Manages snapping grids and preset snap lines in a layout, and handles snapping points to the nearest grid coordinate/snap line when possible. More...

#include <qgslayoutsnapper.h>

Inheritance diagram for QgsLayoutSnapper:

[legend]

Public Member Functions
	QgsLayoutSnapper (QgsLayout *layout)
	Constructor for QgsLayoutSnapper, attached to the specified layout. More...

QgsLayout *	layout () override
	Returns the layout the object belongs to. More...

bool	readXml (const QDomElement &gridElement, const QDomDocument &document, const QgsReadWriteContext &context) override
	Sets the snapper's state from a DOM element. More...

void	setSnapToGrid (bool enabled)
	Sets whether snapping to grid is enabled. More...

void	setSnapToGuides (bool enabled)
	Sets whether snapping to guides is enabled. More...

void	setSnapToItems (bool enabled)
	Sets whether snapping to items is enabled. More...

void	setSnapTolerance (int snapTolerance)
	Sets the snap tolerance (in pixels) to use when snapping. More...

QPointF	snapPoint (QPointF point, double scaleFactor, bool &snapped, QGraphicsLineItem horizontalSnapLine=nullptr, QGraphicsLineItem verticalSnapLine=nullptr, const QList< QgsLayoutItem * > *ignoreItems=nullptr) const
	Snaps a layout coordinate point. More...

QPointF	snapPointsToGrid (const QList< QPointF > &points, double scaleFactor, bool &snappedX, bool &snappedY) const
	Snaps a set of points to the grid. More...

double	snapPointsToGuides (const QList< double > &points, Qt::Orientation orientation, double scaleFactor, bool &snapped) const
	Snaps a set of points to the guides. More...

double	snapPointsToItems (const QList< double > &points, Qt::Orientation orientation, double scaleFactor, const QList< QgsLayoutItem * > &ignoreItems, bool &snapped, QGraphicsLineItem *snapLine=nullptr) const
	Snaps a set of points to the item bounds. More...

QPointF	snapPointToGrid (QPointF point, double scaleFactor, bool &snappedX, bool &snappedY) const
	Snaps a layout coordinate point to the grid. More...

double	snapPointToGuides (double original, Qt::Orientation orientation, double scaleFactor, bool &snapped) const
	Snaps an original layout coordinate to the guides. More...

double	snapPointToItems (double original, Qt::Orientation orientation, double scaleFactor, const QList< QgsLayoutItem * > &ignoreItems, bool &snapped, QGraphicsLineItem *snapLine=nullptr) const
	Snaps an original layout coordinate to the item bounds. More...

QRectF	snapRect (const QRectF &rect, double scaleFactor, bool &snapped, QGraphicsLineItem horizontalSnapLine=nullptr, QGraphicsLineItem verticalSnapLine=nullptr, const QList< QgsLayoutItem * > *ignoreItems=nullptr) const
	Snaps a layout coordinate rect. More...

bool	snapToGrid () const
	Returns true if snapping to grid is enabled. More...

bool	snapToGuides () const
	Returns true if snapping to guides is enabled. More...

bool	snapToItems () const
	Returns true if snapping to items is enabled. More...

int	snapTolerance () const
	Returns the snap tolerance (in pixels) to use when snapping. More...

QString	stringType () const override
	Returns the object type as a string. More...

bool	writeXml (QDomElement &parentElement, QDomDocument &document, const QgsReadWriteContext &context) const override
	Stores the snapper's state in a DOM element. More...

Public Member Functions inherited from QgsLayoutSerializableObject
QgsAbstractLayoutUndoCommand *	createCommand (const QString &text, int id, QUndoCommand *parent=nullptr) override
	Creates a new layout undo command with the specified text and parent. More...

Public Member Functions inherited from QgsLayoutUndoObjectInterface
virtual	~QgsLayoutUndoObjectInterface ()=default
	Destructor for QgsLayoutUndoObjectInterface. More...

Friends
class	QgsLayoutSnapperUndoCommand

Detailed Description

Manages snapping grids and preset snap lines in a layout, and handles snapping points to the nearest grid coordinate/snap line when possible.

Since: QGIS 3.0

Definition at line 36 of file qgslayoutsnapper.h.

Constructor & Destructor Documentation

QgsLayoutSnapper::QgsLayoutSnapper ( QgsLayout * layout )

Constructor for QgsLayoutSnapper, attached to the specified layout.

Definition at line 24 of file qgslayoutsnapper.cpp.

Member Function Documentation

QgsLayout * QgsLayoutSnapper::layout ( )

overridevirtual

Returns the layout the object belongs to.

Implements QgsLayoutSerializableObject.

Definition at line 31 of file qgslayoutsnapper.cpp.

bool QgsLayoutSnapper::readXml	(	const QDomElement &	gridElement,
		const QDomDocument &	document,
		const QgsReadWriteContext &	context
	)

overridevirtual

Sets the snapper's state from a DOM element.

snapperElement is the DOM node corresponding to the snapper.

See also: writeXml()

Implements QgsLayoutSerializableObject.

Definition at line 433 of file qgslayoutsnapper.cpp.

void QgsLayoutSnapper::setSnapToGrid ( bool enabled )

Sets whether snapping to grid is enabled.

See also: snapToGrid()

Definition at line 41 of file qgslayoutsnapper.cpp.

void QgsLayoutSnapper::setSnapToGuides ( bool enabled )

Sets whether snapping to guides is enabled.

