snapToCurrentLayer correctly handles Area type

qgis · Feb 19, 2018 · 9e2e99f · 9e2e99f
1 parent 965a4e8
commit 9e2e99f
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Showing 4 changed files with 56 additions and 1 deletion.
diff --git a/python/core/qgspointlocator.sip.in b/python/core/qgspointlocator.sip.in
@@ -171,6 +171,16 @@ Optional filter may discard unwanted matches.
 %Docstring
 Find nearest edge to the specified point - up to distance specified by tolerance
 Optional filter may discard unwanted matches.
+%End
+
+    Match nearestArea( const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter = 0 );
+%Docstring
+Find nearest area to the specified point - up to distance specified by tolerance
+Optional filter may discard unwanted matches.
+This will first perform a pointInPolygon and return first result.
+If no match is found and tolerance is not 0, it will return nearestEdge.
+
+.. versionadded:: 3.0
 %End
 
     MatchList edgesInRect( const QgsRectangle &rect, QgsPointLocator::MatchFilter *filter = 0 );

diff --git a/src/core/qgspointlocator.cpp b/src/core/qgspointlocator.cpp
@@ -181,7 +181,6 @@ class QgsPointLocator_VisitorNearestEdge : public IVisitor
 
 ////////////////////////////////////////////////////////////////////////////
 
-
 /**
  * \ingroup core
  * Helper class used when traversing the index with areas - builds a list of matches.
@@ -883,6 +882,36 @@ QgsPointLocator::Match QgsPointLocator::nearestEdge( const QgsPointXY &point, do
   return m;
 }
 
+QgsPointLocator::Match QgsPointLocator::nearestArea( const QgsPointXY &point, double tolerance, MatchFilter *filter )
+{
+  if ( !mRTree )
+  {
+    init();
+    if ( !mRTree ) // still invalid?
+      return Match();
+  }
+
+  MatchList mlist = pointInPolygon( point );
+  if ( mlist.count() && mlist.at( 0 ).isValid() )
+  {
+    return mlist.at( 0 );
+  }
+
+  if ( tolerance == 0 )
+  {
+    return Match();
+  }
+
+  // discard point and line layers to keep only polygons
+  QgsWkbTypes::GeometryType geomType = mLayer->geometryType();
+  if ( geomType == QgsWkbTypes::PointGeometry || geomType == QgsWkbTypes::LineGeometry )
+    return Match();
+
+  // use edges for adding tolerance
+  return nearestEdge( point, tolerance, filter );
+}
+
+
 QgsPointLocator::MatchList QgsPointLocator::edgesInRect( const QgsRectangle &rect, QgsPointLocator::MatchFilter *filter )
 {
   if ( !mRTree )

diff --git a/src/core/qgspointlocator.h b/src/core/qgspointlocator.h
@@ -228,6 +228,15 @@ class CORE_EXPORT QgsPointLocator : public QObject
      */
     Match nearestEdge( const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter = nullptr );
 
+    /**
+     * Find nearest area to the specified point - up to distance specified by tolerance
+     * Optional filter may discard unwanted matches.
+     * This will first perform a pointInPolygon and return first result.
+     * If no match is found and tolerance is not 0, it will return nearestEdge.
+     * \since QGIS 3.0
+     */
+    Match nearestArea( const QgsPointXY &point, double tolerance, QgsPointLocator::MatchFilter *filter = nullptr );
+
     /**
      * Find edges within a specified recangle
      * Optional filter may discard unwanted matches.

diff --git a/src/core/qgssnappingutils.cpp b/src/core/qgssnappingutils.cpp
@@ -185,6 +185,13 @@ static void _updateBestMatch( QgsPointLocator::Match &bestMatch, const QgsPointX
   {
     _replaceIfBetter( bestMatch, loc->nearestEdge( pointMap, tolerance, filter ), tolerance );
   }
+  if ( bestMatch.type() != QgsPointLocator::Vertex && bestMatch.type() != QgsPointLocator::Edge && ( type & QgsPointLocator::Area ) )
+  {
+    // if edges were detected, set tolerance to 0 to only do pointInPolygon (and avoid redo nearestEdge)
+    if ( type & QgsPointLocator::Edge )
+      tolerance = 0;
+    _replaceIfBetter( bestMatch, loc->nearestArea( pointMap, tolerance, filter ), tolerance );
+  }
 }