Qwt User's Guide  6.1.0
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QwtLinearColorMap Class Reference

QwtLinearColorMap builds a color map from color stops. More...

#include <qwt_color_map.h>

Inheritance diagram for QwtLinearColorMap:
Inheritance graph
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Public Types

enum  Mode { FixedColors, ScaledColors }
 
- Public Types inherited from QwtColorMap
enum  Format { RGB, Indexed }
 

Public Member Functions

 QwtLinearColorMap (QwtColorMap::Format=QwtColorMap::RGB)
 
 QwtLinearColorMap (const QColor &from, const QColor &to, QwtColorMap::Format=QwtColorMap::RGB)
 
virtual ~QwtLinearColorMap ()
 Destructor.
 
void setMode (Mode)
 Set the mode of the color map. More...
 
Mode mode () const
 
void setColorInterval (const QColor &color1, const QColor &color2)
 
void addColorStop (double value, const QColor &)
 
QVector< double > colorStops () const
 
QColor color1 () const
 
QColor color2 () const
 
virtual QRgb rgb (const QwtInterval &, double value) const
 
virtual unsigned char colorIndex (const QwtInterval &, double value) const
 Map a value of a given interval into a color index. More...
 
- Public Member Functions inherited from QwtColorMap
 QwtColorMap (Format=QwtColorMap::RGB)
 Constructor.
 
virtual ~QwtColorMap ()
 Destructor.
 
Format format () const
 
QColor color (const QwtInterval &, double value) const
 
virtual QVector< QRgb > colorTable (const QwtInterval &) const
 

Detailed Description

QwtLinearColorMap builds a color map from color stops.

A color stop is a color at a specific position. The valid range for the positions is [0.0, 1.0]. When mapping a value into a color it is translated into this interval according to mode().

Member Enumeration Documentation

Mode of color map

See Also
setMode(), mode()
Enumerator
FixedColors 

Return the color from the next lower color stop.

ScaledColors 

Interpolating the colors of the adjacent stops.

Constructor & Destructor Documentation

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

Build a color map with two stops at 0.0 and 1.0. The color at 0.0 is Qt::blue, at 1.0 it is Qt::yellow.

Parameters
formatPreferred format of the color map
QwtLinearColorMap::QwtLinearColorMap ( const QColor &  color1,
const QColor &  color2,
QwtColorMap::Format  format = QwtColorMap::RGB 
)

Build a color map with two stops at 0.0 and 1.0.

Parameters
color1Color used for the minimum value of the value interval
color2Color used for the maximum value of the value interval
formatPreferred format for the color map

Member Function Documentation

void QwtLinearColorMap::addColorStop ( double  value,
const QColor &  color 
)

Add a color stop

The value has to be in the range [0.0, 1.0]. F.e. a stop at position 17.0 for a range [10.0,20.0] must be passed as: (17.0 - 10.0) / (20.0 - 10.0)

Parameters
valueValue between [0.0, 1.0]
colorColor stop
QColor QwtLinearColorMap::color1 ( ) const
Returns
the first color of the color range
See Also
setColorInterval()
QColor QwtLinearColorMap::color2 ( ) const
Returns
the second color of the color range
See Also
setColorInterval()
unsigned char QwtLinearColorMap::colorIndex ( const QwtInterval interval,
double  value 
) const
virtual

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

Parameters
intervalRange for all values
valueValue to map into a color index
Returns
Index, between 0 and 255

Implements QwtColorMap.

QVector< double > QwtLinearColorMap::colorStops ( ) const
Returns
Positions of color stops in increasing order
QwtLinearColorMap::Mode QwtLinearColorMap::mode ( ) const
Returns
Mode of the color map
See Also
setMode()
QRgb QwtLinearColorMap::rgb ( const QwtInterval interval,
double  value 
) const
virtual

Map a value of a given interval into a RGB value

Parameters
intervalRange for all values
valueValue to map into a RGB value
Returns
RGB value for value

Implements QwtColorMap.

void QwtLinearColorMap::setColorInterval ( const QColor &  color1,
const QColor &  color2 
)

Set the color range

Add stops at 0.0 and 1.0.

Parameters
color1Color used for the minimum value of the value interval
color2Color used for the maximum value of the value interval
See Also
color1(), color2()
void QwtLinearColorMap::setMode ( Mode  mode)

Set the mode of the color map.

FixedColors means the color is calculated from the next lower color stop. ScaledColors means the color is calculated by interpolating the colors of the adjacent stops.

See Also
mode()