Package org.apache.xmlgraphics.java2d.color

Class CIELabColorSpace

java.lang.Object

java.awt.color.ColorSpace

org.apache.xmlgraphics.java2d.color.CIELabColorSpace

All Implemented Interfaces:

Serializable

public class CIELabColorSpace
extends ColorSpace

This class defines the CIE L*a*b* (CIE 1976) color space. Valid values for L* are between 0 and 100, for a* and b* between -127 and +127.

See Also:

• http://en.wikipedia.org/wiki/Lab_color_space
• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private static final String	CIE_LAB_ONLY_HAS_3_COMPONENTS
private static final double	D
private static final double	REF_A
private static final double	REF_B
private static final float	REF_X_D50
private static final float	REF_X_D65
private static final float	REF_Y_D50
private static final float	REF_Y_D65
private static final float	REF_Z_D50
private static final float	REF_Z_D65
private static final long	serialVersionUID
private static final double	T0
private float	wpX
private float	wpY
private float	wpZ

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	Description
CIELabColorSpace()	Default constructor using the D65 white point.
CIELabColorSpace(float[] whitePoint)	CIE Lab space constructor which allows to give an arbitrary white point.

Method Summary

Modifier and Type	Method	Description
private void	checkNumComponents(float[] colorvalue)
private void	checkNumComponents(float[] colorvalue, int expected)
private float	denormalize(float value, int component)
float[]	fromCIEXYZ(float[] colorvalue)
float[]	fromRGB(float[] rgbvalue)
static float[]	getD50WhitePoint()	Returns the D50 white point.
static float[]	getD65WhitePoint()	Returns the D65 white point.
float	getMaxValue(int component)
float	getMinValue(int component)
String	getName(int component)
private float	getNativeValueRange(int component)
float[]	getWhitePoint()	Returns the configured white point.
private float	normalize(float value, int component)
float[]	toCIEXYZ(float[] colorvalue)
float[]	toCIEXYZNative(float l, float a, float b)	Transforms a color value assumed to be in this ColorSpace into the CS_CIEXYZ conversion color space.
Color	toColor(float[] colorvalue, float alpha)	Creates a Color instance from color values usually used by the L*a*b* color space by scaling them to the 0.0..1.0 range expected by Color's constructor.
Color	toColor(float l, float a, float b, float alpha)	Creates a Color instance from color values usually used by the L*a*b* color space by scaling them to the 0.0..1.0 range expected by Color's constructor.
float[]	toNativeComponents(float[] comps)	Converts normalized (0..1) color components to CIE L*a*b*'s native value range.
float[]	toRGB(float[] colorvalue)

Methods inherited from class java.awt.color.ColorSpace

getInstance, getNumComponents, getType, isCS_sRGB

Methods inherited from class java.lang.Object

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

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

REF_X_D65

private static final float REF_X_D65

See Also:

• Constant Field Values

REF_Y_D65

private static final float REF_Y_D65

See Also:

• Constant Field Values

REF_Z_D65

private static final float REF_Z_D65

See Also:

• Constant Field Values

REF_X_D50

private static final float REF_X_D50

See Also:

• Constant Field Values

REF_Y_D50

private static final float REF_Y_D50

See Also:

• Constant Field Values

REF_Z_D50

private static final float REF_Z_D50

See Also:

• Constant Field Values

D

private static final double D

See Also:

• Constant Field Values

REF_A

private static final double REF_A

REF_B

private static final double REF_B

See Also:

• Constant Field Values

T0

private static final double T0

wpX

private float wpX

wpY

private float wpY

wpZ

private float wpZ

CIE_LAB_ONLY_HAS_3_COMPONENTS

private static final String CIE_LAB_ONLY_HAS_3_COMPONENTS

See Also:

• Constant Field Values

Constructor Details

CIELabColorSpace

public CIELabColorSpace()

Default constructor using the D65 white point.

CIELabColorSpace

public CIELabColorSpace(float[] whitePoint)

CIE Lab space constructor which allows to give an arbitrary white point.

Parameters:

whitePoint - the white point in XYZ coordinates (valid values: 0.0f to 1.0f, although values slightly larger than 1.0f are common)

Method Details

getD65WhitePoint

public static float[] getD65WhitePoint()

Returns the D65 white point.

Returns:

the D65 white point.

getD50WhitePoint

public static float[] getD50WhitePoint()

Returns the D50 white point.

Returns:

the D50 white point.

checkNumComponents

private void checkNumComponents(float[] colorvalue)

checkNumComponents

private void checkNumComponents(float[] colorvalue,
 int expected)

getWhitePoint

public float[] getWhitePoint()

Returns the configured white point.

Returns:

the white point in CIE XYZ coordinates

getMinValue

public float getMinValue(int component)

Overrides:

getMinValue in class ColorSpace

getMaxValue

public float getMaxValue(int component)

Overrides:

getMaxValue in class ColorSpace

getName

public String getName(int component)

Overrides:

getName in class ColorSpace

fromCIEXYZ

public float[] fromCIEXYZ(float[] colorvalue)

Specified by:

fromCIEXYZ in class ColorSpace

fromRGB

public float[] fromRGB(float[] rgbvalue)

Specified by:

fromRGB in class ColorSpace

toCIEXYZ

public float[] toCIEXYZ(float[] colorvalue)

Specified by:

toCIEXYZ in class ColorSpace

toCIEXYZNative

public float[] toCIEXYZNative(float l,
 float a,
 float b)

Transforms a color value assumed to be in this ColorSpace into the CS_CIEXYZ conversion color space. This method uses component values in CIE Lab's native color ranges rather than the normalized values between 0 and 1.

Parameters:

l - the L* component (values between 0 and 100)

a - the a* component (usually between -128 and +128)

b - the b* component (usually between -128 and +128)

Returns:

the XYZ color values

See Also:

• toCIEXYZ(float[])

toRGB

public float[] toRGB(float[] colorvalue)

Specified by:

toRGB in class ColorSpace

getNativeValueRange

private float getNativeValueRange(int component)

normalize

private float normalize(float value,
 int component)

denormalize

private float denormalize(float value,
 int component)

toNativeComponents

public float[] toNativeComponents(float[] comps)

Converts normalized (0..1) color components to CIE L*a*b*'s native value range.

Parameters:

comps - the normalized components.

Returns:

the denormalized components

toColor

public Color toColor(float[] colorvalue,
 float alpha)

Creates a Color instance from color values usually used by the L*a*b* color space by scaling them to the 0.0..1.0 range expected by Color's constructor.

Parameters:

colorvalue - the original color values (native value range, i.e. not normalized to 0.0..1.0)

alpha - the alpha component

Returns:

the requested color instance

toColor

public Color toColor(float l,
 float a,
 float b,
 float alpha)

Creates a Color instance from color values usually used by the L*a*b* color space by scaling them to the 0.0..1.0 range expected by Color's constructor.

Parameters:

l - the L* component (values between 0 and 100)

a - the a* component (usually between -128 and +127)

b - the b* component (usually between -128 and +127)

alpha - the alpha component (values between 0 and 1)

Returns:

the requested color instance