QwtLinearColorMap man page
QwtLinearColorMap —
QwtLinearColorMap builds a color map from color stops.
Synopsis
#include <qwt_color_map.h>
Inherits QwtColorMap.
Public Types
enum Format { RGB, Indexed }
enum Mode { FixedColors, ScaledColors }
Public Member Functions
void addColorStop (double value, const QColor &)
QColor color (const QwtDoubleInterval &, double value) const
QColor color1 () const
QColor color2 () const
virtual unsigned char colorIndex (const QwtDoubleInterval &, double value) const
QwtArray< double > colorStops () const
virtual QVector< QRgb > colorTable (const QwtDoubleInterval &) const
virtual QwtColorMap * copy () const
Format format () const
Mode mode () const
QwtLinearColorMap & operator= (const QwtLinearColorMap &)
QwtLinearColorMap (const QColor &from, const QColor &to, QwtColorMap::Format=QwtColorMap::RGB)
QwtLinearColorMap (QwtColorMap::Format=QwtColorMap::RGB)
QwtLinearColorMap (const QwtLinearColorMap &)
virtual QRgb rgb (const QwtDoubleInterval &, double value) const
void setColorInterval (const QColor &color1, const QColor &color2)
void setMode (Mode)
virtual ~QwtLinearColorMap ()
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. If mode() == FixedColors the color is calculated from the next lower color stop. If mode() == ScaledColors the color is calculated by interpolating the colors of the adjacent stops.
Member Enumeration Documentation
enum QwtColorMap::Format [inherited] .IP · 2
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()
enum QwtLinearColorMap::Mode Mode of color map
See also:
setMode(), mode()
Constructor & Destructor Documentation
QwtLinearColorMap::QwtLinearColorMap (QwtColorMap::Formatformat = 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:
format Preferred format of the color map
QwtLinearColorMap::QwtLinearColorMap (const QColor &color1, const QColor &color2, QwtColorMap::Formatformat = QwtColorMap::RGB) Build a color map with two stops at 0.0 and 1.0.
- Parameters:
color1 Color used for the minimum value of the value interval
color2 Color used for the maximum value of the value interval
format Preferred format of the coor map
QwtLinearColorMap::QwtLinearColorMap (const QwtLinearColorMap &other)
Copy constructor.
QwtLinearColorMap::~QwtLinearColorMap () [virtual]
Destructor.
Member Function Documentation
void QwtLinearColorMap::addColorStop (doublevalue, 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:
value Value between [0.0, 1.0]
color Color stop
QColor QwtColorMap::color (const QwtDoubleInterval &interval, doublevalue) const [inline, inherited] 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().
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 QwtDoubleInterval &interval, doublevalue) const [virtual] Map a value of a given interval into a color index, between 0 and 255
- Parameters:
interval Range for all values
value Value to map into a color index
Implements QwtColorMap.
QwtArray< double > QwtLinearColorMap::colorStops () const Return all positions of color stops in increasing order
QwtColorTable QwtColorMap::colorTable (const QwtDoubleInterval &interval) const [virtual, inherited] 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 * QwtLinearColorMap::copy () const [virtual]
Clone the color map.
Implements QwtColorMap.
QwtColorMap::Format QwtColorMap::format () const [inline, inherited] Returns
Intended format of the color map
See also:
Format
QwtLinearColorMap::Mode QwtLinearColorMap::mode () const Returns
Mode of the color map
See also:
setMode()
QwtLinearColorMap & QwtLinearColorMap::operator= (const QwtLinearColorMap &other)
Assignment operator.
QRgb QwtLinearColorMap::rgb (const QwtDoubleInterval &interval, doublevalue) const [virtual] Map a value of a given interval into a rgb value
- Parameters:
interval Range for all values
value Value to map into a rgb 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:
color1 Color used for the minimum value of the value interval
color2 Color used for the maximum value of the value interval- See also:
color1(), color2()
void QwtLinearColorMap::setMode (Modemode)
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()
Author
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