QgsGeometry* QgsMapToolOffsetCurve::createOriginGeometry( QgsVectorLayer* vl, const QgsPointLocator::Match& match, QgsFeature& snappedFeature )
{
if ( !vl )
{
return 0;
}
mMultiPartGeometry = false;
//assign feature part by vertex number (snap to vertex) or by before vertex number (snap to segment)
int partVertexNr = match.vertexIndex();
if ( vl == currentVectorLayer() && !mForceCopy )
{
//don't consider selected geometries, only the snap result
return convertToSingleLine( snappedFeature.geometryAndOwnership(), partVertexNr, mMultiPartGeometry );
}
else //snapped to a background layer
{
//if source layer is polygon / multipolygon, create a linestring from the snapped ring
if ( vl->geometryType() == QGis::Polygon )
{
//make linestring from polygon ring and return this geometry
return linestringFromPolygon( snappedFeature.geometry(), partVertexNr );
}
//for background layers, try to merge selected entries together if snapped feature is contained in selection
const QgsFeatureIds& selection = vl->selectedFeaturesIds();
if ( selection.size() < 1 || !selection.contains( match.featureId() ) )
{
return convertToSingleLine( snappedFeature.geometryAndOwnership(), partVertexNr, mMultiPartGeometry );
}
else
{
//merge together if several features
QgsFeatureList selectedFeatures = vl->selectedFeatures();
QgsFeatureList::iterator selIt = selectedFeatures.begin();
QgsGeometry* geom = selIt->geometryAndOwnership();
++selIt;
for ( ; selIt != selectedFeatures.end(); ++selIt )
{
QgsGeometry* combined = geom->combine( selIt->geometry() );
delete geom;
geom = combined;
}
//if multitype, return only the snapped to geometry
if ( geom->isMultipart() )
{
delete geom;
return convertToSingleLine( snappedFeature.geometryAndOwnership(), match.vertexIndex(), mMultiPartGeometry );
}
return geom;
}
}
}
void QgsGeometryAnalyzer::bufferFeature( QgsFeature& f, int nProcessedFeatures, QgsVectorFileWriter* vfw, bool dissolve,
QgsGeometry& dissolveGeometry, double bufferDistance, int bufferDistanceField )
{
if ( !f.hasGeometry() )
{
return;
}
double currentBufferDistance;
QgsGeometry featureGeometry = f.geometry();
QgsGeometry bufferGeometry;
//create buffer
if ( bufferDistanceField == -1 )
{
currentBufferDistance = bufferDistance;
}
else
{
currentBufferDistance = f.attribute( bufferDistanceField ).toDouble();
}
bufferGeometry = featureGeometry.buffer( currentBufferDistance, 5 );
if ( dissolve )
{
if ( nProcessedFeatures == 0 )
{
dissolveGeometry = bufferGeometry;
}
else
{
dissolveGeometry = dissolveGeometry.combine( bufferGeometry );
}
}
else //dissolve
{
QgsFeature newFeature;
newFeature.setGeometry( bufferGeometry );
newFeature.setAttributes( f.attributes() );
//add it to vector file writer
if ( vfw )
{
vfw->addFeature( newFeature );
}
}
}
QgsGeometry QgsGeometryAnalyzer::dissolveFeature( const QgsFeature& f, const QgsGeometry& dissolveInto )
{
if ( !f.hasGeometry() )
{
return dissolveInto;
}
QgsGeometry featureGeometry = f.geometry();
if ( dissolveInto.isEmpty() )
{
return featureGeometry;
}
else
{
return dissolveInto.combine( featureGeometry );
}
}
void QgsGeometryAnalyzer::convexFeature( QgsFeature& f, int nProcessedFeatures, QgsGeometry& dissolveGeometry )
{
if ( !f.hasGeometry() )
{
return;
}
QgsGeometry featureGeometry = f.geometry();
QgsGeometry convexGeometry = featureGeometry.convexHull();
if ( nProcessedFeatures == 0 )
{
dissolveGeometry = convexGeometry;
}
else
{
dissolveGeometry = dissolveGeometry.combine( convexGeometry );
}
}