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.
	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.
int	snapToBackgroundLayers (const QPoint &p, QList< QgsSnappingResult > &results, const QList< QgsPoint > &excludePoints=QList< QgsPoint >())
	Snaps to the background layers.
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

canvas

the 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

p	start point of the snap (in pixel coordinates)
results	snapped points
excludePoints	a 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

p	start point of the snap (in pixel coordinates)
results	list to which the results are appended
snap_to	snap to vertex or to segment
snappingTol	snapping tolerance. -1 means that the search radius for vertex edits is taken
excludePoints	a 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

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

• /tmp/buildd/qgis-2.6.0+wheezy1/src/gui/qgsmapcanvassnapper.h
• /tmp/buildd/qgis-2.6.0+wheezy1/src/gui/qgsmapcanvassnapper.cpp