java.awt.color
Class ColorSpace

java.lang.Object
  |
  +--java.awt.color.ColorSpace

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

ICC_ColorSpace

public abstract class ColorSpace

extends Object

implements Serializable

This abstract class is used to serve as a color space tag to identify the specific color space of a Color object or, via a ColorModel object, of an Image, a BufferedImage, or a GraphicsDevice. It contains methods that transform colors in a specific color space to/from sRGB and to/from a well-defined CIEXYZ color space.

For purposes of the methods in this class, colors are represented as arrays of color components represented as floats in a normalized range defined by each ColorSpace. For many ColorSpaces (e.g. sRGB), this range is 0.0 to 1.0. However, some ColorSpaces have components whose values have a different range. Methods are provided to inquire per component minimum and maximum normalized values.

Several variables are defined for purposes of referring to color space types (e.g. TYPE_RGB, TYPE_XYZ, etc.) and to refer to specific color spaces (e.g. CS_sRGB and CS_CIEXYZ). sRGB is a proposed standard RGB color space. For more information, see http://www.w3.org/pub/WWW/Graphics/Color/sRGB.html .

The purpose of the methods to transform to/from the well-defined CIEXYZ color space is to support conversions between any two color spaces at a reasonably high degree of accuracy. It is expected that particular implementations of subclasses of ColorSpace (e.g. ICC_ColorSpace) will support high performance conversion based on underlying platform color management systems.

The CS_CIEXYZ space used by the toCIEXYZ/fromCIEXYZ methods can be described as follows:

 
       CIEXYZ
       viewing illuminance: 200 lux
       viewing white point: CIE D50
       media white point: "that of a perfectly reflecting diffuser" -- D50 
       media black point: 0 lux or 0 Reflectance
       flare: 1 percent
       surround: 20percent of the media white point
       media description: reflection print (i.e., RLAB, Hunt viewing media)
       note: For developers creating an ICC profile for this conversion
             space, the following is applicable.  Use a simple Von Kries
             white point adaptation folded into the 3X3 matrix parameters
             and fold the flare and surround effects into the three
             one-dimensional lookup tables (assuming one uses the minimal
             model for monitors).
 
 

See Also:

ICC_ColorSpace, Serialized Form

Field Summary

static int	CS_CIEXYZ The CIEXYZ conversion color space defined above.
static int	CS_GRAY The built-in linear gray scale color space.
static int	CS_LINEAR_RGB A built-in linear RGB color space.
static int	CS_PYCC The Photo YCC conversion color space.
static int	CS_sRGB The sRGB color space defined at http://www.w3.org/pub/WWW/Graphics/Color/sRGB.html .
static int	TYPE_2CLR Generic 2 component color spaces.
static int	TYPE_3CLR Generic 3 component color spaces.
static int	TYPE_4CLR Generic 4 component color spaces.
static int	TYPE_5CLR Generic 5 component color spaces.
static int	TYPE_6CLR Generic 6 component color spaces.
static int	TYPE_7CLR Generic 7 component color spaces.
static int	TYPE_8CLR Generic 8 component color spaces.
static int	TYPE_9CLR Generic 9 component color spaces.
static int	TYPE_ACLR Generic 10 component color spaces.
static int	TYPE_BCLR Generic 11 component color spaces.
static int	TYPE_CCLR Generic 12 component color spaces.
static int	TYPE_CMY Any of the family of CMY color spaces.
static int	TYPE_CMYK Any of the family of CMYK color spaces.
static int	TYPE_DCLR Generic 13 component color spaces.
static int	TYPE_ECLR Generic 14 component color spaces.
static int	TYPE_FCLR Generic 15 component color spaces.
static int	TYPE_GRAY Any of the family of GRAY color spaces.
static int	TYPE_HLS Any of the family of HLS color spaces.
static int	TYPE_HSV Any of the family of HSV color spaces.
static int	TYPE_Lab Any of the family of Lab color spaces.
static int	TYPE_Luv Any of the family of Luv color spaces.
static int	TYPE_RGB Any of the family of RGB color spaces.
static int	TYPE_XYZ Any of the family of XYZ color spaces.
static int	TYPE_YCbCr Any of the family of YCbCr color spaces.
static int	TYPE_Yxy Any of the family of Yxy color spaces.

Constructor Summary

protected

ColorSpace(int type, int numcomponents) Constructs a ColorSpace object given a color space type and the number of components.

Method Summary

abstract float[]	fromCIEXYZ(float[] colorvalue) Transforms a color value assumed to be in the CS_CIEXYZ conversion color space into this ColorSpace.
abstract float[]	fromRGB(float[] rgbvalue) Transforms a color value assumed to be in the default CS_sRGB color space into this ColorSpace.
static ColorSpace	getInstance(int colorspace) Returns a ColorSpace representing one of the specific predefined color spaces.
float	getMaxValue(int component) Returns the maximum normalized color component value for the specified component.
float	getMinValue(int component) Returns the minimum normalized color component value for the specified component.
String	getName(int idx) Returns the name of the component given the component index.
int	getNumComponents() Returns the number of components of this ColorSpace.
int	getType() Returns the color space type of this ColorSpace (for example TYPE_RGB, TYPE_XYZ, ...).
boolean	isCS_sRGB() Returns true if the ColorSpace is CS_sRGB.
abstract float[]	toCIEXYZ(float[] colorvalue) Transforms a color value assumed to be in this ColorSpace into the CS_CIEXYZ conversion color space.
abstract float[]	toRGB(float[] colorvalue) Transforms a color value assumed to be in this ColorSpace into a value in the default CS_sRGB color space.

