QwtColorMap(3) Qwt User's Guide QwtColorMap(3)NAMEQwtColorMap-
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 ()
QColor color (const QwtDoubleInterval &, double value) const
virtual unsigned char colorIndex (const QwtDoubleInterval &interval,
double value) const =0
virtual QVector< QRgb > colorTable (const QwtDoubleInterval &) const
virtual QwtColorMap * copy () const =0
Format format () const
virtual QRgb rgb (const QwtDoubleInterval &interval, double value)
const =0
Detailed DescriptionQwtColorMap 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()Member Function Documentation
QColor QwtColorMap::color (const QwtDoubleInterval &interval, doublevalue)
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, doublevalue) 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
QwtColorMap::Format QwtColorMap::format () const [inline]
Returns:
Intended format of the color map
See also:
Format
virtual QRgb QwtColorMap::rgb (const QwtDoubleInterval &interval,
doublevalue) 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 QwtAlphaColorMap, and QwtLinearColorMap.
Author
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Version 5.2.3 Tue Nov 20 2012 QwtColorMap(3)
