QgsExpressionContext QgsExpressionContextUtils::createFeatureBasedContext( const QgsFeature &feature, const QgsFields &fields )
{
QgsExpressionContextScope* scope = new QgsExpressionContextScope();
scope->setFeature( feature );
scope->setFields( fields );
return QgsExpressionContext() << scope;
}
QgsExpressionContextScope* QgsExpressionContextUtils::atlasScope( const QgsAtlasComposition* atlas )
{
QgsExpressionContextScope* scope = new QgsExpressionContextScope( QObject::tr( "Atlas" ) );
if ( !atlas )
{
//add some dummy atlas variables. This is done so that as in certain contexts we want to show
//users that these variables are available even if they have no current value
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_pagename", QString(), true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_feature", QVariant::fromValue( QgsFeature() ), true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_featureid", 0, true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_geometry", QVariant::fromValue( QgsGeometry() ), true ) );
return scope;
}
//add known atlas variables
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_totalfeatures", atlas->numFeatures(), true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_featurenumber", atlas->currentFeatureNumber() + 1, true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_filename", atlas->currentFilename(), true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_pagename", atlas->currentPageName(), true ) );
if ( atlas->enabled() && atlas->coverageLayer() )
{
scope->setFields( atlas->coverageLayer()->fields() );
}
if ( atlas->enabled() )
{
QgsFeature atlasFeature = atlas->feature();
scope->setFeature( atlasFeature );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_feature", QVariant::fromValue( atlasFeature ), true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_featureid", atlasFeature.id(), true ) );
scope->addVariable( QgsExpressionContextScope::StaticVariable( "atlas_geometry", QVariant::fromValue( *atlasFeature.constGeometry() ), true ) );
}
return scope;
}
