Fix snapping on invisible geometry

Author: lbartoletti

python/core/qgspointlocator.sip.in

@@ -71,6 +71,13 @@ Get extent of the area point locator covers - if null then it caches the whole l
 Configure extent - if not null, it will index only that area
 
 .. versionadded:: 2.14
+%End
+
+    void setRenderContext( const QgsRenderContext &context );
+%Docstring
+Configure render context  - if not null, it will use to index only visible feature
+
+.. versionadded:: 3.2
 %End
 
     enum Type
@@ -199,7 +206,6 @@ Override of edgesInRect that construct rectangle from a center point and toleran
 find out if the point is in any polygons
 %End
 
-
     int cachedGeometryCount() const;
 %Docstring
 Return how many geometries are cached in the index

python/core/qgssnappingutils.sip.in

@@ -35,7 +35,7 @@ which keeps the configuration in sync with map canvas (e.g. current view, active
 %End
   public:
 
-    QgsSnappingUtils( QObject *parent /TransferThis/ = 0 );
+    QgsSnappingUtils( QObject *parent /TransferThis/ = 0, bool enableSnappingForInvisibleFeature = true );
 %Docstring
 Constructor for QgsSnappingUtils
 %End
@@ -139,6 +139,15 @@ Get extra information about the instance
     QgsSnappingConfig config() const;
 %Docstring
 The snapping configuration controls the behavior of this object
+%End
+
+    void setEnableSnappingForInvisibleFeature( bool enable );
+%Docstring
+Set if invisible features must be snapped or not.
+
+:param enable: Enable or not this feature
+
+.. versionadded:: 3.2
 %End
 
   public slots:

python/gui/qgsmapcanvassnappingutils.sip.in

@@ -9,6 +9,7 @@
 
 
 
+
 class QgsMapCanvasSnappingUtils : QgsSnappingUtils
 {
 %Docstring

resources/qgis_global_settings.ini

@@ -20,6 +20,9 @@ digitizing\default_snap_type=1
 # 2 = Project units
 digitizing\default_snapping_tolerance_unit=1
 
+# Snap on invisble feature
+digitizing\snap_invisible_feature=false
+
 # Default XYZ tile servers to include
 connections-xyz\OpenStreetMap\authcfg=
 connections-xyz\OpenStreetMap\password=

src/app/qgsoptions.cpp

@@ -971,6 +971,7 @@ QgsOptions::QgsOptions( QWidget *parent, Qt::WindowFlags fl, const QList<QgsOpti
 
   mSnappingMarkerColorButton->setColor( mSettings->value( QStringLiteral( "/qgis/digitizing/snap_color" ), QColor( Qt::magenta ) ).value<QColor>() );
   mSnappingTooltipsCheckbox->setChecked( mSettings->value( QStringLiteral( "/qgis/digitizing/snap_tooltip" ), false ).toBool() );
+  mEnableSnappingOnInvisibleFeatureCheckbox->setChecked( mSettings->value( QStringLiteral( "/qgis/digitizing/snap_invisible_feature" ), false ).toBool() );
 
   //vertex marker
   mMarkersOnlyForSelectedCheckBox->setChecked( mSettings->value( QStringLiteral( "/qgis/digitizing/marker_only_for_selected" ), true ).toBool() );
@@ -1483,6 +1484,7 @@ void QgsOptions::saveOptions()
 
   mSettings->setValue( QStringLiteral( "/qgis/digitizing/snap_color" ), mSnappingMarkerColorButton->color() );
   mSettings->setValue( QStringLiteral( "/qgis/digitizing/snap_tooltip" ), mSnappingTooltipsCheckbox->isChecked() );
+  mSettings->setValue( QStringLiteral( "/qgis/digitizing/snap_invisible_feature" ), mEnableSnappingOnInvisibleFeatureCheckbox->isChecked() );
 
   mSettings->setValue( QStringLiteral( "/qgis/digitizing/marker_only_for_selected" ), mMarkersOnlyForSelectedCheckBox->isChecked() );
 

