Qwt User's Guide: QwtLinearColorMap Class Reference

Qwt User's Guide 6.2.0

Public Types | Public Member Functions | List of all members
QwtLinearColorMap Class Reference

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

`#include <qwt_color_map.h>`

Inheritance diagram for QwtLinearColorMap:

## 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 override
virtual uint | colorIndex (int numColors, const QwtInterval &, double value) const override
| Map a value of a given interval into a color index. More...
Public Member Functions inherited from QwtColorMap
| QwtColorMap (Format=QwtColorMap::RGB)
virtual | ~QwtColorMap ()
| Destructor.
void | setFormat (Format)
QColor | color (const QwtInterval &, double value) const
virtual QVector< QRgb > | colorTable (int numColors) const
virtual QVector< QRgb > | colorTable256 () const

## Additional Inherited Members
Public Attributes inherited from QwtColorMap
Format | 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().

Definition at line 98 of file qwt_color_map.h.

## Member Enumeration Documentation

## ◆ Mode

enum QwtLinearColorMap::Mode

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.

Definition at line 105 of file qwt_color_map.h.

## Constructor & Destructor Documentation

## ◆ QwtLinearColorMap() [1/2]

QwtLinearColorMap::QwtLinearColorMap | ( | QwtColorMap::Format | format = `QwtColorMap::RGB` | ) |
| explicit

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

Definition at line 351 of file qwt_color_map.cpp.

## ◆ QwtLinearColorMap() [2/2]

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 for the color map

Definition at line 367 of file qwt_color_map.cpp.

## Member Function Documentation

## ◆ addColorStop()

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

Definition at line 433 of file qwt_color_map.cpp.

## ◆ color1()

QColor QwtLinearColorMap::color1 | ( |  | ) | const

Returns
  the first color of the color range

See also
  setColorInterval()

Definition at line 451 of file qwt_color_map.cpp.

## ◆ color2()

QColor QwtLinearColorMap::color2 | ( |  | ) | const

Returns
  the second color of the color range

See also
  setColorInterval()

Definition at line 460 of file qwt_color_map.cpp.

## ◆ colorIndex()

uint QwtLinearColorMap::colorIndex | ( | int | numColors,
|  | const QwtInterval & | interval,
|  | double | value
| ) |  | const
| overridevirtual

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

Parameters

  numColors | Size of the color table
  interval | Range for all values
  value | Value to map into a color index

Returns
  Index, between 0 and 255

Note
  NaN values are mapped to 0

Reimplemented from QwtColorMap.

Definition at line 494 of file qwt_color_map.cpp.

## ◆ colorStops()

QVector< double > QwtLinearColorMap::colorStops | ( |  | ) | const

Returns
  Positions of color stops in increasing order

Definition at line 442 of file qwt_color_map.cpp.

## ◆ mode()

QwtLinearColorMap::Mode QwtLinearColorMap::mode | ( |  | ) | const

Returns
  Mode of the color map

See also
  setMode()

Definition at line 400 of file qwt_color_map.cpp.

## ◆ rgb()

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

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

Returns
  RGB value for value

Implements QwtColorMap.

Definition at line 473 of file qwt_color_map.cpp.

## ◆ setColorInterval()

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()

Definition at line 415 of file qwt_color_map.cpp.

## ◆ setMode()

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()

Definition at line 391 of file qwt_color_map.cpp.