QVariantMap QgsExtractByExtentAlgorithm::processAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
{
std::unique_ptr< QgsFeatureSource > featureSource( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
if ( !featureSource )
return QVariantMap();
QgsRectangle extent = parameterAsExtent( parameters, QStringLiteral( "EXTENT" ), context, featureSource->sourceCrs() );
bool clip = parameterAsBool( parameters, QStringLiteral( "CLIP" ), context );
// if clipping, we force multi output
QgsWkbTypes::Type outType = clip ? QgsWkbTypes::multiType( featureSource->wkbType() ) : featureSource->wkbType();
QString dest;
std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, featureSource->fields(), outType, featureSource->sourceCrs() ) );
if ( !sink )
return QVariantMap();
QgsGeometry clipGeom = parameterAsExtentGeometry( parameters, QStringLiteral( "EXTENT" ), context, featureSource->sourceCrs() );
double step = featureSource->featureCount() > 0 ? 100.0 / featureSource->featureCount() : 1;
QgsFeatureIterator inputIt = featureSource->getFeatures( QgsFeatureRequest().setFilterRect( extent ).setFlags( QgsFeatureRequest::ExactIntersect ) );
QgsFeature f;
int i = -1;
while ( inputIt.nextFeature( f ) )
{
i++;
if ( feedback->isCanceled() )
{
break;
}
if ( clip )
{
QgsGeometry g = f.geometry().intersection( clipGeom );
g.convertToMultiType();
f.setGeometry( g );
}
sink->addFeature( f, QgsFeatureSink::FastInsert );
feedback->setProgress( i * step );
}
QVariantMap outputs;
outputs.insert( QStringLiteral( "OUTPUT" ), dest );
return outputs;
}
QVariantMap QgsClipAlgorithm::processAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
{
std::unique_ptr< QgsFeatureSource > featureSource( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
if ( !featureSource )
throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
std::unique_ptr< QgsFeatureSource > maskSource( parameterAsSource( parameters, QStringLiteral( "OVERLAY" ), context ) );
if ( !maskSource )
throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "OVERLAY" ) ) );
QString dest;
QgsWkbTypes::GeometryType sinkType = QgsWkbTypes::geometryType( featureSource->wkbType() );
std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, featureSource->fields(), QgsWkbTypes::multiType( featureSource->wkbType() ), featureSource->sourceCrs() ) );
if ( !sink )
throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
// first build up a list of clip geometries
QVector< QgsGeometry > clipGeoms;
QgsFeatureIterator it = maskSource->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( QList< int >() ).setDestinationCrs( featureSource->sourceCrs(), context.transformContext() ) );
QgsFeature f;
while ( it.nextFeature( f ) )
{
if ( f.hasGeometry() )
clipGeoms << f.geometry();
}
QVariantMap outputs;
outputs.insert( QStringLiteral( "OUTPUT" ), dest );
if ( clipGeoms.isEmpty() )
return outputs;
// are we clipping against a single feature? if so, we can show finer progress reports
bool singleClipFeature = false;
QgsGeometry combinedClipGeom;
if ( clipGeoms.length() > 1 )
{
combinedClipGeom = QgsGeometry::unaryUnion( clipGeoms );
if ( combinedClipGeom.isEmpty() )
{
throw QgsProcessingException( QObject::tr( "Could not create the combined clip geometry: %1" ).arg( combinedClipGeom.lastError() ) );
}
singleClipFeature = false;
}
else
{
combinedClipGeom = clipGeoms.at( 0 );
singleClipFeature = true;
}
// use prepared geometries for faster intersection tests
std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( combinedClipGeom.constGet() ) );
engine->prepareGeometry();
QgsFeatureIds testedFeatureIds;
int i = -1;
Q_FOREACH ( const QgsGeometry &clipGeom, clipGeoms )
{
i++;
if ( feedback->isCanceled() )
{
break;
}
QgsFeatureIterator inputIt = featureSource->getFeatures( QgsFeatureRequest().setFilterRect( clipGeom.boundingBox() ) );
QgsFeatureList inputFeatures;
QgsFeature f;
while ( inputIt.nextFeature( f ) )
inputFeatures << f;
if ( inputFeatures.isEmpty() )
continue;
double step = 0;
if ( singleClipFeature )
step = 100.0 / inputFeatures.length();
int current = 0;
Q_FOREACH ( const QgsFeature &inputFeature, inputFeatures )
{
if ( feedback->isCanceled() )
{
break;
}
if ( !inputFeature.hasGeometry() )
continue;
if ( testedFeatureIds.contains( inputFeature.id() ) )
{
// don't retest a feature we have already checked
continue;
}
testedFeatureIds.insert( inputFeature.id() );
if ( !engine->intersects( inputFeature.geometry().constGet() ) )
continue;
QgsGeometry newGeometry;
if ( !engine->contains( inputFeature.geometry().constGet() ) )
{
QgsGeometry currentGeometry = inputFeature.geometry();
newGeometry = combinedClipGeom.intersection( currentGeometry );
if ( newGeometry.wkbType() == QgsWkbTypes::Unknown || QgsWkbTypes::flatType( newGeometry.wkbType() ) == QgsWkbTypes::GeometryCollection )
{
QgsGeometry intCom = inputFeature.geometry().combine( newGeometry );
QgsGeometry intSym = inputFeature.geometry().symDifference( newGeometry );
newGeometry = intCom.difference( intSym );
}
}
else
{
// clip geometry totally contains feature geometry, so no need to perform intersection
newGeometry = inputFeature.geometry();
}
if ( !QgsOverlayUtils::sanitizeIntersectionResult( newGeometry, sinkType ) )
continue;
QgsFeature outputFeature;
outputFeature.setGeometry( newGeometry );
outputFeature.setAttributes( inputFeature.attributes() );
sink->addFeature( outputFeature, QgsFeatureSink::FastInsert );
if ( singleClipFeature )
feedback->setProgress( current * step );
}
if ( !singleClipFeature )
{
// coarse progress report for multiple clip geometries
feedback->setProgress( 100.0 * static_cast< double >( i ) / clipGeoms.length() );
}
}
