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QwtColorMap

QwtColorMap

Section: C Library Functions (3) Updated: 22 Mar 2009
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NAME

QwtColorMap - QwtColorMap is used to map values into colors.

 

SYNOPSIS


#include <qwt_color_map.h>

Inherited by QwtAlphaColorMap, and QwtLinearColorMap.

 

Public Types


enum Format { RGB, Indexed }
 

Public Member Functions


QwtColorMap (Format=QwtColorMap::RGB)

virtual ~QwtColorMap ()

Format format () const

virtual QwtColorMap * copy () const =0

virtual QRgb rgb (const QwtDoubleInterval &interval, double value) const =0

virtual unsigned char colorIndex (const QwtDoubleInterval &interval, double value) const =0

QColor color (const QwtDoubleInterval &, double value) const

virtual QVector< QRgb > colorTable (const QwtDoubleInterval &) const
 

Detailed Description

QwtColorMap is used to map values into colors.

For displaying 3D data on a 2D plane the 3rd dimension is often displayed using colors, like f.e in a spectrogram.

Each color map is optimized to return colors for only one of the following image formats:

QImage::Format_Indexed8

QImage::Format_ARGB32

See also:

QwtPlotSpectrogram, QwtScaleWidget

 

Member Enumeration Documentation

 

enum QwtColorMap::Format

RGB

 The map is intended to map into QRgb values.
Indexed

 The map is intended to map into 8 bit values, that are indices into the color table.

See also:

rgb(), colorIndex(), colorTable()

 

Constructor & Destructor Documentation

 

QwtColorMap::QwtColorMap (Format format = QwtColorMap::RGB)

Constructor.

 

QwtColorMap::~QwtColorMap () [virtual]

Destructor.

 

Member Function Documentation

 

QColor QwtColorMap::color (const QwtDoubleInterval & interval, double value) const [inline]

Map a value into a color

Parameters:

interval Valid interval for values
value Value

Returns:

Color corresponding to value

Warning:

This method is slow for Indexed color maps. If it is necessary to map many values, its better to get the color table once and find the color using colorIndex().

 

virtual unsigned char QwtColorMap::colorIndex (const QwtDoubleInterval & interval, double value) const [pure virtual]

Map a value of a given interval into a color index

Parameters:

interval Range for the values
value Value

Returns:

color index, corresponding to value

Implemented in QwtLinearColorMap.  

QwtColorTable QwtColorMap::colorTable (const QwtDoubleInterval & interval) const [virtual]

Build and return a color map of 256 colors

The color table is needed for rendering indexed images in combination with using colorIndex().

Parameters:

interval Range for the values

Returns:

A color table, that can be used for a QImage

 

virtual QwtColorMap* QwtColorMap::copy () const [pure virtual]

Clone the color map.

Implemented in QwtLinearColorMap, and QwtAlphaColorMap.  

QwtColorMap::Format QwtColorMap::format () const [inline]

Returns:

Intended format of the color map

See also:

Format

 

virtual QRgb QwtColorMap::rgb (const QwtDoubleInterval & interval, double value) const [pure virtual]

Map a value of a given interval into a rgb value.

Parameters:

interval Range for the values
value Value

Returns:

rgb value, corresponding to value

Implemented in QwtLinearColorMap, and QwtAlphaColorMap.

 

Author

Generated automatically by Doxygen for Qwt User's Guide from the source code.


 

Index

NAME
SYNOPSIS
Public Types
Public Member Functions
Detailed Description
Member Enumeration Documentation
enum QwtColorMap::Format
Constructor & Destructor Documentation
QwtColorMap::QwtColorMap (Format format = QwtColorMap::RGB)
QwtColorMap::~QwtColorMap () [virtual]
Member Function Documentation
QColor QwtColorMap::color (const QwtDoubleInterval & interval, double value) const [inline]
virtual unsigned char QwtColorMap::colorIndex (const QwtDoubleInterval & interval, double value) const [pure virtual]
QwtColorTable QwtColorMap::colorTable (const QwtDoubleInterval & interval) const [virtual]
virtual QwtColorMap* QwtColorMap::copy () const [pure virtual]
QwtColorMap::Format QwtColorMap::format () const [inline]
virtual QRgb QwtColorMap::rgb (const QwtDoubleInterval & interval, double value) const [pure virtual]
Author

This document was created by man2html, using the manual pages.
Time: 21:53:51 GMT, April 16, 2011