src/core/layertree/qgslayertreemodellegendnode.cpp

@@ -331,6 +331,7 @@ bool QgsSymbolLegendNode::setData( const QVariant &value, int role )
   vlayer->renderer()->checkLegendSymbolItem( mItem.ruleKey(), value == Qt::Checked );
 
   emit dataChanged();
+  emit vlayer->styleChanged();
 
   vlayer->triggerRepaint();
 

src/core/qgspointlocator.cpp

@@ -21,6 +21,7 @@
 #include "qgswkbptr.h"
 #include "qgis.h"
 #include "qgslogger.h"
+#include "qgsrenderer.h"
 
 #include <SpatialIndex.h>
 
@@ -636,6 +637,9 @@ QgsPointLocator::QgsPointLocator( QgsVectorLayer *layer, const QgsCoordinateRefe
   connect( mLayer, &QgsVectorLayer::featureDeleted, this, &QgsPointLocator::onFeatureDeleted );
   connect( mLayer, &QgsVectorLayer::geometryChanged, this, &QgsPointLocator::onGeometryChanged );
   connect( mLayer, &QgsVectorLayer::dataChanged, this, &QgsPointLocator::destroyIndex );
+  connect( mLayer, &QgsVectorLayer::rendererChanged, this, &QgsPointLocator::destroyIndex );
+  connect( mLayer, &QgsVectorLayer::styleChanged, this, &QgsPointLocator::destroyIndex );
+  connect( mLayer, &QgsVectorLayer::layerModified, this, &QgsPointLocator::destroyIndex );
 }
 
 
@@ -661,6 +665,12 @@ void QgsPointLocator::setExtent( const QgsRectangle *extent )
   destroyIndex();
 }
 
+void QgsPointLocator::setRenderContext( const QgsRenderContext &context )
+{
+  mContext = std::unique_ptr<QgsRenderContext>( new QgsRenderContext( context ) );
+
+  destroyIndex();
+}
 
 bool QgsPointLocator::init( int maxFeaturesToIndex )
 {
@@ -686,6 +696,7 @@ bool QgsPointLocator::rebuildIndex( int maxFeaturesToIndex )
 
   QgsFeatureRequest request;
   request.setSubsetOfAttributes( QgsAttributeList() );
+
   if ( mExtent )
   {
     QgsRectangle rect = *mExtent;
@@ -704,13 +715,40 @@ bool QgsPointLocator::rebuildIndex( int maxFeaturesToIndex )
     }
     request.setFilterRect( rect );
   }
+
+  bool filter = false;
+  std::unique_ptr< QgsFeatureRenderer > renderer( mLayer->renderer() ? mLayer->renderer()->clone() : nullptr );
+  QgsRenderContext *ctx = nullptr;
+  if ( mContext )
+  {
+    mContext->expressionContext() << QgsExpressionContextUtils::layerScope( mLayer );
+    ctx = mContext.get();
+    if ( renderer )
+    {
+      // setup scale for scale dependent visibility (rule based)
+      renderer->startRender( *ctx, mLayer->fields() );
+      filter = renderer->capabilities() & QgsFeatureRenderer::Filter;
+      request.setSubsetOfAttributes( renderer->usedAttributes( *ctx ), mLayer->fields() );
+    }
+  }
+
   QgsFeatureIterator fi = mLayer->getFeatures( request );
   int indexedCount = 0;
+
   while ( fi.nextFeature( f ) )
   {
     if ( !f.hasGeometry() )
       continue;
 
+    if ( ctx && renderer )
+    {
+      ctx->expressionContext().setFeature( f );
+      if ( filter && !renderer->willRenderFeature( f, *ctx ) )
+      {
+        continue;
+      }
+    }
+
     if ( mTransform.isValid() )
     {
       try
@@ -761,6 +799,12 @@ bool QgsPointLocator::rebuildIndex( int maxFeaturesToIndex )
   QgsPointLocator_Stream stream( dataList );
   mRTree = RTree::createAndBulkLoadNewRTree( RTree::BLM_STR, stream, *mStorage, fillFactor, indexCapacity,
            leafCapacity, dimension, variant, indexId );
+
+  if ( ctx && renderer )
+  {
+    renderer->stopRender( *ctx );
+    renderer.release();
+  }
   return true;
 }
 
