QwtLinearColorMap Class Reference

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

#include <qwt_color_map.h>

Inheritance diagram for QwtLinearColorMap:

Inheritance graph
[legend]

List of all members.

Public Types

enum  Format {
  RGB,
  Indexed
}
enum  Mode {
  FixedColors,
  ScaledColors
}

Public Member Functions

void addColorStop (double value, const QColor &)
QColor color (const QwtInterval &, double value) const
QColor color1 () const
QColor color2 () const
virtual unsigned char colorIndex (const QwtInterval &, double value) const
QVector< double > colorStops () const
virtual QVector< QRgb > colorTable (const QwtInterval &) const
Format format () const
Mode mode () const
 QwtLinearColorMap (const QColor &from, const QColor &to, QwtColorMap::Format=QwtColorMap::RGB)
 QwtLinearColorMap (QwtColorMap::Format=QwtColorMap::RGB)
virtual QRgb rgb (const QwtInterval &, 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 according to mode().


Member Enumeration Documentation

enum QwtColorMap::Format [inherited]

Format for color mapping

See also:
rgb(), colorIndex(), colorTable()
Enumerator:
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.

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:
format Preferred 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:
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 (  )  [virtual]

Destructor.


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:
value Value between [0.0, 1.0]
color Color stop

QColor QwtColorMap::color ( const QwtInterval interval,
double  value 
) 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 QwtInterval interval,
double  value 
) 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.

QVector< double > QwtLinearColorMap::colorStops (  )  const

Return all positions of color stops in increasing order

QVector< QRgb > QwtColorMap::colorTable ( const QwtInterval 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::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()

QRgb QwtLinearColorMap::rgb ( const QwtInterval interval,
double  value 
) 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 ( 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()


Generated on Wed Jan 11 15:23:01 2012 for Qwt User's Guide by  doxygen 1.5.9