpp

@@ -54,7 +54,7 @@ void QgsMapMouseEvent::setPoint( const QgsPoint& point )
 
 bool QgsMapMouseEvent::snapPoint()
 {
-  mSnapMatch = QgisApp::instance()->snappingUtils()->snapToMap( mMapPoint );
+  mSnapMatch = mMapTool->canvas()->snappingUtils()->snapToMap( mMapPoint );
   mMapPoint = mSnapMatch.isValid() ? mSnapMatch.point() : mOriginalPoint;
   return mSnapMatch.isValid();
 }

src/app/qgsmaptoolmeasureangle.cpp

@@ -21,6 +21,7 @@
 #include "qgsmaptopixel.h"
 #include "qgsproject.h"
 #include "qgsrubberband.h"
+#include "qgssnappingutils.h"
 #include <QMouseEvent>
 #include <QSettings>
 #include <cmath>
@@ -31,7 +32,6 @@ QgsMapToolMeasureAngle::QgsMapToolMeasureAngle( QgsMapCanvas* canvas )
     , mResultDisplay( 0 )
 {
   mToolName = tr( "Measure angle" );
-  mSnapper.setMapCanvas( canvas );
 
   connect( canvas, SIGNAL( destinationCrsChanged() ),
            this, SLOT( updateSettings() ) );
@@ -143,15 +143,8 @@ void QgsMapToolMeasureAngle::createRubberBand()
 
 QgsPoint QgsMapToolMeasureAngle::snapPoint( const QPoint& p )
 {
-  QList<QgsSnappingResult> snappingResults;
-  if ( mSnapper.snapToBackgroundLayers( p, snappingResults ) != 0 || snappingResults.size() < 1 )
-  {
-    return mCanvas->getCoordinateTransform()->toMapCoordinates( p );
-  }
-  else
-  {
-    return snappingResults.constBegin()->snappedVertex;
-  }
+  QgsPointLocator::Match m = mCanvas->snappingUtils()->snapToMap( p );
+  return m.isValid() ? m.point() : mCanvas->getCoordinateTransform()->toMapCoordinates( p );
 }
 
 void QgsMapToolMeasureAngle::updateSettings()

src/app/qgsmaptoolmeasureangle.h

@@ -17,7 +17,6 @@
 #define QGSMAPTOOLMEASUREANGLE_H
 
 #include "qgsmaptool.h"
-#include "qgsmapcanvassnapper.h"
 #include "qgspoint.h"
 #include "qgsdistancearea.h"
 
@@ -49,7 +48,6 @@ class APP_EXPORT QgsMapToolMeasureAngle: public QgsMapTool
     QList<QgsPoint> mAnglePoints;
     QgsRubberBand* mRubberBand;
     QgsDisplayAngle* mResultDisplay;
-    QgsMapCanvasSnapper mSnapper;
 
     /**Creates a new rubber band and deletes the old one*/
     void createRubberBand();

src/app/qgsmeasuretool.cpp

@@ -20,6 +20,7 @@
 #include "qgsmaptopixel.h"
 #include "qgsrubberband.h"
 #include "qgsvectorlayer.h"
+#include "qgssnappingutils.h"
 #include "qgstolerance.h"
 
 #include "qgsmeasuredialog.h"
@@ -47,7 +48,6 @@ QgsMeasureTool::QgsMeasureTool( QgsMapCanvas* canvas, bool measureArea )
 
   mDialog = new QgsMeasureDialog( this, Qt::WindowStaysOnTopHint );
   mDialog->restorePosition();
-  mSnapper.setMapCanvas( canvas );
 
   connect( canvas, SIGNAL( destinationCrsChanged() ),
            this, SLOT( updateSettings() ) );
@@ -238,15 +238,9 @@ void QgsMeasureTool::addPoint( QgsPoint &point )
   }
 }
 
+
 QgsPoint QgsMeasureTool::snapPoint( const QPoint& p )
 {
-  QList<QgsSnappingResult> snappingResults;
-  if ( mSnapper.snapToBackgroundLayers( p, snappingResults ) != 0 || snappingResults.size() < 1 )
-  {
-    return mCanvas->getCoordinateTransform()->toMapCoordinates( p );
-  }
-  else
-  {
-    return snappingResults.constBegin()->snappedVertex;
-  }
+  QgsPointLocator::Match m = mCanvas->snappingUtils()->snapToMap( p );
+  return m.isValid() ? m.point() : mCanvas->getCoordinateTransform()->toMapCoordinates( p );
 }

src/app/qgsmeasuretool.h

@@ -97,8 +97,6 @@ class APP_EXPORT QgsMeasureTool : public QgsMapTool
     // project projection
     bool mWrongProjectProjection;
 
