A helper class for translating a series of points. More...

#include <qwt_point_mapper.h>

Classes
class	PrivateData

Public Types
enum	TransformationFlag { RoundPoints = 0x01 , WeedOutPoints = 0x02 , WeedOutIntermediatePoints = 0x04 }
	Flags affecting the transformation process. More...

Public Member Functions
	QwtPointMapper ()
	Constructor.

	~QwtPointMapper ()
	Destructor.

void	setFlags (TransformationFlags)
	Set the flags affecting the transformation process.

TransformationFlags	flags () const

void	setFlag (TransformationFlag, bool on=true)
	Modify a flag affecting the transformation process.

bool	testFlag (TransformationFlag) const

void	setBoundingRect (const QRectF &)
	Set a bounding rectangle for the point mapping algorithm.

QRectF	boundingRect () const

QPolygonF	toPolygonF (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtSeriesData< QPointF > *series, int from, int to) const
	Translate a series of points into a QPolygonF.

QPolygon	toPolygon (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtSeriesData< QPointF > *series, int from, int to) const
	Translate a series of points into a QPolygon.

QPolygon	toPoints (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtSeriesData< QPointF > *series, int from, int to) const
	Translate a series of points into a QPolygon.

QPolygonF	toPointsF (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtSeriesData< QPointF > *series, int from, int to) const
	Translate a series into a QPolygonF.

QImage	toImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtSeriesData< QPointF > *series, int from, int to, const QPen &, bool antialiased, uint numThreads) const
	Translate a series into a QImage.

Detailed Description

A helper class for translating a series of points.

QwtPointMapper is a collection of methods and optimizations for translating a series of points into paint device coordinates. It is used by QwtPlotCurve but might also be useful for similar plot items displaying a QwtSeriesData<QPointF>.

Member Enumeration Documentation

◆ TransformationFlag

enum QwtPointMapper::TransformationFlag

Flags affecting the transformation process.

See also: setFlag(), setFlags()

Enumerator

RoundPoints

Round points to integer values.

WeedOutPoints

Try to remove points, that are translated to the same position.

WeedOutIntermediatePoints

An even more aggressive weeding algorithm, that can be used in toPolygon().

A consecutive chunk of points being mapped to the same x coordinate is reduced to 4 points:

first point
point with the minimum y coordinate
point with the maximum y coordinate
last point

In the worst case ( first and last points are never one of the extremes ) the number of points will be 4 times the width.

As the algorithm is fast it can be used inside of a polyline render cycle.

Member Function Documentation

◆ boundingRect()

QRectF QwtPointMapper::boundingRect ( ) const

Returns: Bounding rectangle

See also: setBoundingRect()

◆ flags()

QwtPointMapper::TransformationFlags QwtPointMapper::flags ( ) const

Returns: Flags affecting the transformation process

See also: setFlags(), setFlag()

◆ setBoundingRect()

void QwtPointMapper::setBoundingRect ( const QRectF & rect )

Set a bounding rectangle for the point mapping algorithm.

A valid bounding rectangle can be used for optimizations

Parameters

rect	Bounding rectangle

See also: boundingRect()

◆ setFlag()

void QwtPointMapper::setFlag	(	TransformationFlag	flag,
		bool	on = `true`
	)

Modify a flag affecting the transformation process.

Parameters

flag	Flag type
on	Value

See also: flag(), setFlags()

◆ setFlags()

void QwtPointMapper::setFlags ( TransformationFlags flags )

Set the flags affecting the transformation process.

Parameters

flags Flags

See also: flags(), setFlag()

◆ testFlag()

bool QwtPointMapper::testFlag ( TransformationFlag flag ) const

Returns: True, when the flag is set

Parameters

flag Flag type

See also: setFlag(), setFlags()

◆ toImage()

QImage QwtPointMapper::toImage	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QwtSeriesData< QPointF > *	series,
		int	from,
		int	to,
		const QPen &	pen,
		bool	antialiased,
		uint	numThreads
	)		const

Translate a series into a QImage.

