Package org.openhab.core.util

Class ColorUtil

java.lang.Object

org.openhab.core.util.ColorUtil

@NonNullByDefault
public class ColorUtil
extends Object

The ColorUtil is responsible for converting different color formats. The implementation of HSB/CIE conversion is based work from Erik Baauw for the Homebridge project.

Author:

Jan N. Klug - Initial contribution, Holger Friedrich - Transfer RGB color conversion from HSBType, improve RGB conversion, restructuring, Chris Jackson - Added fromRGB (moved from HSBType), Andrew Fiddian-Green - Extensive revamp to fix bugs and improve accuracy

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	ColorUtil.Gamut	Color gamut
static class	ColorUtil.Point	Class for points in the CIE xy color space

Field Summary

Fields

Modifier and Type	Field	Description
static final ColorUtil.Gamut	DEFAULT_GAMUT

Method Summary

Modifier and Type	Method	Description
static int[]	hsbToRgb(HSBType hsb)	Transform HSV based HSBType to sRGB.
static PercentType[]	hsbToRgbPercent(HSBType hsb)	Transform HSV based HSBType to sRGB.
static int[]	hsbToRgbw(HSBType hsb)	Transform HSV based HSBType to sRGB.
static PercentType[]	hsbToRgbwPercent(HSBType hsb)	Transform HSV based HSBType to RGBW.
static int	hsbTosRgb(HSBType hsb)	Transform HSV based HSBType to the RGB value representing the color in the default sRGB color model.
static double[]	hsbToXY(HSBType hsb)	Transform HSV based HSBType to CIE 1931 xy format.
static double[]	hsbToXY(HSBType hsb, ColorUtil.Gamut gamut)	Transform HSV based HSBType to CIE 1931 xy format.
static HSBType	rgbToHsb(int[] rgbw)	Transform sRGB color format to HSV based HSBType.
static HSBType	rgbToHsb(PercentType[] rgbw)	Transform sRGB color format to HSV based HSBType.
static HSBType	xyToHsb(double[] xy)	Transform CIE 1931 xy format to HSV based HSBType.
static HSBType	xyToHsb(double[] xyY, ColorUtil.Gamut gamut)	Transform CIE 1931 xy format to HSV based HSBType.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT_GAMUT

public static final ColorUtil.Gamut DEFAULT_GAMUT

Method Details

hsbToRgb

public static int[] hsbToRgb(HSBType hsb)

Transform HSV based HSBType to sRGB. This function does rounding to integer valued components. It is the preferred way of doing HSB to RGB conversion. See also: hsbToRgbPercent(HSBType), hsbToRgbw(HSBType), hsbTosRgb(HSBType)

Parameters:

hsb - an HSBType value.

Returns:

array of three int with the RGB values in the range 0 to 255.

hsbToRgbw

public static int[] hsbToRgbw(HSBType hsb)

Transform HSV based HSBType to sRGB. This function does rounding to integer valued components. It is the preferred way of doing HSB to RGBW conversion. See also: hsbToRgbPercent(HSBType), hsbToRgbwPercent(HSBType), hsbTosRgb(HSBType)

Parameters:

hsb - an HSBType value.

Returns:

array of four int with the RGBW values in the range 0 to 255.

hsbToRgbPercent

public static PercentType[] hsbToRgbPercent(HSBType hsb)

Transform HSV based HSBType to sRGB. This function does not round the components. For conversion to integer values in the range 0 to 255 use hsbToRgb(HSBType). See also: hsbToRgb(HSBType), hsbTosRgb(HSBType), hsbToRgbwPercent(HSBType)

Parameters:

hsb - an HSBType value.

Returns:

array of three PercentType with the RGB values in the range 0 to 100 percent.

hsbToRgbwPercent

public static PercentType[] hsbToRgbwPercent(HSBType hsb)

Transform HSV based HSBType to RGBW. See Converting RGB to RGBW. This function does not round the components. For conversion to integer values in the range 0 to 255 use hsbToRgb(HSBType). See also: hsbToRgb(HSBType), hsbTosRgb(HSBType), hsbToRgbPercent(HSBType)

Parameters:

hsb - an HSBType value.

Returns:

array of four PercentType with the RGBW values in the range 0 to 100 percent.

hsbTosRgb

public static int hsbTosRgb(HSBType hsb)

Transform HSV based HSBType to the RGB value representing the color in the default sRGB color model. (Bits 24-31 are alpha, 16-23 are red, 8-15 are green, 0-7 are blue). See also: hsbToRgb(HSBType), hsbToRgbPercent(HSBType)

Parameters:

hsb - an HSBType value.

Returns:

the RGB value of the color in the default sRGB color model.

hsbToXY

public static double[] hsbToXY(HSBType hsb)

Transform HSV based HSBType to CIE 1931 xy format. See Hue developerportal.

Parameters:

hsb - an HSBType value.

Returns:

array of three double with the closest matching CIE 1931 x,y,Y in the range 0.0000 to 1.0000

hsbToXY

public static double[] hsbToXY(HSBType hsb,
 ColorUtil.Gamut gamut)

Transform HSV based HSBType to CIE 1931 xy format. See Hue developer portal.

Parameters:

hsb - an HSBType value.

gamut - the color Gamut supported by the light.

Returns:

array of three or four double with the closest matching CIE 1931 x,y,Y in the range 0.0000 to 1.0000 - plus an optional extra empty element to flag if the xyY result has been forced inside the given Gamut.

rgbToHsb

public static HSBType rgbToHsb(int[] rgbw)
                        throws IllegalArgumentException

Transform sRGB color format to HSV based HSBType.

Parameters:

rgbw - array of three or four int with the RGB(W) values in the range 0 to 255.

Returns:

the corresponding HSBType.

Throws:

IllegalArgumentException - when input array has wrong size or exceeds allowed value range.

rgbToHsb

public static HSBType rgbToHsb(PercentType[] rgbw)
                        throws IllegalArgumentException

Transform sRGB color format to HSV based HSBType.

Parameters:

rgbw - array of three or four PercentType with the RGB(W) values in the range 0 to 100 percent.

Returns:

the corresponding HSBType.

Throws:

IllegalArgumentException - when input array has wrong size or exceeds allowed value range.

xyToHsb

public static HSBType xyToHsb(double[] xy)
                       throws IllegalArgumentException

Transform CIE 1931 xy format to HSV based HSBType. See Hue developer portal.

Parameters:

xy - array of double with CIE 1931 x,y[,Y] in the range 0.0000 to 1.0000 Y value is optional.

Returns:

the corresponding HSBType.

Throws:

IllegalArgumentException - when input array has wrong size or exceeds allowed value range.

xyToHsb

public static HSBType xyToHsb(double[] xyY,
 ColorUtil.Gamut gamut)
                       throws IllegalArgumentException

Transform CIE 1931 xy format to HSV based HSBType. See Hue developer portal.

Parameters:

xyY - array of double with CIE 1931 x,y[,Y] in the range 0.0000 to 1.0000 Y value is optional.

gamut - the color Gamut supported by the light.

Returns:

the corresponding HSBType.

Throws:

IllegalArgumentException - when input array has wrong size or exceeds allowed value range