/**
 * The QgsLayerTreeMapCanvasBridge class takes care of updates of layer set
 * for QgsMapCanvas from a layer tree. The class listens to the updates in the layer tree
 * and updates the list of layers for rendering whenever some layers are added, removed,
 * or their visibility changes.
 *
 * The update of layers is not done immediately - it is postponed, so a series of updates
 * to the layer tree will trigger just one update of canvas layers.
 *
 * Also allows the client to override the default order of layers. This is useful
 * in advanced cases where the grouping in layer tree should be independent from the actual
 * order in the canvas.
 *
 * @note added in 2.4
 */
class QgsLayerTreeMapCanvasBridge : QObject
{
%TypeHeaderCode
#include <qgslayertreemapcanvasbridge.h>
%End

  public:
    //! Constructor: does not take ownership of the layer tree nor canvas
    QgsLayerTreeMapCanvasBridge( QgsLayerTree* root, QgsMapCanvas* canvas, QObject* parent /TransferThis/ = 0 );

    QgsLayerTree *rootGroup() const;
    QgsMapCanvas *mapCanvas() const;

    //! Associates overview canvas with the bridge, so the overview will be updated whenever main canvas is updated
    //! @note added in 3.0
    void setOvervewCanvas( QgsMapOverviewCanvas* overviewCanvas );
    //! Returns associated overview canvas (may be null)
    //! @note added in 3.0
    QgsMapOverviewCanvas *overviewCanvas() const;

    //! if enabled, will automatically set full canvas extent and destination CRS + map units
    //! when first layer(s) are added
    void setAutoSetupOnFirstLayer( bool enabled );
    bool autoSetupOnFirstLayer() const;

    void setCanvasLayers();

  signals:
    void canvasLayersChanged( const QList< QgsMapLayer* >& layers );

};