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

#include <qwt_point_mapper.h>

类
class	PrivateData

Public 类型
enum	TransformationFlag { RoundPoints = 0x01 , WeedOutPoints = 0x02 , WeedOutIntermediatePoints = 0x04 , PixelColumnReduce = 0x08 , MinMaxReduce = 0x10 }
	Flags affecting the transformation process 更多...

Public 成员函数
	QwtPointMapper ()
	Constructor

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

TransformationFlags	flags () const
	Get the flags affecting the transformation process

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

bool	testFlag (TransformationFlag) const
	Test if a flag is set

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

QRectF	boundingRect () const
	Get the bounding rectangle

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 (scattered points)

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

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

详细描述

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>.

成员枚举类型说明

◆ TransformationFlag

enum QwtPointMapper::TransformationFlag

Flags affecting the transformation process

参见: setFlag(), setFlags()

枚举值
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 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.
PixelColumnReduce	Pixel-column based downsampling Allocates a bin array indexed by pixel column and stores first/min/max/last Y per column. Output is at most 4 points per column. Requires a valid boundingRect() to determine the canvas width. Overrides WeedOutIntermediatePoints when both are set.
MinMaxReduce	MinMax bucket downsampling Divides the visible data into equal-count buckets and keeps the min-Y and max-Y point from each bucket. Target bucket count is derived from boundingRect() width. Overrides WeedOutIntermediatePoints when both are set.

构造及析构函数说明

◆ QwtPointMapper()

QwtPointMapper::QwtPointMapper ( )

Constructor

Creates a QwtPointMapper with default settings.

Destructor

Destroys the QwtPointMapper and frees all allocated resources.

成员函数说明

◆ boundingRect()

QRectF QwtPointMapper::boundingRect ( ) const

Get the bounding rectangle

返回: Bounding rectangle

参见: setBoundingRect()

◆ flags()

QwtPointMapper::TransformationFlags QwtPointMapper::flags ( ) const

Get the flags affecting the transformation process

返回: Flags affecting the transformation process

参见: 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.

参数

[in] rect Bounding rectangle

参见: boundingRect()

◆ setFlag()

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

Modify a flag affecting the transformation process

参数

[in]	flag	Flag type
[in]	on	Value

参见: testFlag(), setFlags()

◆ setFlags()

void QwtPointMapper::setFlags ( TransformationFlags flags )

Set the flags affecting the transformation process

参数

[in] flags Flags

参见: flags(), setFlag()

◆ testFlag()

bool QwtPointMapper::testFlag ( TransformationFlag flag ) const

Test if a flag is set

参数

[in] flag Flag type

返回: True when the flag is set

参见: 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

参数

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

返回: 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 (scattered points)

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.

参数

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

返回: 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 (scattered points)

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.

参数

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

返回: 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.

参数

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

返回: 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.

参数

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

返回: Translated polygon

该类的文档由以下文件生成:

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

类

Public 类型

Public 成员函数

详细描述

成员枚举类型说明

◆ TransformationFlag

构造及析构函数说明

◆ QwtPointMapper()

成员函数说明

◆ boundingRect()

◆ flags()

◆ setBoundingRect()

◆ setFlag()

◆ setFlags()

◆ testFlag()

◆ toImage()

◆ toPoints()

◆ toPointsF()

◆ toPolygon()

◆ toPolygonF()