Qwt User's Guide
QwtPointMapper Class Reference

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

#include <qwt_point_mapper.h>

Public Types

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

Flags affecting the transformation process.

See also:
setFlag(), setFlags()

Member Enumeration Documentation

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.


Member Function Documentation

QRectF QwtPointMapper::boundingRect ( ) const
Returns:
Bounding rectangle
See also:
setBoundingRect()
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:
rectBounding rectangle
See also:
boundingRect()
void QwtPointMapper::setFlag ( TransformationFlag  flag,
bool  on = true 
)

Modify a flag affecting the transformation process

Parameters:
flagFlag type
onValue
See also:
flag(), setFlags()

Set the flags affecting the transformation process

Parameters:
flagsFlags
See also:
flags(), setFlag()
Returns:
True, when the flag is set
Parameters:
flagFlag 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:
xMapx map
yMapy map
seriesSeries of points to be mapped
fromIndex of the first point to be painted
toIndex of the last point to be painted
penPen used for drawing a point of the image, where a point is mapped to
antialiasedTrue, when the dots should be displayed antialiased
numThreadsNumber 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:
xMapx map
yMapy map
seriesSeries of points to be mapped
fromIndex of the first point to be painted
toIndex 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:
xMapx map
yMapy map
seriesSeries of points to be mapped
fromIndex of the first point to be painted
toIndex 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:
xMapx map
yMapy map
seriesSeries of points to be mapped
fromIndex of the first point to be painted
toIndex 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:
xMapx map
yMapy map
seriesSeries of points to be mapped
fromIndex of the first point to be painted
toIndex of the last point to be painted
Returns:
Translated polygon

List of all members.

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