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 }

QwtColorMap (Format=QwtColorMap::RGB)
Constructor. virtual ~QwtColorMap ()
Destructor. Format format () const
virtual QRgb rgb (const QwtInterval &interval, double value) const =0
virtual unsigned char colorIndex (const QwtInterval &interval, double value) const =0
QColor color (const QwtInterval &, double value) const
virtual QVector< QRgb > colorTable (const QwtInterval &) 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

Format for color mapping

See also:

rgb(), colorIndex(), colorTable()

Enumerator

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

Member Function Documentation

QColor QwtColorMap::color (const QwtInterval & 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().