QwtColorMap - Man Page

QwtColorMap is used to map values into colors.

Synopsis

#include <qwt_color_map.h>

Inherited by QwtAlphaColorMap, QwtHueColorMap, QwtLinearColorMap, and QwtSaturationValueColorMap.

Public Types

enum Format { RGB, Indexed }

QwtColorMap (Format=QwtColorMap::RGB)
virtual ~QwtColorMap ()
Destructor.
void setFormat (Format)
virtual QRgb rgb (const QwtInterval &interval, double value) const =0
virtual uint colorIndex (int numColors, const QwtInterval &interval, double value) const
Map a value of a given interval into a color index.
QColor color (const QwtInterval &, double value) const
virtual QVector< QRgb > colorTable (int numColors) const
virtual QVector< QRgb > colorTable256 () const

Public Attributes

Format 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

Definition at line 37 of file qwt_color_map.h.

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: Map values into 8 bit values, that are used as indexes into the color table.

Indexed color maps are used to generate QImage::Format_Indexed8 images. The calculation of the color index is usually faster and the resulting image has a lower memory footprint.

See also: colorIndex(), colorTable()

Definition at line 45 of file qwt_color_map.h.

Constructor & Destructor Documentation

QwtColorMap::QwtColorMap (Format format = QwtColorMap::RGB) [explicit]

Constructor

Parameters: format Format of the color map

Definition at line 249 of file qwt_color_map.cpp.

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

Definition at line 248 of file qwt_color_map.h.

uint QwtColorMap::colorIndex (int numColors, const QwtInterval & interval, double value) const [virtual]

Map a value of a given interval into a color index.

Parameters: numColors Number of colors
interval Range for all values
value Value to map into a color index
Returns: Index, between 0 and numColors - 1, or -1 for an invalid value

Reimplemented in QwtLinearColorMap.

Definition at line 278 of file qwt_color_map.cpp.