-    QgsMapCanvasSnapper mSnapper;
-
     //! Returns the snapped (map) coordinate
     //@param p (pixel) coordinate
     QgsPoint snapPoint( const QPoint& p );

src/gui/CMakeLists.txt

@@ -177,6 +177,7 @@ qgsmapcanvas.cpp
 qgsmapcanvasitem.cpp
 qgsmapcanvasmap.cpp
 qgsmapcanvassnapper.cpp
+qgsmapcanvassnappingutils.cpp
 qgsmaplayeractionregistry.cpp
 qgsmaplayercombobox.cpp
 qgsmaplayermodel.cpp
@@ -284,6 +285,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsludialog.h
   qgsmanageconnectionsdialog.h
   qgsmapcanvas.h
+  qgsmapcanvassnappingutils.h
   qgsmaplayeractionregistry.h
   qgsmaplayercombobox.h
   qgsmaplayermodel.h
@@ -442,6 +444,7 @@ SET(QGIS_GUI_HDRS
   qgsmapcanvasitem.h
   qgsmapcanvasmap.h
   qgsmapcanvassnapper.h
+  qgsmapcanvassnappingutils.h
   qgsmaptip.h
   qgsmaptoolpan.h
   qgsmaptoolzoom.h

src/gui/qgisinterface.h

@@ -78,13 +78,6 @@ class GUI_EXPORT QgisInterface : public QObject
 
     virtual QgsLayerTreeView* layerTreeView() = 0;
 
-    /**
-     * Get access to snapping utilities - for use in map tools
-     *
-     * @note added in 2.8
-     */
-    virtual QgsSnappingUtils* snappingUtils() = 0;
-
   public slots: // TODO: do these functions really need to be slots?
 
     /* Exposed functions */

src/gui/qgsmapcanvas.cpp

@@ -44,6 +44,7 @@ email                : sherman at mrcc.com
 #include "qgslogger.h"
 #include "qgsmapcanvas.h"
 #include "qgsmapcanvasmap.h"
+#include "qgsmapcanvassnappingutils.h"
 #include "qgsmaplayer.h"
 #include "qgsmaplayerregistry.h"
 #include "qgsmaptoolpan.h"
@@ -190,6 +191,7 @@ QgsMapCanvas::QgsMapCanvas( QWidget * parent, const char *name )
     , mDrawRenderingStats( false )
     , mCache( 0 )
     , mPreviewEffect( 0 )
+    , mSnappingUtils( 0 )
 {
   setObjectName( name );
   mScene = new QGraphicsScene();
@@ -340,6 +342,7 @@ QgsMapLayer* QgsMapCanvas::layer( int index )
 void QgsMapCanvas::setCurrentLayer( QgsMapLayer* layer )
 {
   mCurrentLayer = layer;
+  emit currentLayerChanged( layer );
 }
 
 double QgsMapCanvas::scale()
@@ -1743,6 +1746,22 @@ QgsPreviewEffect::PreviewMode QgsMapCanvas::previewMode() const
   return mPreviewEffect->mode();
 }
 
+QgsSnappingUtils* QgsMapCanvas::snappingUtils() const
+{
+  if ( !mSnappingUtils )
+  {
+    // associate a dummy instance, but better than null pointer
+    QgsMapCanvas* c = const_cast<QgsMapCanvas*>( this );
+    c->mSnappingUtils = new QgsMapCanvasSnappingUtils( c, c );
+  }
+  return mSnappingUtils;
+}
+
+void QgsMapCanvas::setSnappingUtils( QgsSnappingUtils* utils )
+{
+  mSnappingUtils = utils;
+}
+
 void QgsMapCanvas::readProject( const QDomDocument & doc )
 {
   QDomNodeList nodes = doc.elementsByTagName( "mapcanvas" );

src/gui/qgsmapcanvas.h

@@ -65,6 +65,7 @@ class QgsMapSettings;
 class QgsMapCanvasMap;
 class QgsMapOverviewCanvas;
 class QgsMapTool;
+class QgsSnappingUtils;
 
