QGIS/python/core/layertree/qgslayertreeutils.sip
Hugo Mercier d16cdcf449 Add more options for filtering legend elements
This introduces two new options to filter legend elements:
- filter by expression: a boolean expression can be set. Only symbols of
features that make the expression evaluated to true will be kept in the legend
- filter by polygon: only symbols of features that are inside the given
polygon will be part of the legend.

The polygon filtering is used in particular for a new option in the
composer legend that allows to filter out anything that is not included
in the current atlas polygon.
2015-11-03 10:39:09 +01:00

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/**
* Assorted functions for dealing with layer trees.
*
* @note added in 2.4
*/
class QgsLayerTreeUtils
{
%TypeHeaderCode
#include <qgslayertreeutils.h>
%End
public:
//! Try to load layer tree from \verbatim <legend> \endverbatim tag from project files from QGIS 2.2 and below
static bool readOldLegend( QgsLayerTreeGroup* root, const QDomElement& legendElem );
//! Try to load custom layer order from \verbatim <legend> \endverbatim tag from project files from QGIS 2.2 and below
static bool readOldLegendLayerOrder( const QDomElement& legendElem, bool& hasCustomOrder, QStringList& order );
//! Return \verbatim <legend> \endverbatim tag used in QGIS 2.2 and below
static QDomElement writeOldLegend( QDomDocument& doc, QgsLayerTreeGroup* root, bool hasCustomOrder, const QStringList& order );
//! Convert Qt::CheckState to QString
static QString checkStateToXml( Qt::CheckState state );
//! Convert QString to Qt::CheckState
static Qt::CheckState checkStateFromXml( const QString& txt );
//! Return true if any of the layers is editable
static bool layersEditable( const QList<QgsLayerTreeLayer*>& layerNodes );
//! Return true if any of the layers is modified
static bool layersModified( const QList<QgsLayerTreeLayer*>& layerNodes );
//! Remove layer nodes that refer to invalid layers
static void removeInvalidLayers( QgsLayerTreeGroup* group );
//! Remove subtree of embedded groups and replaces it with a custom property embedded-visible-layers
static void replaceChildrenOfEmbeddedGroups( QgsLayerTreeGroup* group );
//! get invisible layers
static QStringList invisibleLayerList( QgsLayerTreeNode *node );
//! Set the expression filter of a legend layer
static void setLegendFilterByExpression( QgsLayerTreeLayer& layer, const QString& expr, bool enabled = true );
//! Return the expression filter of a legend layer
static QString legendFilterByExpression( const QgsLayerTreeLayer& layer, bool* enabled = 0 );
//! Test if one of the layers in a group has an expression filter
static bool hasLegendFilterExpression( const QgsLayerTreeGroup& group );
};