@@ -832,6 +876,7 @@ void QgsPointLocator::onFeatureDeleted( QgsFeatureId fid )
     mRTree->deleteData( rect2region( mGeoms[fid]->boundingBox() ), fid );
     delete mGeoms.take( fid );
   }
+
 }
 
 void QgsPointLocator::onGeometryChanged( QgsFeatureId fid, const QgsGeometry &geom )

src/core/qgspointlocator.h

@@ -18,12 +18,15 @@
 
 class QgsPointXY;
 class QgsVectorLayer;
+class QgsFeatureRenderer;
+class QgsRenderContext;
 
 #include "qgis_core.h"
 #include "qgsfeature.h"
 #include "qgspointxy.h"
 #include "qgscoordinatereferencesystem.h"
 #include "qgscoordinatetransform.h"
+#include <memory>
 
 class QgsPointLocator_VisitorNearestVertex;
 class QgsPointLocator_VisitorNearestEdge;
@@ -92,6 +95,12 @@ class CORE_EXPORT QgsPointLocator : public QObject
      */
     void setExtent( const QgsRectangle *extent );
 
+    /**
+     * Configure render context  - if not null, it will use to index only visible feature
+     * \since QGIS 3.2
+     */
+    void setRenderContext( const QgsRenderContext &context );
+
     /**
      * The type of a snap result or the filter type for a snap request.
      */
@@ -251,8 +260,6 @@ class CORE_EXPORT QgsPointLocator : public QObject
     //! find out if the point is in any polygons
     MatchList pointInPolygon( const QgsPointXY &point );
 
-    //
-
     /**
      * Return how many geometries are cached in the index
      * \since QGIS 2.14
@@ -278,11 +285,15 @@ class CORE_EXPORT QgsPointLocator : public QObject
     //! flag whether the layer is currently empty (i.e. mRTree is null but it is not necessary to rebuild it)
     bool mIsEmptyLayer;
 
+    QgsFeatureIds mFeatureIds;
+
     //! R-tree containing spatial index
     QgsCoordinateTransform mTransform;
     QgsVectorLayer *mLayer = nullptr;
     QgsRectangle *mExtent = nullptr;
 
+    std::unique_ptr<QgsRenderContext> mContext;
+
     friend class QgsPointLocator_VisitorNearestVertex;
     friend class QgsPointLocator_VisitorNearestEdge;
     friend class QgsPointLocator_VisitorArea;

src/core/qgssnappingutils.cpp

@@ -19,10 +19,12 @@
 #include "qgsproject.h"
 #include "qgsvectorlayer.h"
 #include "qgslogger.h"
+#include "qgsrenderer.h"
 
-QgsSnappingUtils::QgsSnappingUtils( QObject *parent )
+QgsSnappingUtils::QgsSnappingUtils( QObject *parent, bool enableSnappingForInvisibleFeature )
   : QObject( parent )
   , mSnappingConfig( QgsProject::instance() )
+  , mEnableSnappingForInvisibleFeature( enableSnappingForInvisibleFeature )
 {
 }
 
@@ -92,7 +94,6 @@ bool QgsSnappingUtils::isIndexPrepared( QgsVectorLayer *vl, const QgsRectangle &
   return ( mStrategy == IndexHybrid || mStrategy == IndexExtent ) && loc->hasIndex() && ( !loc->extent() || loc->extent()->contains( aoi ) ); // the index - even if it exists - is not suitable
 }
 
-
 static QgsPointLocator::Match _findClosestSegmentIntersection( const QgsPointXY &pt, const QgsPointLocator::MatchList &segments )
 {
   if ( segments.isEmpty() )
@@ -156,9 +157,9 @@ static QgsPointLocator::Match _findClosestSegmentIntersection( const QgsPointXY
   return QgsPointLocator::Match( QgsPointLocator::Vertex, nullptr, 0, std::sqrt( minSqrDist ), minP );
 }
 