Parameters

xMap	x map
yMap	y map
series	Series of points to be mapped
from	Index of the first point to be painted
to	Index of the last point to be painted
pen	Pen used for drawing a point of the image, where a point is mapped to
antialiased	True, when the dots should be displayed antialiased
numThreads	Number of threads to be used for rendering. If numThreads is set to 0, the system specific ideal thread count is used.

Returns: Image displaying the series

◆ toPoints()

QPolygon QwtPointMapper::toPoints	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QwtSeriesData< QPointF > *	series,
		int	from,
		int	to
	)		const

Translate a series of points into a QPolygon.

WeedOutPoints & boundingRect().isValid() All points that are mapped to the same position will be one point. Points outside of the bounding rectangle are ignored.
WeedOutPoints & !boundingRect().isValid() All consecutive points that are mapped to the same position will one point
!WeedOutPoints & boundingRect().isValid() Points outside of the bounding rectangle are ignored.

Parameters

xMap	x map
yMap	y map
series	Series of points to be mapped
from	Index of the first point to be painted
to	Index of the last point to be painted

Returns: Translated polygon

◆ toPointsF()

QPolygonF QwtPointMapper::toPointsF	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QwtSeriesData< QPointF > *	series,
		int	from,
		int	to
	)		const

Translate a series into a QPolygonF.

WeedOutPoints & RoundPoints & boundingRect().isValid() All points that are mapped to the same position will be one point. Points outside of the bounding rectangle are ignored.
WeedOutPoints & RoundPoints & !boundingRect().isValid() All consecutive points that are mapped to the same position will one point
WeedOutPoints & !RoundPoints All consecutive points that are mapped to the same position will one point
!WeedOutPoints & boundingRect().isValid() Points outside of the bounding rectangle are ignored.

When RoundPoints is set all points are rounded to integers but returned as PolygonF - what only makes sense when the further processing of the values need a QPolygonF.

Parameters

xMap	x map
yMap	y map
series	Series of points to be mapped
from	Index of the first point to be painted
to	Index of the last point to be painted

Returns: Translated polygon

◆ toPolygon()

QPolygon QwtPointMapper::toPolygon	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QwtSeriesData< QPointF > *	series,
		int	from,
		int	to
	)		const

Translate a series of points into a QPolygon.

When the WeedOutPoints flag is enabled consecutive points, that are mapped to the same position will be one point.

Parameters

xMap	x map
yMap	y map
series	Series of points to be mapped
from	Index of the first point to be painted
to	Index of the last point to be painted

Returns: Translated polygon

◆ toPolygonF()

QPolygonF QwtPointMapper::toPolygonF	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QwtSeriesData< QPointF > *	series,
		int	from,
		int	to
	)		const

Translate a series of points into a QPolygonF.

When the WeedOutPoints flag is enabled consecutive points, that are mapped to the same position will be one point.

When RoundPoints is set all points are rounded to integers but returned as PolygonF - what only makes sense when the further processing of the values need a QPolygonF.

When RoundPoints & WeedOutIntermediatePoints is enabled an even more aggressive weeding algorithm is enabled.

Parameters

xMap	x map
yMap	y map
series	Series of points to be mapped
from	Index of the first point to be painted
to	Index of the last point to be painted

Returns: Translated polygon

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

/home/runner/work/QWT/QWT/src/qwt_point_mapper.h
/home/runner/work/QWT/QWT/src/qwt_point_mapper.cpp

Classes

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ TransformationFlag

Member Function Documentation

◆ boundingRect()

◆ flags()

◆ setBoundingRect()

◆ setFlag()

◆ setFlags()

◆ testFlag()

◆ toImage()

◆ toPoints()

◆ toPointsF()

◆ toPolygon()

◆ toPolygonF()