org.jhotdraw.color

Class CIELABColorSpace

java.lang.Object

java.awt.color.ColorSpace

org.jhotdraw.color.CIELABColorSpace

All Implemented Interfaces:

java.io.Serializable, NamedColorSpace

public class CIELABColorSpace
extends java.awt.color.ColorSpace
implements NamedColorSpace

The 1976 CIE L*a*b* color space (CIELAB).

The L* coordinate of an object is the lightness intensity as measured on a scale from 0 to 100, where 0 represents black and 100 represents white.

The a* coordinate of an object represents the position of the object’s color on a pure green and pure red scale, where -127 represents pure green and +127 represents pure red.

The b* coordinate represents the position of the object’s color on a pure blue and pure yellow scale, where -127 represents pure blue and +127 represents pure yellow.

The distance that can be calculated between two colors, is directly proportional to the difference between the two colors as perceived by the human eye.

The above description has been derived from http://www.optelvision.com/documents/optel-vision-s-explanation-on-cielab-color-space.pdf

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CIELABColorSpace.OutsideGamutHandling

Field Summary

Fields inherited from class java.awt.color.ColorSpace

CS_CIEXYZ, CS_GRAY, CS_LINEAR_RGB, CS_PYCC, CS_sRGB, TYPE_2CLR, TYPE_3CLR, TYPE_4CLR, TYPE_5CLR, TYPE_6CLR, TYPE_7CLR, TYPE_8CLR, TYPE_9CLR, TYPE_ACLR, TYPE_BCLR, TYPE_CCLR, TYPE_CMY, TYPE_CMYK, TYPE_DCLR, TYPE_ECLR, TYPE_FCLR, TYPE_GRAY, TYPE_HLS, TYPE_HSV, TYPE_Lab, TYPE_Luv, TYPE_RGB, TYPE_XYZ, TYPE_YCbCr, TYPE_Yxy

Constructor Summary

Constructors

Constructor and Description
CIELABColorSpace()

Method Summary

Modifier and Type	Method and Description
float[]	fromCIEXYZ(float[] colorvalue) XYT to Lab.
float[]	fromRGB(float[] rgbvalue)
float	getMaxValue(int component)
float	getMinValue(int component)
java.lang.String	getName()
java.lang.String	getName(int component)
CIELABColorSpace.OutsideGamutHandling	getOutsideGamutHandling()
static void	main(java.lang.String[] arg)
void	setOutsideGamutHandling(CIELABColorSpace.OutsideGamutHandling b)
float[]	toCIEXYZ(float[] colorvalue) Lab to XYZ.
float[]	toRGB(float[] colorvalue)

Methods inherited from class java.awt.color.ColorSpace

getInstance, getNumComponents, getType, isCS_sRGB

Methods inherited from class java.lang.Object

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

Constructor Detail

CIELABColorSpace

public CIELABColorSpace()

Method Detail

toRGB

public float[] toRGB(float[] colorvalue)

Specified by:

toRGB in class java.awt.color.ColorSpace

fromRGB

public float[] fromRGB(float[] rgbvalue)

Specified by:

fromRGB in class java.awt.color.ColorSpace

toCIEXYZ

public float[] toCIEXYZ(float[] colorvalue)

Lab to XYZ.

 X = xr*Xw;
 Y = yr*Yw;
 Z = zr*Zw;
 

where

 xr = fx^3, if fx^3 > eps
    = (116*fx - 16)/k, if fx^3 <= eps

 yr = ((L+16)/116)^3, if L > k*eps
    = L/k, if L <= k*eps

 zr = fz^3, if fz^3 > eps
    = (116*fz - 16)/k, if fz^3 <= eps

 fx = a/500+fy

 fz = fy - b / 200

 fy = (L+16)/116

 eps = 216/24389
 k = 24389/27
 

Source: http://www.brucelindbloom.com/index.html?Equations.html

Specified by:

toCIEXYZ in class java.awt.color.ColorSpace

Parameters:

colorvalue - Lab color value.

Returns:

CIEXYZ color value.

fromCIEXYZ

public float[] fromCIEXYZ(float[] colorvalue)

XYT to Lab.

 L = 116*fy - 16
 a = 500 * (fx - fy)
 b = 200 * (fy - fz)
 

where

 fx = xr^(1/3), if xr > eps
    = (k*xr + 16) / 116 if xr <= eps

 fy = yr^(1/3), if yr > eps
    = (k*yr + 16) / 116 if yr <= eps

 fz = zr^(1/3), if zr > eps
    = (k*zr + 16) / 116 if zr <= eps

 xr = X / Xw
 yr = Y / Yw
 zr = Z / Zw

 eps = 216/24389
 k = 24389/27
 

Source: http://www.brucelindbloom.com/index.html?Equations.html

Specified by:

fromCIEXYZ in class java.awt.color.ColorSpace

Parameters:

colorvalue - CIEXYZ color value.

Returns:

Lab color value.

getName

public java.lang.String getName()

Specified by:

getName in interface NamedColorSpace

getMinValue

public float getMinValue(int component)

Overrides:

getMinValue in class java.awt.color.ColorSpace

getMaxValue

public float getMaxValue(int component)

Overrides:

getMaxValue in class java.awt.color.ColorSpace

getName

public java.lang.String getName(int component)

Overrides:

getName in class java.awt.color.ColorSpace

setOutsideGamutHandling

public void setOutsideGamutHandling(CIELABColorSpace.OutsideGamutHandling b)

getOutsideGamutHandling

public CIELABColorSpace.OutsideGamutHandling getOutsideGamutHandling()

main

public static void main(java.lang.String[] arg)