-
 static void _replaceIfBetter( QgsPointLocator::Match &bestMatch, const QgsPointLocator::Match &candidateMatch, double maxDistance )
 {
+
   // is candidate match relevant?
   if ( !candidateMatch.isValid() || candidateMatch.distance() > maxDistance )
     return;
@@ -174,7 +175,6 @@ static void _replaceIfBetter( QgsPointLocator::Match &bestMatch, const QgsPointL
   bestMatch = candidateMatch; // the other match is better!
 }
 
-
 static void _updateBestMatch( QgsPointLocator::Match &bestMatch, const QgsPointXY &pointMap, QgsPointLocator *loc, QgsPointLocator::Types type, double tolerance, QgsPointLocator::MatchFilter *filter )
 {
   if ( type & QgsPointLocator::Vertex )
@@ -329,7 +329,6 @@ QgsPointLocator::Match QgsSnappingUtils::snapToMap( const QgsPointXY &pointMap,
   return QgsPointLocator::Match();
 }
 
-
 void QgsSnappingUtils::prepareIndex( const QList<LayerAndAreaOfInterest> &layers )
 {
   if ( mIsIndexing )
@@ -341,6 +340,7 @@ void QgsSnappingUtils::prepareIndex( const QList<LayerAndAreaOfInterest> &layers
   Q_FOREACH ( const LayerAndAreaOfInterest &entry, layers )
   {
     QgsVectorLayer *vl = entry.first;
+
     if ( vl->geometryType() == QgsWkbTypes::NullGeometry || mStrategy == IndexNeverFull )
       continue;
 
@@ -359,7 +359,12 @@ void QgsSnappingUtils::prepareIndex( const QList<LayerAndAreaOfInterest> &layers
       QgsVectorLayer *vl = entry.first;
       QTime tt;
       tt.start();
+
       QgsPointLocator *loc = locatorForLayer( vl );
+
+      if ( !mEnableSnappingForInvisibleFeature )
+        loc->setRenderContext( QgsRenderContext::fromMapSettings( mMapSettings ) );
+
       if ( mStrategy == IndexExtent )
       {
         QgsRectangle rect( mMapSettings.extent() );
@@ -428,6 +433,11 @@ QgsSnappingConfig QgsSnappingUtils::config() const
   return mSnappingConfig;
 }
 
+void QgsSnappingUtils::setEnableSnappingForInvisibleFeature( bool enable )
+{
+  mEnableSnappingForInvisibleFeature = enable;
+}
+
 void QgsSnappingUtils::setConfig( const QgsSnappingConfig &config )
 {
   if ( mSnappingConfig == config )

src/core/qgssnappingutils.h

@@ -53,7 +53,7 @@ class CORE_EXPORT QgsSnappingUtils : public QObject
   public:
 
     //! Constructor for QgsSnappingUtils
-    QgsSnappingUtils( QObject *parent SIP_TRANSFERTHIS = nullptr );
+    QgsSnappingUtils( QObject *parent SIP_TRANSFERTHIS = nullptr, bool enableSnappingForInvisibleFeature = true );
     ~QgsSnappingUtils() override;
 
     // main actions
@@ -159,6 +159,15 @@ class CORE_EXPORT QgsSnappingUtils : public QObject
      */
     QgsSnappingConfig config() const;
 
+    /**
+     * Set if invisible features must be snapped or not.
+     *
+     * \param enable Enable or not this feature
+     *
+     * \since QGIS 3.2
+     */
+    void setEnableSnappingForInvisibleFeature( bool enable );
+
   public slots:
 
     /**
@@ -242,6 +251,10 @@ class CORE_EXPORT QgsSnappingUtils : public QObject
 
     //! internal flag that an indexing process is going on. Prevents starting two processes in parallel.
     bool mIsIndexing = false;
+
+    //! Disable or not the snapping on all features. By default is always true except for non visible features on map canvas.
+    bool mEnableSnappingForInvisibleFeature = true;
+
 };