QwtLinearColorMap Class Reference

#include <qwt_color_map.h>

Inherits QwtColorMap.

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 (QwtColorMap::Format=QwtColorMap::RGB)
	QwtLinearColorMap (const QColor &from, const QColor &to, 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().

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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.

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.

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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()