void QgsPointDisplacementRenderer::createDisplacementGroups( QgsVectorLayer* vlayer, const QgsRectangle& viewExtent )
{
if ( !vlayer || ( vlayer->wkbType() != QGis::WKBPoint && vlayer->wkbType() != QGis::WKBPoint25D ) )
{
return;
}
mDisplacementGroups.clear();
mDisplacementIds.clear();
//use a spatial index to check if there is already a point at a position
QgsSpatialIndex spatialIndex;
//attributes
QgsAttributeList attList;
QList<QString> attributeStrings = usedAttributes();
QList<QString>::const_iterator attStringIt = attributeStrings.constBegin();
for ( ; attStringIt != attributeStrings.constEnd(); ++attStringIt )
{
attList.push_back( vlayer->fieldNameIndex( *attStringIt ) );
}
QgsFeature f;
QList<QgsFeatureId> intersectList;
//Because the new vector api does not allow querying features by id within a nextFeature loop, default constructed QgsFeature() is
//inserted first and the real features are created in a second loop
QgsFeatureIterator fit = vlayer->getFeatures( QgsFeatureRequest().setFilterRect( viewExtent ).setSubsetOfAttributes( attList ) );
while ( fit.nextFeature( f ) )
{
intersectList.clear();
//check, if there is already a point at that position
if ( f.geometry() )
{
intersectList = spatialIndex.intersects( searchRect( f.geometry()->asPoint() ) );
if ( intersectList.empty() )
{
spatialIndex.insertFeature( f );
}
else
{
//go through all the displacement group maps and search an entry where the id equals the result of the spatial search
QgsFeatureId existingEntry = intersectList.at( 0 );
bool found = false;
QList< QMap<QgsFeatureId, QgsFeature> >::iterator it = mDisplacementGroups.begin();
for ( ; it != mDisplacementGroups.end(); ++it )
{
if ( it->size() > 0 && it->contains( existingEntry ) )
{
found = true;
QgsFeature feature;
it->insert( f.id(), QgsFeature() );
mDisplacementIds.insert( f.id() );
break;
}
}
if ( !found )//insert the already existing feature and the new one into a map
{
QMap<QgsFeatureId, QgsFeature> newMap;
newMap.insert( existingEntry, QgsFeature() );
mDisplacementIds.insert( existingEntry );
newMap.insert( f.id(), QgsFeature() );
mDisplacementIds.insert( f.id() );
mDisplacementGroups.push_back( newMap );
}
}
}
}
//insert the real features into mDisplacementGroups
QList< QMap<QgsFeatureId, QgsFeature> >::iterator it = mDisplacementGroups.begin();
for ( ; it != mDisplacementGroups.end(); ++it )
{
QMap<QgsFeatureId, QgsFeature>::iterator mapIt = it->begin();
for ( ; mapIt != it->end(); ++mapIt )
{
QgsFeature fet;
vlayer->getFeatures( QgsFeatureRequest().setFilterFid( mapIt.key() ) ).nextFeature( fet );
mapIt.value() = fet;
}
}
}
void QgsPointDisplacementRenderer::createDisplacementGroups( QgsVectorLayer* vlayer, const QgsRectangle& viewExtent )
{
if ( !vlayer || ( vlayer->wkbType() != QGis::WKBPoint && vlayer->wkbType() != QGis::WKBPoint25D ) )
{
return;
}
mDisplacementGroups.clear();
mDisplacementIds.clear();
//use a spatial index to check if there is already a point at a position
QgsSpatialIndex spatialIndex;
//attributes
QgsAttributeList attList;
QList<QString> attributeStrings = usedAttributes();
QList<QString>::const_iterator attStringIt = attributeStrings.constBegin();
for ( ; attStringIt != attributeStrings.constEnd(); ++attStringIt )
{
attList.push_back( vlayer->fieldNameIndex( *attStringIt ) );
}
QgsFeature f;
QList<int> intersectList;
vlayer->select( attList, viewExtent, true, false );
while ( vlayer->nextFeature( f ) )
{
intersectList.clear();
//check, if there is already a point at that position
if ( f.geometry() )
{
intersectList = spatialIndex.intersects( searchRect( f.geometry()->asPoint() ) );
if ( intersectList.empty() )
{
spatialIndex.insertFeature( f );
}
else
{
//go through all the displacement group maps and search an entry where the id equals the result of the spatial search
int existingEntry = intersectList.at( 0 );
bool found = false;
QList<QMap<int, QgsFeature> >::iterator it = mDisplacementGroups.begin();
for ( ; it != mDisplacementGroups.end(); ++it )
{
if ( it->size() > 0 && it->contains( existingEntry ) )
{
found = true;
QgsFeature feature;
it->insert( f.id(), f );
mDisplacementIds.insert( f.id() );
break;
}
}
if ( !found )//insert the already existing feature and the new one into a map
{
QMap<int, QgsFeature> newMap;
QgsFeature existingFeature;
vlayer->featureAtId( existingEntry, existingFeature );
newMap.insert( existingEntry, existingFeature );
mDisplacementIds.insert( existingEntry );
newMap.insert( f.id(), f );
mDisplacementIds.insert( f.id() );
mDisplacementGroups.push_back( newMap );
}
}
}
}
//refresh the selection because the vector layer is going to step through all features now
vlayer->select( attList, viewExtent, true, false );
}
