QGIS API Documentation  2.5.0-Master
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Properties Friends Macros Groups Pages
Public Member Functions | List of all members
QgsMapCanvasSnapper Class Reference

This class reads the snapping properties from the current project and configures a QgsSnapper to perform the snapping. More...

#include <qgsmapcanvassnapper.h>

Public Member Functions

 QgsMapCanvasSnapper (QgsMapCanvas *canvas)
 Constructor. More...
 
 QgsMapCanvasSnapper ()
 
 ~QgsMapCanvasSnapper ()
 
int snapToCurrentLayer (const QPoint &p, QList< QgsSnappingResult > &results, QgsSnapper::SnappingType snap_to, double snappingTol=-1, const QList< QgsPoint > &excludePoints=QList< QgsPoint >())
 Does a snap to the current layer. More...
 
int snapToBackgroundLayers (const QPoint &p, QList< QgsSnappingResult > &results, const QList< QgsPoint > &excludePoints=QList< QgsPoint >())
 Snaps to the background layers. More...
 
void setMapCanvas (QgsMapCanvas *canvas)
 

Detailed Description

This class reads the snapping properties from the current project and configures a QgsSnapper to perform the snapping.

Snapping can be done to the active layer (useful for selecting a vertex to manipulate) or to background layers

Constructor & Destructor Documentation

QgsMapCanvasSnapper::QgsMapCanvasSnapper ( QgsMapCanvas canvas)

Constructor.

Parameters
canvasthe map canvas to snap to
QgsMapCanvasSnapper::QgsMapCanvasSnapper ( )
QgsMapCanvasSnapper::~QgsMapCanvasSnapper ( )

Member Function Documentation

void QgsMapCanvasSnapper::setMapCanvas ( QgsMapCanvas canvas)
int QgsMapCanvasSnapper::snapToBackgroundLayers ( const QPoint &  p,
QList< QgsSnappingResult > &  results,
const QList< QgsPoint > &  excludePoints = QList<QgsPoint>() 
)

Snaps to the background layers.

This method is useful to align the features of the edited layers to those of other layers (as described in the project properties). Uses snap mode QgsSnapper::SnapWithOneResult. Therefore, only the closest result is returned.

Parameters
pstart point of the snap (in pixel coordinates)
resultssnapped points
excludePointsa list with (map coordinate) points that should be excluded in the snapping result. Useful e.g. for vertex moves where a vertex should not be snapped to its original position
Returns
0 in case of success
int QgsMapCanvasSnapper::snapToCurrentLayer ( const QPoint &  p,
QList< QgsSnappingResult > &  results,
QgsSnapper::SnappingType  snap_to,
double  snappingTol = -1,
const QList< QgsPoint > &  excludePoints = QList<QgsPoint>() 
)

Does a snap to the current layer.

Uses snap mode QgsSnapper::SnapWithResultsForSamePosition if topological editing is enabled and QgsSnapper::SnapWithOneResult_BY_SEGMENT if not. As this method is usually used to find vertices/segments for editing operations, it uses the search radius for vertex editing from the qgis options.

Parameters
pstart point of the snap (in pixel coordinates)
resultslist to which the results are appended
snap_tosnap to vertex or to segment
snappingTolsnapping tolerance. -1 means that the search radius for vertex edits is taken
excludePointsa list with (map coordinate) points that should be excluded in the snapping result. Useful e.g. for vertex moves where a vertex should not be snapped to its original position

The documentation for this class was generated from the following files: