23QString QgsGeometryByExpressionAlgorithm::name()
const
25 return QStringLiteral(
"geometrybyexpression" );
28QString QgsGeometryByExpressionAlgorithm::displayName()
const
30 return QObject::tr(
"Geometry by expression" );
33QStringList QgsGeometryByExpressionAlgorithm::tags()
const
35 return QObject::tr(
"geometry,expression,create,modify,update" ).split(
',' );
38QString QgsGeometryByExpressionAlgorithm::group()
const
40 return QObject::tr(
"Vector geometry" );
43QString QgsGeometryByExpressionAlgorithm::groupId()
const
45 return QStringLiteral(
"vectorgeometry" );
48QString QgsGeometryByExpressionAlgorithm::outputName()
const
50 return QObject::tr(
"Modified geometry" );
53QString QgsGeometryByExpressionAlgorithm::shortHelpString()
const
55 return QObject::tr(
"This algorithm updates existing geometries (or creates new geometries) for input "
56 "features by use of a QGIS expression. This allows complex geometry modifications "
57 "which can utilize all the flexibility of the QGIS expression engine to manipulate "
58 "and create geometries for output features.\n\n"
59 "For help with QGIS expression functions, see the inbuilt help for specific functions "
60 "which is available in the expression builder." );
63QgsGeometryByExpressionAlgorithm *QgsGeometryByExpressionAlgorithm::createInstance()
const
65 return new QgsGeometryByExpressionAlgorithm();
68QList<int> QgsGeometryByExpressionAlgorithm::inputLayerTypes()
const
83void QgsGeometryByExpressionAlgorithm::initParameters(
const QVariantMap & )
86 QStringList() << QObject::tr(
"Polygon" ) << QObject::tr(
"Line" ) << QObject::tr(
"Point" ),
false, 0 ) );
90 QStringLiteral(
"@geometry" ), QStringLiteral(
"INPUT" ) ) );
95 const int geometryType = parameterAsInt( parameters, QStringLiteral(
"OUTPUT_GEOMETRY" ), context );
96 switch ( geometryType )
109 if ( parameterAsBoolean( parameters, QStringLiteral(
"WITH_Z" ), context ) )
113 if ( parameterAsBoolean( parameters, QStringLiteral(
"WITH_M" ), context ) )
118 mExpression =
QgsExpression( parameterAsString( parameters, QStringLiteral(
"EXPRESSION" ), context ) );
119 if ( mExpression.hasParserError() )
121 feedback->
reportError( mExpression.parserErrorString() );
125 mExpressionContext = createExpressionContext( parameters, context );
126 mExpression.prepare( &mExpressionContext );
134 mExpressionContext.setFeature( feature );
135 const QVariant value = mExpression.evaluate( &mExpressionContext );
137 if ( mExpression.hasEvalError() )
139 throw QgsProcessingException( QObject::tr(
"Evaluation error: %1" ).arg( mExpression.evalErrorString() ) );
148 if ( value.userType() == qMetaTypeId< QgsGeometry>() )
@ Vector
Tables (i.e. vector layers with or without geometry). When used for a sink this indicates the sink ha...
@ SkipGeometryValidityChecks
Invalid geometry checks should always be skipped. This flag can be useful for algorithms which always...
WkbType
The WKB type describes the number of dimensions a geometry has.
QFlags< ProcessingFeatureSourceFlag > ProcessingFeatureSourceFlags
Flags which control how QgsProcessingFeatureSource fetches features.
Class for parsing and evaluation of expressions (formerly called "search strings").
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
A geometry is the spatial representation of a feature.
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.
virtual void reportError(const QString &error, bool fatalError=false)
Reports that the algorithm encountered an error while executing.
A boolean parameter for processing algorithms.
An enum based parameter for processing algorithms, allowing for selection from predefined values.
An expression parameter for processing algorithms.
static bool isNull(const QVariant &variant, bool silenceNullWarnings=false)
Returns true if the specified variant should be considered a NULL value.
static Qgis::WkbType addM(Qgis::WkbType type)
Adds the m dimension to a WKB type and returns the new type.
static Qgis::WkbType addZ(Qgis::WkbType type)
Adds the z dimension to a WKB type and returns the new type.
QList< QgsFeature > QgsFeatureList