Methods inherited from class java.lang.Object

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

Field Detail

TYPE_XYZ

public static final int TYPE_XYZ

Any of the family of XYZ color spaces.

See Also:

Constant Field Values

TYPE_Lab

public static final int TYPE_Lab

Any of the family of Lab color spaces.

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Constant Field Values

TYPE_Luv

public static final int TYPE_Luv

Any of the family of Luv color spaces.

See Also:

Constant Field Values

TYPE_YCbCr

public static final int TYPE_YCbCr

Any of the family of YCbCr color spaces.

See Also:

Constant Field Values

TYPE_Yxy

public static final int TYPE_Yxy

Any of the family of Yxy color spaces.

See Also:

Constant Field Values

TYPE_RGB

public static final int TYPE_RGB

Any of the family of RGB color spaces.

See Also:

Constant Field Values

TYPE_GRAY

public static final int TYPE_GRAY

Any of the family of GRAY color spaces.

See Also:

Constant Field Values

TYPE_HSV

public static final int TYPE_HSV

Any of the family of HSV color spaces.

See Also:

Constant Field Values

TYPE_HLS

public static final int TYPE_HLS

Any of the family of HLS color spaces.

See Also:

Constant Field Values

TYPE_CMYK

public static final int TYPE_CMYK

Any of the family of CMYK color spaces.

See Also:

Constant Field Values

TYPE_CMY

public static final int TYPE_CMY

Any of the family of CMY color spaces.

See Also:

Constant Field Values

TYPE_2CLR

public static final int TYPE_2CLR

Generic 2 component color spaces.

See Also:

Constant Field Values

TYPE_3CLR

public static final int TYPE_3CLR

Generic 3 component color spaces.

See Also:

Constant Field Values

TYPE_4CLR

public static final int TYPE_4CLR

Generic 4 component color spaces.

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Constant Field Values

TYPE_5CLR

public static final int TYPE_5CLR

Generic 5 component color spaces.

See Also:

Constant Field Values

TYPE_6CLR

public static final int TYPE_6CLR

Generic 6 component color spaces.

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Constant Field Values

TYPE_7CLR

public static final int TYPE_7CLR

Generic 7 component color spaces.

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Constant Field Values

TYPE_8CLR

public static final int TYPE_8CLR

Generic 8 component color spaces.

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Constant Field Values

TYPE_9CLR

public static final int TYPE_9CLR

Generic 9 component color spaces.

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Constant Field Values

TYPE_ACLR

public static final int TYPE_ACLR

Generic 10 component color spaces.

See Also:

Constant Field Values

TYPE_BCLR

public static final int TYPE_BCLR

Generic 11 component color spaces.

See Also:

Constant Field Values

TYPE_CCLR

public static final int TYPE_CCLR

Generic 12 component color spaces.

See Also:

Constant Field Values

TYPE_DCLR

public static final int TYPE_DCLR

Generic 13 component color spaces.

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Constant Field Values

TYPE_ECLR

public static final int TYPE_ECLR

Generic 14 component color spaces.

See Also:

Constant Field Values

TYPE_FCLR

public static final int TYPE_FCLR

Generic 15 component color spaces.

See Also:

Constant Field Values

CS_sRGB

public static final int CS_sRGB

The sRGB color space defined at http://www.w3.org/pub/WWW/Graphics/Color/sRGB.html .

See Also:

Constant Field Values

CS_LINEAR_RGB

public static final int CS_LINEAR_RGB

A built-in linear RGB color space. This space is based on the same RGB primaries as CS_sRGB, but has a linear tone reproduction curve.

See Also:

Constant Field Values

CS_CIEXYZ

public static final int CS_CIEXYZ

The CIEXYZ conversion color space defined above.

See Also:

Constant Field Values

CS_PYCC

public static final int CS_PYCC

The Photo YCC conversion color space.

See Also:

Constant Field Values

CS_GRAY

public static final int CS_GRAY

The built-in linear gray scale color space.

See Also:

Constant Field Values

Constructor Detail

ColorSpace

protected ColorSpace(int type,
                     int numcomponents)

Constructs a ColorSpace object given a color space type and the number of components.

Parameters:

type - One of the ColorSpace type constants.

numcomponents - The number of components in the color space.

Method Detail

getInstance

public static ColorSpace getInstance(int colorspace)

Returns a ColorSpace representing one of the specific predefined color spaces.

Parameters:

colorspace - a specific color space identified by one of the predefined class constants (e.g. CS_sRGB, CS_LINEAR_RGB, CS_CIEXYZ, CS_GRAY, or CS_PYCC)

Returns:

The requested ColorSpace object.

isCS_sRGB

public boolean isCS_sRGB()

Returns true if the ColorSpace is CS_sRGB.

