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Implement GROUP_EXPRESSION instead of GROUP_FIELD

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to allow for flexible grouping without the need for an intermediate field calculation.
This commit is contained in:
uclaros 2020-11-14 21:59:10 +02:00 committed by Nyall Dawson
parent 280d2e5914
commit e35f8757b1
1 changed files with 19 additions and 17 deletions
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36
src/analysis/processing/qgsalgorithmpointstolines.cpp
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@ -65,8 +65,8 @@ void QgsPointsToLinesAlgorithm::initAlgorithm( const QVariantMap & )
QObject::tr( "Order expression" ), QVariant(), QStringLiteral( "INPUT" ), true ) );
addParameter( new QgsProcessingParameterBoolean( QStringLiteral( "NATURAL_SORT" ),
QObject::tr( "Sort text containing numbers naturally" ), false, true ) );
addParameter( new QgsProcessingParameterField( QStringLiteral( "GROUP_FIELD" ),
QObject::tr( "Line group field" ), QVariant(), QStringLiteral( "INPUT" ), QgsProcessingParameterField::Any, false, true ) );
addParameter( new QgsProcessingParameterExpression( QStringLiteral( "GROUP_EXPRESSION" ),
QObject::tr( "Line group expression" ), QVariant(), QStringLiteral( "INPUT" ), true ) );
addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ),
QObject::tr( "Lines" ), QgsProcessing::TypeVectorLine ) );
addOutput( new QgsProcessingOutputNumber( QStringLiteral( "NUM_LINES" ), QObject::tr( "Number of lines" ) ) );
@ -85,24 +85,27 @@ QVariantMap QgsPointsToLinesAlgorithm::processAlgorithm( const QVariantMap &para
const bool closeLines = parameterAsBool( parameters, QStringLiteral( "CLOSE_LINES" ), context );
QString orderExpression = parameterAsString( parameters, QStringLiteral( "ORDER_EXPRESSION" ), context );
QString orderExpressionString = parameterAsString( parameters, QStringLiteral( "ORDER_EXPRESSION" ), context );
// If no order expression is given, default to the fid
if ( orderExpression.isEmpty() )
orderExpression = QString( "$id" );
if ( orderExpressionString.isEmpty() )
orderExpressionString = QString( "$id" );
QgsExpressionContext expressionContext = createExpressionContext( parameters, context, source.get() );
QgsExpression expression = QgsExpression( orderExpression );
if ( expression.hasParserError() )
throw QgsProcessingException( expression.parserErrorString() );
QgsExpression orderExpression = QgsExpression( orderExpressionString );
if ( orderExpression.hasParserError() )
throw QgsProcessingException( orderExpression.parserErrorString() );
QStringList requiredFields = QStringList( expression.referencedColumns().values() );
expression.prepare( &expressionContext );
QStringList requiredFields = QStringList( orderExpression.referencedColumns().values() );
orderExpression.prepare( &expressionContext );
QgsFields outputFields = QgsFields();
const QString groupField = parameterAsString( parameters, QStringLiteral( "GROUP_FIELD" ), context );
if ( ! groupField.isEmpty() )
QString groupExpressionString = parameterAsString( parameters, QStringLiteral( "GROUP_EXPRESSION" ), context );
QgsExpression groupExpression = QgsExpression( groupExpressionString );
if ( groupExpression.hasParserError() )
throw QgsProcessingException( groupExpression.parserErrorString() );
if ( ! groupExpressionString.isEmpty() )
{
const QgsField field = source->fields().field( groupField );
requiredFields.append( field.name() );
requiredFields.append( groupExpression.referencedColumns().values() );
const QgsField field = groupExpression.isField() ? source->fields().field( requiredFields.last() ) : QString( "group" );
outputFields.append( field );
}
@ -141,10 +144,9 @@ QVariantMap QgsPointsToLinesAlgorithm::processAlgorithm( const QVariantMap &para
if ( f.hasGeometry() && ! f.geometry().isNull() )
{
expressionContext.setFeature( f );
const QVariant orderValue = expression.evaluate( &expressionContext );
const QVariant orderValue = orderExpression.evaluate( &expressionContext );
const QVariant groupValue = groupExpressionString.isEmpty() ? QVariant() : groupExpression.evaluate( &expressionContext );
// If no group field is specified then an invalid QVariant is returned, we're ok with that as our only group
const QVariant groupValue = f.attribute( groupField );
if ( ! allPoints.keys().contains( groupValue ) )
allPoints[ groupValue ] = QVector< QPair< QVariant, const QgsPoint * > >();
const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( f.geometry().constGet()->clone() );