QwtColorMap Class Reference

Inheritance diagram for QwtColorMap:

Inheritance graph
[legend]

List of all members.


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:

See also:
QwtPlotSpectrogram, QwtScaleWidget

Definition at line 44 of file qwt_color_map.h.


Public Types

enum  Format {
  RGB,
  Indexed
}

Public Member Functions

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

Member Enumeration Documentation

  • 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()

Definition at line 57 of file qwt_color_map.h.


Constructor & Destructor Documentation

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

Constructor.

Definition at line 164 of file qwt_color_map.cpp.

QwtColorMap::~QwtColorMap (  )  [virtual]

Destructor.

Definition at line 170 of file qwt_color_map.cpp.


Member Function Documentation

QwtColorMap::Format QwtColorMap::format (  )  const [inline]

Returns:
Intended format of the color map
See also:
Format

Definition at line 216 of file qwt_color_map.h.

virtual QwtColorMap* QwtColorMap::copy (  )  const [pure virtual]

Clone the color map.

Implemented in QwtLinearColorMap, and QwtAlphaColorMap.

Referenced by QwtPlotSpectrogram::setColorMap().

virtual QRgb QwtColorMap::rgb ( const QwtDoubleInterval interval,
double  value 
) 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 QwtLinearColorMap, and QwtAlphaColorMap.

Referenced by color(), and colorTable().

virtual unsigned char QwtColorMap::colorIndex ( const QwtDoubleInterval interval,
double  value 
) 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.

Referenced by color().

QColor QwtColorMap::color ( const QwtDoubleInterval 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().

Definition at line 198 of file qwt_color_map.h.

References colorIndex(), colorTable(), and rgb().

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

Definition at line 183 of file qwt_color_map.cpp.

References QwtDoubleInterval::isValid(), QwtDoubleInterval::minValue(), rgb(), and QwtDoubleInterval::width().

Referenced by color().


Generated on Sat May 31 11:11:10 2008 for Qwt User's Guide by  doxygen 1.5.5