Returns:

true if this is a CS_sRGB color space, false if it is not.

toRGB

public abstract float[] toRGB(float[] colorvalue)

Transforms a color value assumed to be in this ColorSpace into a value in the default CS_sRGB color space.

This method transforms color values using algorithms designed to produce the best perceptual match between input and output colors. In order to do colorimetric conversion of color values, you should use the toCIEXYZ method of this color space to first convert from the input color space to the CS_CIEXYZ color space, and then use the fromCIEXYZ method of the CS_sRGB color space to convert from CS_CIEXYZ to the output color space. See toCIEXYZ and fromCIEXYZ for further information.

Parameters:

colorvalue - a float array with length of at least the number of components in this ColorSpace

Returns:

a float array of length 3

Throws:

ArrayIndexOutOfBoundsException - if array length is not at least the number of components in this ColorSpace.

fromRGB

public abstract float[] fromRGB(float[] rgbvalue)

Transforms a color value assumed to be in the default CS_sRGB color space into this ColorSpace.

This method transforms color values using algorithms designed to produce the best perceptual match between input and output colors. In order to do colorimetric conversion of color values, you should use the toCIEXYZ method of the CS_sRGB color space to first convert from the input color space to the CS_CIEXYZ color space, and then use the fromCIEXYZ method of this color space to convert from CS_CIEXYZ to the output color space. See toCIEXYZ and fromCIEXYZ for further information.

Parameters:

rgbvalue - a float array with length of at least 3

Returns:

a float array with length equal to the number of components in this ColorSpace

Throws:

ArrayIndexOutOfBoundsException - if array length is not at least 3.

toCIEXYZ

public abstract float[] toCIEXYZ(float[] colorvalue)

Transforms a color value assumed to be in this ColorSpace into the CS_CIEXYZ conversion color space.

This method transforms color values using relative colorimetry, as defined by the International Color Consortium standard. This means that the XYZ values returned by this method are represented relative to the D50 white point of the CS_CIEXYZ color space. This representation is useful in a two-step color conversion process in which colors are transformed from an input color space to CS_CIEXYZ and then to an output color space. This representation is not the same as the XYZ values that would be measured from the given color value by a colorimeter. A further transformation is necessary to compute the XYZ values that would be measured using current CIE recommended practices. See the toCIEXYZ method of ICC_ColorSpace for further information.

Parameters:

colorvalue - a float array with length of at least the number of components in this ColorSpace

Returns:

a float array of length 3

Throws:

ArrayIndexOutOfBoundsException - if array length is not at least the number of components in this ColorSpace.

fromCIEXYZ

public abstract float[] fromCIEXYZ(float[] colorvalue)

Transforms a color value assumed to be in the CS_CIEXYZ conversion color space into this ColorSpace.

This method transforms color values using relative colorimetry, as defined by the International Color Consortium standard. This means that the XYZ argument values taken by this method are represented relative to the D50 white point of the CS_CIEXYZ color space. This representation is useful in a two-step color conversion process in which colors are transformed from an input color space to CS_CIEXYZ and then to an output color space. The color values returned by this method are not those that would produce the XYZ value passed to the method when measured by a colorimeter. If you have XYZ values corresponding to measurements made using current CIE recommended practices, they must be converted to D50 relative values before being passed to this method. See the fromCIEXYZ method of ICC_ColorSpace for further information.

Parameters:

colorvalue - a float array with length of at least 3

Returns:

a float array with length equal to the number of components in this ColorSpace

Throws:

ArrayIndexOutOfBoundsException - if array length is not at least 3.

getType

public int getType()

Returns the color space type of this ColorSpace (for example TYPE_RGB, TYPE_XYZ, ...). The type defines the number of components of the color space and the interpretation, e.g. TYPE_RGB identifies a color space with three components - red, green, and blue. It does not define the particular color characteristics of the space, e.g. the chromaticities of the primaries.

Returns:

The type constant that represents the type of this ColorSpace.

getNumComponents

public int getNumComponents()

Returns the number of components of this ColorSpace.

Returns:

The number of components in this ColorSpace.

getName

public String getName(int idx)

Returns the name of the component given the component index.

Parameters:

idx - The component index.

Returns:

The name of the component at the specified index.

getMinValue

public float getMinValue(int component)

Returns the minimum normalized color component value for the specified component. The default implementation in this abstract class returns 0.0 for all components. Subclasses should override this method if necessary.

Parameters:

component - The component index.

Returns:

The minimum normalized component value.

Throws:

IllegalArgumentException - if component is less than 0 or greater than numComponents - 1.

Since:

1.4

getMaxValue

public float getMaxValue(int component)

Returns the maximum normalized color component value for the specified component. The default implementation in this abstract class returns 1.0 for all components. Subclasses should override this method if necessary.

Parameters:

component - The component index.

Returns:

The maximum normalized component value.

Throws:

IllegalArgumentException - if component is less than 0 or greater than numComponents - 1.

Since:

1.4