static QgsExpressionContext _getExpressionContext( const void* context )
{
const QgsComposition* composition = ( const QgsComposition* ) context;
if ( !composition )
{
return QgsExpressionContext();
}
QScopedPointer< QgsExpressionContext > expContext( composition->createExpressionContext() );
return QgsExpressionContext( *expContext );
}
static QgsExpressionContext _getExpressionContext( const void* context )
{
const QgsComposerObject* composerObject = ( const QgsComposerObject* ) context;
if ( !composerObject )
{
return QgsExpressionContext();
}
QScopedPointer< QgsExpressionContext > expContext( composerObject->createExpressionContext() );
return QgsExpressionContext( *expContext );
}
QgsExpressionContext QgsSymbolsListWidget::createExpressionContext() const
{
if ( mContext.expressionContext() )
return QgsExpressionContext( *mContext.expressionContext() );
//otherwise create a default symbol context
QgsExpressionContext expContext( mContext.globalProjectAtlasMapLayerScopes( layer() ) );
// additional scopes
const auto constAdditionalExpressionContextScopes = mContext.additionalExpressionContextScopes();
for ( const QgsExpressionContextScope &scope : constAdditionalExpressionContextScopes )
{
expContext.appendScope( new QgsExpressionContextScope( scope ) );
}
expContext.setHighlightedVariables( QStringList() << QgsExpressionContext::EXPR_ORIGINAL_VALUE << QgsExpressionContext::EXPR_SYMBOL_COLOR
<< QgsExpressionContext::EXPR_GEOMETRY_PART_COUNT << QgsExpressionContext::EXPR_GEOMETRY_PART_NUM
<< QgsExpressionContext::EXPR_GEOMETRY_POINT_COUNT << QgsExpressionContext::EXPR_GEOMETRY_POINT_NUM
<< QgsExpressionContext::EXPR_CLUSTER_COLOR << QgsExpressionContext::EXPR_CLUSTER_SIZE );
return expContext;
}
QgsFieldCalculator::QgsFieldCalculator( QgsVectorLayer* vl, QWidget* parent )
: QDialog( parent )
, mVectorLayer( vl )
, mAttributeId( -1 )
{
setupUi( this );
if ( !vl )
return;
QgsExpressionContext expContext( QgsExpressionContextUtils::globalProjectLayerScopes( mVectorLayer ) );
expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "row_number" ), 1, true ) );
expContext.setHighlightedVariables( QStringList() << QStringLiteral( "row_number" ) );
builder->setLayer( vl );
builder->loadFieldNames();
builder->setExpressionContext( expContext );
populateFields();
populateOutputFieldTypes();
connect( builder, SIGNAL( expressionParsed( bool ) ), this, SLOT( setOkButtonState() ) );
connect( mOutputFieldWidthSpinBox, SIGNAL( editingFinished() ), this, SLOT( setPrecisionMinMax() ) );
QgsDistanceArea myDa;
myDa.setSourceCrs( vl->crs().srsid() );
myDa.setEllipsoidalMode( true );
myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
builder->setGeomCalculator( myDa );
//default values for field width and precision
mOutputFieldWidthSpinBox->setValue( 10 );
mOutputFieldPrecisionSpinBox->setValue( 3 );
setPrecisionMinMax();
if ( vl->providerType() == QLatin1String( "ogr" ) && vl->storageType() == QLatin1String( "ESRI Shapefile" ) )
{
mOutputFieldNameLineEdit->setMaxLength( 10 );
}
if ( !( vl->dataProvider()->capabilities() & QgsVectorDataProvider::AddAttributes ) )
{
mCreateVirtualFieldCheckbox->setChecked( true );
mCreateVirtualFieldCheckbox->setEnabled( false );
mOnlyVirtualFieldsInfoLabel->setVisible( true );
mInfoIcon->setVisible( true );
}
else
{
mOnlyVirtualFieldsInfoLabel->setVisible( false );
mInfoIcon->setVisible( false );
}
if ( !( vl->dataProvider()->capabilities() & QgsVectorDataProvider::ChangeAttributeValues ) )
{
mUpdateExistingGroupBox->setEnabled( false );
mCreateVirtualFieldCheckbox->setChecked( true );
mCreateVirtualFieldCheckbox->setEnabled( false );
}
Q_ASSERT( mNewFieldGroupBox->isEnabled() || mUpdateExistingGroupBox->isEnabled() );
if ( mNewFieldGroupBox->isEnabled() )
{
mNewFieldGroupBox->setChecked( true );
}
else
{
mNewFieldGroupBox->setToolTip( tr( "Not available for layer" ) );
mUpdateExistingGroupBox->setChecked( true );
mUpdateExistingGroupBox->setCheckable( false );
}
if ( mUpdateExistingGroupBox->isEnabled() )
{
mUpdateExistingGroupBox->setChecked( !mNewFieldGroupBox->isEnabled() );
}
else
{
mUpdateExistingGroupBox->setToolTip( tr( "Not available for layer" ) );
mNewFieldGroupBox->setChecked( true );
mNewFieldGroupBox->setCheckable( false );
}
if (( mNewFieldGroupBox->isChecked() && mCreateVirtualFieldCheckbox->isChecked() ) || mVectorLayer->isEditable() )
{
mEditModeAutoTurnOnLabel->setVisible( false );
mInfoIcon->setVisible( false );
}
else
{
mInfoIcon->setVisible( true );
}
bool hasselection = vl->selectedFeatureCount() > 0;
mOnlyUpdateSelectedCheckBox->setChecked( hasselection );
mOnlyUpdateSelectedCheckBox->setEnabled( hasselection );
mOnlyUpdateSelectedCheckBox->setText( tr( "Only update %1 selected features" ).arg( vl->selectedFeatureCount() ) );
builder->loadRecent( QStringLiteral( "fieldcalc" ) );
mInfoIcon->setPixmap( style()->standardPixmap( QStyle::SP_MessageBoxInformation ) );
setOkButtonState();
QSettings settings;
restoreGeometry( settings.value( QStringLiteral( "/Windows/QgsFieldCalculator/geometry" ) ).toByteArray() );
}
void QgsFieldCalculator::accept()
{
builder->saveToRecent( QStringLiteral( "fieldcalc" ) );
if ( !mVectorLayer )
return;
// Set up QgsDistanceArea each time we (re-)calculate
QgsDistanceArea myDa;
myDa.setSourceCrs( mVectorLayer->crs().srsid() );
myDa.setEllipsoidalMode( true );
myDa.setEllipsoid( QgsProject::instance()->ellipsoid() );
QString calcString = builder->expressionText();
QgsExpression exp( calcString );
exp.setGeomCalculator( &myDa );
exp.setDistanceUnits( QgsProject::instance()->distanceUnits() );
exp.setAreaUnits( QgsProject::instance()->areaUnits() );
QgsExpressionContext expContext( QgsExpressionContextUtils::globalProjectLayerScopes( mVectorLayer ) );
if ( !exp.prepare( &expContext ) )
{
QMessageBox::critical( nullptr, tr( "Evaluation error" ), exp.evalErrorString() );
return;
}
bool updatingGeom = false;
// Test for creating expression field based on ! mUpdateExistingGroupBox checked rather
// than on mNewFieldGroupBox checked, as if the provider does not support adding attributes
// then mUpdateExistingGroupBox is set to not checkable, and hence is not checked. This
// is a minimum fix to resolve this - better would be some GUI redesign...
