24QString QgsDifferenceAlgorithm::name()
const
26 return QStringLiteral(
"difference" );
29QString QgsDifferenceAlgorithm::displayName()
const
31 return QObject::tr(
"Difference" );
34QStringList QgsDifferenceAlgorithm::tags()
const
36 return QObject::tr(
"difference,erase,not overlap" ).split(
',' );
39QString QgsDifferenceAlgorithm::group()
const
41 return QObject::tr(
"Vector overlay" );
44QString QgsDifferenceAlgorithm::groupId()
const
46 return QStringLiteral(
"vectoroverlay" );
49QString QgsDifferenceAlgorithm::shortHelpString()
const
51 return QObject::tr(
"This algorithm extracts features from the Input layer that fall outside, or partially overlap, features in the Overlay layer. "
52 "Input layer features that partially overlap feature(s) in the Overlay layer are split along those features' boundary "
53 "and only the portions outside the Overlay layer features are retained." )
54 + QStringLiteral(
"\n\n" )
55 + QObject::tr(
"Attributes are not modified, although properties such as area or length of the features will "
56 "be modified by the difference operation. If such properties are stored as attributes, those attributes will have to "
57 "be manually updated." );
60bool QgsDifferenceAlgorithm::supportInPlaceEdit(
const QgsMapLayer *l )
const
62 const QgsVectorLayer *layer = qobject_cast< const QgsVectorLayer * >( l );
78 return new QgsDifferenceAlgorithm();
81void QgsDifferenceAlgorithm::initAlgorithm(
const QVariantMap & )
87 std::unique_ptr< QgsProcessingParameterNumber > gridSize = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral(
"GRID_SIZE" ),
90 addParameter( gridSize.release() );
96 std::unique_ptr< QgsFeatureSource > sourceA( parameterAsSource( parameters, QStringLiteral(
"INPUT" ), context ) );
100 const std::unique_ptr< QgsFeatureSource > sourceB( parameterAsSource( parameters, QStringLiteral(
"OVERLAY" ), context ) );
107 std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral(
"OUTPUT" ), context, dest, sourceA->fields(), geomType, sourceA->sourceCrs() ) );
112 outputs.insert( QStringLiteral(
"OUTPUT" ), dest );
115 const long total = sourceA->featureCount();
118 if ( parameters.value( QStringLiteral(
"GRID_SIZE" ) ).isValid() )
120 geometryParameters.
setGridSize( parameterAsDouble( parameters, QStringLiteral(
"GRID_SIZE" ), context ) );
123 QgsOverlayUtils::difference( *sourceA, *sourceB, *sink, context, feedback, count, total, QgsOverlayUtils::OutputA, geometryParameters, QgsOverlayUtils::SanitizeFlag::DontPromotePointGeometryToMultiPoint );
QFlags< ProcessingAlgorithmFlag > ProcessingAlgorithmFlags
Flags indicating how and when an algorithm operates and should be exposed to users.
WkbType
The WKB type describes the number of dimensions a geometry has.
@ SupportsInPlaceEdits
Algorithm supports in-place editing.
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
@ Double
Double/float values.
Encapsulates parameters under which a geometry operation is performed.
void setGridSize(double size)
Sets the grid size which will be used to snap vertices of a geometry.
Base class for all map layer types.
Abstract base class for processing algorithms.
virtual Qgis::ProcessingAlgorithmFlags flags() const
Returns the flags indicating how and when the algorithm operates and should be exposed to users.
Contains information about the context in which a processing algorithm is executed.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
A feature sink output for processing algorithms.
An input feature source (such as vector layers) parameter for processing algorithms.
Represents a vector layer which manages a vector based data sets.
bool isSpatial() const FINAL
Returns true if this is a geometry layer and false in case of NoGeometry (table only) or UnknownGeome...
static Qgis::WkbType promoteNonPointTypesToMulti(Qgis::WkbType type)
Promotes a WKB geometry type to its multi-type equivalent, with the exception of point geometry types...