Add QgsAbstractFeatureIterator::updateRequestToSourceCrs method

The method superceeds filterRectToSourceCrs, deprecating it for shortage of functionality now that we support multiple spatial filters. This commit makes use of the new method from QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator so to not drop the WithinDistance spatial filter from the user Request. References #45352 (cherry picked from commit 3004fde)
qgis · Jan 31, 2022 · b46420b · b46420b
1 parent 6c08116
commit b46420b
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Showing 4 changed files with 63 additions and 14 deletions.
diff --git a/python/core/auto_generated/qgsfeatureiterator.sip.in b/python/core/auto_generated/qgsfeatureiterator.sip.in
@@ -138,6 +138,17 @@ Will throw a :py:class:`QgsCsException` if the rect cannot be transformed from t
 .. versionadded:: 3.0
 %End
 
+    void updateRequestToSourceCrs( QgsFeatureRequest &request, const QgsCoordinateTransform &transform ) const throw( QgsCsException );
+%Docstring
+Update a :py:class:`QgsFeatureRequest` so that spatial filters are
+transformed to the source's coordinate reference system.
+Iterators should call this method against the request used for filtering
+features to ensure that any :py:func:`QgsFeatureRequest.destinationCrs()` set on the request is respected.
+Will throw a :py:class:`QgsCsException` if the rect cannot be transformed from the destination CRS.
+
+.. versionadded:: 3.22
+%End
+
 
 
 

diff --git a/src/core/qgsfeatureiterator.cpp b/src/core/qgsfeatureiterator.cpp
@@ -17,6 +17,7 @@
 
 #include "qgssimplifymethod.h"
 #include "qgsexception.h"
+#include "qgslinestring.h"
 #include "qgsexpressionsorter.h"
 #include "qgsfeedback.h"
 #include "qgscoordinatetransform.h"
@@ -120,6 +121,37 @@ void QgsAbstractFeatureIterator::geometryToDestinationCrs( QgsFeature &feature,
   }
 }
 
+void QgsAbstractFeatureIterator::updateRequestToSourceCrs( QgsFeatureRequest &request, const QgsCoordinateTransform &transform ) const
+{
+  switch ( request.spatialFilterType() )
+  {
+    case Qgis::SpatialFilterType::NoFilter:
+      break;
+    case Qgis::SpatialFilterType::BoundingBox:
+    {
+      QgsRectangle newRect = transform.transformBoundingBox( request.filterRect(), Qgis::TransformDirection::Reverse );
+      request.setFilterRect( newRect );
+      break;
+    }
+    case Qgis::SpatialFilterType::DistanceWithin:
+    {
+      QgsGeometry geom = request.referenceGeometry();
+      QgsRectangle bbox = geom.boundingBox();
+      double x0 = bbox.xMaximum();
+      double y0 = bbox.yMaximum();
+      double dist = request.distanceWithin();
+      QgsPoint p0( x0, y0 );
+      QgsPoint p1( x0 + dist, y0 );
+      QgsLineString newDistLine( p0, p1 );
+      newDistLine.transform( transform, Qgis::TransformDirection::Reverse );
+      dist = newDistLine.length();
+      geom.transform( transform, Qgis::TransformDirection::Reverse );
+      request.setDistanceWithin( geom, dist );
+      break;
+    }
+  }
+}
+
 QgsRectangle QgsAbstractFeatureIterator::filterRectToSourceCrs( const QgsCoordinateTransform &transform ) const
 {
   if ( mRequest.filterRect().isNull() )

diff --git a/src/core/qgsfeatureiterator.h b/src/core/qgsfeatureiterator.h
@@ -149,6 +149,16 @@ class CORE_EXPORT QgsAbstractFeatureIterator
      */
     QgsRectangle filterRectToSourceCrs( const QgsCoordinateTransform &transform ) const SIP_THROW( QgsCsException );
 
+    /**
+     * Update a QgsFeatureRequest so that spatial filters are
+     * transformed to the source's coordinate reference system.
+     * Iterators should call this method against the request used for filtering
+     * features to ensure that any QgsFeatureRequest::destinationCrs() set on the request is respected.
+     * Will throw a QgsCsException if the rect cannot be transformed from the destination CRS.
+     * \since QGIS 3.22
+     */
+    void updateRequestToSourceCrs( QgsFeatureRequest &request, const QgsCoordinateTransform &transform ) const SIP_THROW( QgsCsException );
+
     //! A copy of the feature request.
     QgsFeatureRequest mRequest;
 

diff --git a/src/core/vector/qgsvectorlayerfeatureiterator.cpp b/src/core/vector/qgsvectorlayerfeatureiterator.cpp
@@ -128,17 +128,6 @@ QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayerFeat
   {
     mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs(), mRequest.transformContext() );
   }
-  try
-  {
-    mFilterRect = filterRectToSourceCrs( mTransform );
-  }
-  catch ( QgsCsException & )
-  {
-    // can't reproject mFilterRect
-    close();
-    return;
-  }
-
 
   // prepare spatial filter geometries for optimal speed
   switch ( mRequest.spatialFilterType() )
@@ -158,12 +147,19 @@ QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayerFeat
       break;
   }
 
-  if ( !mFilterRect.isNull() )
+  try
+  {
+    updateRequestToSourceCrs( mRequest, mTransform );
+    mFilterRect = mRequest.filterRect();
+  }
+  catch ( QgsCsException & )
   {
-    // update request to be the unprojected filter rect
-    mRequest.setFilterRect( mFilterRect );
+    // can't reproject request filters
+    close();
+    return;
   }
 
+
   // check whether the order by clause(s) can be delegated to the provider
   mDelegatedOrderByToProvider = !mSource->mHasEditBuffer;
   if ( !mRequest.orderBy().isEmpty() )