See also: snapToGuides()

Definition at line 46 of file qgslayoutsnapper.cpp.

void QgsLayoutSnapper::setSnapToItems ( bool enabled )

Sets whether snapping to items is enabled.

See also: snapToItems()

Definition at line 51 of file qgslayoutsnapper.cpp.

void QgsLayoutSnapper::setSnapTolerance ( int snapTolerance )

Sets the snap tolerance (in pixels) to use when snapping.

See also: snapTolerance()

Definition at line 36 of file qgslayoutsnapper.cpp.

QPointF QgsLayoutSnapper::snapPoint	(	QPointF	point,
		double	scaleFactor,
		bool &	snapped,
		QGraphicsLineItem *	horizontalSnapLine = `nullptr`,
		QGraphicsLineItem *	verticalSnapLine = `nullptr`,
		const QList< QgsLayoutItem * > *	ignoreItems = `nullptr`
	)		const

Snaps a layout coordinate point.

If point was snapped, snapped will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

This method considers snapping to the grid, snap lines, etc.

If the horizontalSnapLine and verticalSnapLine arguments are specified, then the snapper will automatically display and position these lines to indicate snapping positions to item bounds.

A list of items to ignore during the snapping can be specified via the ignoreItems list.

See also: snapRect()

Definition at line 56 of file qgslayoutsnapper.cpp.

QPointF QgsLayoutSnapper::snapPointsToGrid	(	const QList< QPointF > &	points,
		double	scaleFactor,
		bool &	snappedX,
		bool &	snappedY
	)		const

Snaps a set of points to the grid.

If the points were snapped, snapped will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

If snapToGrid() is disabled, this method will not attempt to snap the points.

The returned value is the smallest delta which the points need to be shifted by in order to align one of the points to the grid.

See also: snapPointToGrid()

Definition at line 195 of file qgslayoutsnapper.cpp.

double QgsLayoutSnapper::snapPointsToGuides	(	const QList< double > &	points,
		Qt::Orientation	orientation,
		double	scaleFactor,
		bool &	snapped
	)		const

Snaps a set of points to the guides.

If the points were snapped, snapped will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

If snapToGuides() is disabled, this method will not attempt to snap the points.

The returned value is the smallest delta which the points need to be shifted by in order to align one of the points to a guide.

See also: snapPointToGuides()

Definition at line 269 of file qgslayoutsnapper.cpp.

double QgsLayoutSnapper::snapPointsToItems	(	const QList< double > &	points,
		Qt::Orientation	orientation,
		double	scaleFactor,
		const QList< QgsLayoutItem * > &	ignoreItems,
		bool &	snapped,
		QGraphicsLineItem *	snapLine = `nullptr`
	)		const

Snaps a set of points to the item bounds.

If the points were snapped, snapped will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

If snapToItems() is disabled, this method will not attempt to snap the points.

The returned value is the smallest delta which the points need to be shifted by in order to align one of the points to an item bound.

See also: snapPointToItems()

Definition at line 315 of file qgslayoutsnapper.cpp.

QPointF QgsLayoutSnapper::snapPointToGrid	(	QPointF	point,
		double	scaleFactor,
		bool &	snappedX,
		bool &	snappedY
	)		const

Snaps a layout coordinate point to the grid.

If point was snapped horizontally, snappedX will be set to true. If point was snapped vertically, snappedY will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

If snapToGrid() is disabled, this method will return the point unchanged.

See also: snapPointsToGrid()

Definition at line 189 of file qgslayoutsnapper.cpp.

double QgsLayoutSnapper::snapPointToGuides	(	double	original,
		Qt::Orientation	orientation,
		double	scaleFactor,
		bool &	snapped
	)		const

Snaps an original layout coordinate to the guides.

If the point was snapped, snapped will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

If snapToGuides() is disabled, this method will return the point unchanged.

See also: snapPointsToGuides()

Definition at line 263 of file qgslayoutsnapper.cpp.

double QgsLayoutSnapper::snapPointToItems	(	double	original,
		Qt::Orientation	orientation,
		double	scaleFactor,
		const QList< QgsLayoutItem * > &	ignoreItems,
		bool &	snapped,
		QGraphicsLineItem *	snapLine = `nullptr`
	)		const

Snaps an original layout coordinate to the item bounds.

If the point was snapped, snapped will be set to true.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

If snapToItems() is disabled, this method will return the point unchanged.

A list of items to ignore during the snapping can be specified via the ignoreItems list.

If snapLine is specified, the snapper will automatically show (or hide) the snap line based on the result of the snap, and position it at the correct location for the snap.

See also: snapPointsToItems()

Definition at line 308 of file qgslayoutsnapper.cpp.

QRectF QgsLayoutSnapper::snapRect	(	const QRectF &	rect,
		double	scaleFactor,
		bool &	snapped,
		QGraphicsLineItem *	horizontalSnapLine = `nullptr`,
		QGraphicsLineItem *	verticalSnapLine = `nullptr`,
		const QList< QgsLayoutItem * > *	ignoreItems = `nullptr`
	)		const

Snaps a layout coordinate rect.

If rect was snapped, snapped will be set to true.

Snapping occurs by moving the rectangle alone. The rectangle will not be resized as a result of the snap operation.

The scaleFactor argument should be set to the transformation from scalar transform from layout coordinates to pixels, i.e. the graphics view transform().m11() value.

This method considers snapping to the grid, snap lines, etc.

If the horizontalSnapLine and verticalSnapLine arguments are specified, then the snapper will automatically display and position these lines to indicate snapping positions to item bounds.

A list of items to ignore during the snapping can be specified via the ignoreItems list.