.TH "QwtColorMap" 3 "Wed Jan 2 2019" "Version 6.1.4" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtColorMap \- \fBQwtColorMap\fP is used to map values into colors\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_color_map\&.h>\fP
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Inherited by \fBQwtAlphaColorMap\fP, and \fBQwtLinearColorMap\fP\&.
.SS "Public Types"

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.RI "enum \fBFormat\fP { \fBRGB\fP, \fBIndexed\fP }"
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.SS "Public Member Functions"

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.RI "\fBQwtColorMap\fP (\fBFormat\fP=\fBQwtColorMap::RGB\fP)"
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.RI "Constructor\&. "
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.RI "virtual \fB~QwtColorMap\fP ()"
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.RI "Destructor\&. "
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.RI "\fBFormat\fP \fBformat\fP () const"
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.RI "virtual QRgb \fBrgb\fP (const \fBQwtInterval\fP &interval, double value) const =0"
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.RI "virtual unsigned char \fBcolorIndex\fP (const \fBQwtInterval\fP &interval, double value) const =0"
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.RI "QColor \fBcolor\fP (const \fBQwtInterval\fP &, double value) const"
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.RI "virtual QVector< QRgb > \fBcolorTable\fP (const \fBQwtInterval\fP &) const"
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.SH "Detailed Description"
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\fBQwtColorMap\fP 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\&.
.PP
Each color map is optimized to return colors for only one of the following image formats:
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.IP "\(bu" 2
QImage::Format_Indexed8
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.IP "\(bu" 2
QImage::Format_ARGB32
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\fBSee also:\fP
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\fBQwtPlotSpectrogram\fP, \fBQwtScaleWidget\fP 
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.SH "Member Enumeration Documentation"
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.SS "enum \fBQwtColorMap::Format\fP"
Format for color mapping 
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\fBSee also:\fP
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\fBrgb()\fP, \fBcolorIndex()\fP, \fBcolorTable()\fP 
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\fBEnumerator\fP
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.TP
\fB\fIRGB \fP\fP
The map is intended to map into RGB values\&. 
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\fB\fIIndexed \fP\fP
The map is intended to map into 8 bit values, that are indices into the color table\&. 
.SH "Member Function Documentation"
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.SS "QColor QwtColorMap::color (const \fBQwtInterval\fP & interval, double value) const\fC [inline]\fP"
Map a value into a color
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\fBParameters:\fP
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\fIinterval\fP Valid interval for values 
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\fIvalue\fP Value
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\fBReturns:\fP
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Color corresponding to value
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\fBWarning:\fP
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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 \fBcolorIndex()\fP\&. 
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.SS "virtual unsigned char QwtColorMap::colorIndex (const \fBQwtInterval\fP & interval, double value) const\fC [pure virtual]\fP"
Map a value of a given interval into a color index
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\fBParameters:\fP
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\fIinterval\fP Range for the values 
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\fIvalue\fP Value 
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\fBReturns:\fP
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color index, corresponding to value 
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Implemented in \fBQwtLinearColorMap\fP\&.
.SS "QVector< QRgb > QwtColorMap::colorTable (const \fBQwtInterval\fP & interval) const\fC [virtual]\fP"
Build and return a color map of 256 colors
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The color table is needed for rendering indexed images in combination with using \fBcolorIndex()\fP\&.
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\fBParameters:\fP
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\fIinterval\fP Range for the values 
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\fBReturns:\fP
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A color table, that can be used for a QImage 
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.SS "\fBQwtColorMap::Format\fP QwtColorMap::format () const\fC [inline]\fP"

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\fBReturns:\fP
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Intended format of the color map 
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\fBSee also:\fP
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\fBFormat\fP 
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.SS "virtual QRgb QwtColorMap::rgb (const \fBQwtInterval\fP & interval, double value) const\fC [pure virtual]\fP"
Map a value of a given interval into a RGB value\&.
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\fBParameters:\fP
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\fIinterval\fP Range for the values 
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\fIvalue\fP Value 
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\fBReturns:\fP
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RGB value, corresponding to value 
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.PP
Implemented in \fBQwtAlphaColorMap\fP, and \fBQwtLinearColorMap\fP\&.

.SH "Author"
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Generated automatically by Doxygen for Qwt User's Guide from the source code\&.