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QwtPointMapper(3) Qwt User's Guide QwtPointMapper(3)

NAME

QwtPointMapper - A helper class for translating a series of points.

SYNOPSIS

#include <qwt_point_mapper.h>

Public Types


enum TransformationFlag { RoundPoints = 0x01, WeedOutPoints = 0x02 }
Flags affecting the transformation process. typedef QFlags< TransformationFlag > TransformationFlags
Flags affecting the transformation process.

Public Member Functions


QwtPointMapper ()
Constructor. ~QwtPointMapper ()
Destructor. void setFlags (TransformationFlags)
TransformationFlags flags () const
void setFlag (TransformationFlag, bool on=true)
bool testFlag (TransformationFlag) const
void setBoundingRect (const QRectF &)
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 Typedef Documentation

typedef QFlags<TransformationFlag> QwtPointMapper::TransformationFlags

Flags affecting the transformation process.

See also:

setFlag(), setFlags()

Member Enumeration Documentation

enum QwtPointMapper::TransformationFlag

Flags affecting the transformation process.

See also:

setFlag(), setFlags()

Enumerator

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

Member Function Documentation

QRectF QwtPointMapper::boundingRect () const

Returns:

Bounding rectangle

See also:

setBoundingRect()

QwtPointMapper::TransformationFlags QwtPointMapper::flags () const

Returns:

Flags affecting the transformation process

See also:

setFlags(), setFlag()

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()

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()

void QwtPointMapper::setFlags (TransformationFlags flags)

Set the flags affecting the transformation process

Parameters:

flags Flags

See also:

flags(), setFlag()

bool QwtPointMapper::testFlag (TransformationFlag flag) const

Returns:

True, when the flag is set

Parameters:

flag Flag type

See also:

setFlag(), setFlags()

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

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

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

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

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.

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

Author

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Wed Jan 2 2019 Version 6.1.4