fix snapping indicator when advance digitizing tools is enabled

python/gui/auto_generated/qgsadvanceddigitizingdockwidget.sip.in

@@ -242,6 +242,10 @@ Constraint on the Y coordinate
     bool commonAngleConstraint() const;
 %Docstring
 Constraint on a common angle
+%End
+    QgsPointLocator::Match mapPointMatch() const;
+%Docstring
+SnapMatch for indicator
 %End
 
     void clearPoints();

src/gui/qgsadvanceddigitizingcanvasitem.cpp

@@ -28,6 +28,7 @@ QgsAdvancedDigitizingCanvasItem::QgsAdvancedDigitizingCanvasItem( QgsMapCanvas *
   , mSnapPen( QPen( QColor( 127, 0, 0, 150 ), 1 ) )
   , mSnapLinePen( QPen( QColor( 127, 0, 0, 150 ), 1, Qt::DashLine ) )
   , mCursorPen( QPen( QColor( 127, 127, 127, 255 ), 1 ) )
+  , mSnapIndicator( qgis::make_unique< QgsSnapIndicator>( canvas ) )
   , mAdvancedDigitizingDockWidget( cadDockWidget )
 {
 }
@@ -236,7 +237,16 @@ void QgsAdvancedDigitizingCanvasItem::paint( QPainter *painter )
                        curPointPix + QPointF( +5, +5 ) );
     painter->drawLine( curPointPix + QPointF( -5, +5 ),
                        curPointPix + QPointF( +5, -5 ) );
-
   }
 
+
+  QgsPointLocator::Match match = mAdvancedDigitizingDockWidget->mapPointMatch();
+  if ( match.isValid() )
+  {
+    mSnapIndicator->setMatch( match );
+    mSnapIndicator->setVisible( true );
+  }
+  else
+    mSnapIndicator->setVisible( false );
+
 }

src/gui/qgsadvanceddigitizingcanvasitem.h

@@ -20,6 +20,7 @@
 
 #include "qgsmapcanvasitem.h"
 #include "qgis_gui.h"
+#include "qgssnapindicator.h"
 
 class QgsAdvancedDigitizingDockWidget;
 
@@ -41,6 +42,8 @@ class GUI_EXPORT QgsAdvancedDigitizingCanvasItem : public QgsMapCanvasItem
     QPen mSnapPen;
     QPen mSnapLinePen;
     QPen mCursorPen;
+    //! Snapping indicators
+    std::unique_ptr<QgsSnapIndicator> mSnapIndicator;
 
   private:
     QgsAdvancedDigitizingDockWidget *mAdvancedDigitizingDockWidget = nullptr;

src/gui/qgsadvanceddigitizingdockwidget.cpp

@@ -557,6 +557,8 @@ bool QgsAdvancedDigitizingDockWidget::applyConstraints( QgsMapMouseEvent *e )
   // set the point coordinates in the map event
   e->setMapPoint( point );
 
+  mSnapMatch = context.snappingUtils->snapToMap( point );
+
   // update the point list
   updateCurrentPoint( point );
 

src/gui/qgsadvanceddigitizingdockwidget.h

@@ -26,6 +26,7 @@
 #include "qgsdockwidget.h"
 #include "qgsmessagebaritem.h"
 #include "qgspointxy.h"
+#include "qgspointlocator.h"
 
 
 class QgsAdvancedDigitizingCanvasItem;
@@ -255,6 +256,8 @@ class GUI_EXPORT QgsAdvancedDigitizingDockWidget : public QgsDockWidget, private
     const CadConstraint *constraintY() const { return mYConstraint.get(); }
     //! Constraint on a common angle
     bool commonAngleConstraint() const { return !qgsDoubleNear( mCommonAngleConstraint, 0.0 ); }
+    //! SnapMatch for indicator
+    QgsPointLocator::Match mapPointMatch() const { return mSnapMatch; }
 
     /**
      * Removes all points from the CAD point list
@@ -485,6 +488,9 @@ class GUI_EXPORT QgsAdvancedDigitizingDockWidget : public QgsDockWidget, private
     QAction *mEnableAction = nullptr;
     QMap< QAction *, double > mCommonAngleActions; // map the common angle actions with their angle values
 
+    // Snap indicator
+
+    QgsPointLocator::Match mSnapMatch;
   private:
 #ifdef SIP_RUN
     //! event filter for line edits in the dock UI (angle/distance/x/y line edits)

src/gui/qgssnapindicator.cpp

@@ -30,7 +30,6 @@ QgsSnapIndicator::QgsSnapIndicator( QgsMapCanvas *canvas )
 
 QgsSnapIndicator::~QgsSnapIndicator() = default;
 
-
 void QgsSnapIndicator::setMatch( const QgsPointLocator::Match &match )
 {
   mMatch = match;
@@ -65,6 +64,7 @@ void QgsSnapIndicator::setMatch( const QgsPointLocator::Match &match )
     {
       iconType = QgsVertexMarker::ICON_DOUBLE_TRIANGLE;
     }
+
     mSnappingMarker->setIconType( iconType );
 
     mSnappingMarker->setCenter( match.point() );
@@ -83,10 +83,14 @@ void QgsSnapIndicator::setMatch( const QgsPointLocator::Match &match )
 
 void QgsSnapIndicator::setVisible( bool visible )
 {
-  mSnappingMarker->setVisible( visible );
+  if ( mSnappingMarker )
+    mSnappingMarker->setVisible( visible );
 }
 
 bool QgsSnapIndicator::isVisible() const
 {
-  return mSnappingMarker->isVisible();
+  if ( mSnappingMarker )
+    return mSnappingMarker->isVisible();
+
+  return false;
 }