QwtColorMap Class Reference
QwtColorMap is used to map values into colors. More...
#include <qwt_color_map.h>
Public Types | |
| enum | Format { RGB, Indexed } |
Public Member Functions | |
| QwtColorMap (Format=QwtColorMap::RGB) | |
| virtual | ~QwtColorMap () |
| Format | format () const |
| virtual QwtColorMap * | copy () 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 |
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
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()
Constructor & Destructor Documentation
| QwtColorMap::QwtColorMap | ( | Format | format = QwtColorMap::RGB |
) |
Constructor.
| QwtColorMap::~QwtColorMap | ( | ) | [virtual] |
Destructor.
Member Function Documentation
| 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().
| 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.
| 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
| virtual QwtColorMap* QwtColorMap::copy | ( | ) | const [pure virtual] |
Clone the color map.
Implemented in QwtLinearColorMap, and QwtAlphaColorMap.
| QwtColorMap::Format QwtColorMap::format | ( | ) | const [inline] |
- Returns:
- Intended format of the color map
- See also:
- Format
| 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.
Generated on Wed Sep 2 18:37:23 2009 for Qwt User's Guide by
1.6.1