if ( ! mUpdateExistingGroupBox->isChecked() && mCreateVirtualFieldCheckbox->isChecked() )
{
mVectorLayer->addExpressionField( calcString, fieldDefinition() );
}
else
{
if ( !mVectorLayer->isEditable() )
mVectorLayer->startEditing();
QApplication::setOverrideCursor( Qt::WaitCursor );
mVectorLayer->beginEditCommand( QStringLiteral( "Field calculator" ) );
//update existing field
if ( mUpdateExistingGroupBox->isChecked() || !mNewFieldGroupBox->isEnabled() )
{
if ( mExistingFieldComboBox->currentData().toString() == QLatin1String( "geom" ) )
{
//update geometry
mAttributeId = -1;
updatingGeom = true;
}
else
{
QMap<QString, int>::const_iterator fieldIt = mFieldMap.constFind( mExistingFieldComboBox->currentText() );
if ( fieldIt != mFieldMap.constEnd() )
{
mAttributeId = fieldIt.value();
}
}
}
else
{
//create new field
const QgsField newField = fieldDefinition();
if ( !mVectorLayer->addAttribute( newField ) )
{
QApplication::restoreOverrideCursor();
QMessageBox::critical( nullptr, tr( "Provider error" ), tr( "Could not add the new field to the provider." ) );
mVectorLayer->destroyEditCommand();
return;
}
//get index of the new field
const QgsFields& fields = mVectorLayer->fields();
for ( int idx = 0; idx < fields.count(); ++idx )
{
if ( fields.at( idx ).name() == mOutputFieldNameLineEdit->text() )
{
mAttributeId = idx;
break;
}
}
//update expression context with new fields
expContext.setFields( mVectorLayer->fields() );
if ( ! exp.prepare( &expContext ) )
{
QApplication::restoreOverrideCursor();
QMessageBox::critical( nullptr, tr( "Evaluation error" ), exp.evalErrorString() );
return;
}
}
if ( mAttributeId == -1 && !updatingGeom )
{
mVectorLayer->destroyEditCommand();
QApplication::restoreOverrideCursor();
return;
}
//go through all the features and change the new attribute
QgsFeature feature;
bool calculationSuccess = true;
QString error;
bool useGeometry = exp.needsGeometry();
int rownum = 1;
QgsField field = !updatingGeom ? mVectorLayer->fields().at( mAttributeId ) : QgsField();
bool newField = !mUpdateExistingGroupBox->isChecked();
QVariant emptyAttribute;
if ( newField )
emptyAttribute = QVariant( field.type() );
QgsFeatureRequest req = QgsFeatureRequest().setFlags( useGeometry ? QgsFeatureRequest::NoFlags : QgsFeatureRequest::NoGeometry );
if ( mOnlyUpdateSelectedCheckBox->isChecked() )
{
req.setFilterFids( mVectorLayer->selectedFeatureIds() );
}
QgsFeatureIterator fit = mVectorLayer->getFeatures( req );
while ( fit.nextFeature( feature ) )
{
expContext.setFeature( feature );
expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "row_number" ), rownum, true ) );
QVariant value = exp.evaluate( &expContext );
if ( exp.hasEvalError() )
{
calculationSuccess = false;
error = exp.evalErrorString();
break;
}
else if ( updatingGeom )
{
if ( value.canConvert< QgsGeometry >() )
{
QgsGeometry geom = value.value< QgsGeometry >();
mVectorLayer->changeGeometry( feature.id(), geom );
}
}
else
{
field.convertCompatible( value );
mVectorLayer->changeAttributeValue( feature.id(), mAttributeId, value, newField ? emptyAttribute : feature.attributes().value( mAttributeId ) );
}
rownum++;
}
QApplication::restoreOverrideCursor();
if ( !calculationSuccess )
{
QMessageBox::critical( nullptr, tr( "Error" ), tr( "An error occurred while evaluating the calculation string:\n%1" ).arg( error ) );
mVectorLayer->destroyEditCommand();
return;
}
mVectorLayer->endEditCommand();
}
QDialog::accept();
}