 /** \ingroup gui
   * A class that stores visibility and presence in overview flags together
@@ -378,6 +379,23 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
      * @note added in 2.3 */
     QgsPreviewEffect::PreviewMode previewMode() const;
 
+    /** Return snapping utility class that is associated with map canvas.
+     *  If no snapping utils instance has been associated previously, an internal will be created for convenience
+     *  (so map tools do not need to test for existence of the instance).
+     *
+     * Main canvas in QGIS returns an instance which is always up-to-date with the project's snapping configuration.
+     *  @note added in 2.8
+     */
+    QgsSnappingUtils* snappingUtils() const;
+    /** Assign an instance of snapping utils to the map canvas.
+     * The instance is not owned by the canvas, so it is possible to use one instance in multiple canvases.
+     *
+     * For main canvas in QGIS, do not associate a different instance from the existing one (it is updated from
+     * the project's snapping configuration).
+     * @note added in 2.8
+     */
+    void setSnappingUtils( QgsSnappingUtils* utils );
+
   public slots:
 
     /**Repaints the canvas map*/
@@ -517,6 +535,10 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     //! @note added in 2.4
     void mapUnitsChanged();
 
+    //! Emitted when the current layer is changed
+    //! @note added in 2.8
+    void currentLayerChanged( QgsMapLayer* layer );
+
   protected:
 #ifdef HAVE_TOUCH
     //! Overridden standard event to be gestures aware
@@ -652,6 +674,9 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     QgsPreviewEffect* mPreviewEffect;
 
     QgsRectangle imageRect( const QImage& img );
+
+    QgsSnappingUtils* mSnappingUtils;
+
 }; // class QgsMapCanvas
 
 

src/gui/qgsmapcanvassnappingutils.cpp

@@ -0,0 +1,25 @@
+#include "qgsmapcanvassnappingutils.h"
+
+#include "qgsmapcanvas.h"
+#include "qgsvectorlayer.h"
+
+QgsMapCanvasSnappingUtils::QgsMapCanvasSnappingUtils( QgsMapCanvas* canvas, QObject* parent )
+  : QgsSnappingUtils( parent )
+  , mCanvas( canvas )
+{
+  connect( canvas, SIGNAL( extentsChanged() ), this, SLOT( canvasMapSettingsChanged() ) );
+  connect( canvas, SIGNAL( destinationCrsChanged() ), this, SLOT( canvasMapSettingsChanged() ) );
+  connect( canvas, SIGNAL( currentLayerChanged( QgsMapLayer* ) ), this, SLOT( canvasCurrentLayerChanged() ) );
+  canvasMapSettingsChanged();
+  canvasCurrentLayerChanged();
+}
+
+void QgsMapCanvasSnappingUtils::canvasMapSettingsChanged()
+{
+  setMapSettings( mCanvas->mapSettings() );
+}
+
+void QgsMapCanvasSnappingUtils::canvasCurrentLayerChanged()
+{
+  setCurrentLayer( qobject_cast<QgsVectorLayer*>( mCanvas->currentLayer() ) );
+}

src/gui/qgsmapcanvassnappingutils.h

@@ -0,0 +1,27 @@
+#ifndef QGSMAPCANVASSNAPPINGUTILS_H
+#define QGSMAPCANVASSNAPPINGUTILS_H
+
+#include "qgssnappingutils.h"
+
+class QgsMapCanvas;
+
+/** Snapping utils instance that is connected to a canvas and updates the configuration
+ *  (map settings + current layer) whenever that is changed in the canvas.
+ *  @note added in 2.8
+ */
+class GUI_EXPORT QgsMapCanvasSnappingUtils : public QgsSnappingUtils
+{
+  Q_OBJECT
+public:
+  QgsMapCanvasSnappingUtils( QgsMapCanvas* canvas, QObject* parent = 0 );
+
+private slots:
+  void canvasMapSettingsChanged();
+  void canvasCurrentLayerChanged();
+
+private:
+  QgsMapCanvas* mCanvas;
+};
+
+
+#endif // QGSMAPCANVASSNAPPINGUTILS_H