Module java.desktop

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

    Fields
    Modifier and Type
    Field
    Description
    static final int
    The built-in CIEXYZ conversion color space defined above.
    static final int
    The built-in linear gray scale color space.
    static final int
    The built-in linear RGB color space.
    static final int
    The built-in Photo YCC conversion color space.
    static final int
    The built-in sRGB color space defined at http://www.w3.org/pub/WWW/Graphics/Color/sRGB.html.
    static final int
    Generic 2 component color spaces.
    static final int
    Generic 3 component color spaces.
    static final int
    Generic 4 component color spaces.
    static final int
    Generic 5 component color spaces.
    static final int
    Generic 6 component color spaces.
    static final int
    Generic 7 component color spaces.
    static final int
    Generic 8 component color spaces.
    static final int
    Generic 9 component color spaces.
    static final int
    Generic 10 component color spaces.
    static final int
    Generic 11 component color spaces.
    static final int
    Generic 12 component color spaces.
    static final int
    Any of the family of CMY color spaces.
    static final int
    Any of the family of CMYK color spaces.
    static final int
    Generic 13 component color spaces.
    static final int
    Generic 14 component color spaces.
    static final int
    Generic 15 component color spaces.
    static final int
    Any of the family of GRAY color spaces.
    static final int
    Any of the family of HLS color spaces.
    static final int
    Any of the family of HSV color spaces.
    static final int
    Any of the family of Lab color spaces.
    static final int
    Any of the family of Luv color spaces.
    static final int
    Any of the family of RGB color spaces.
    static final int
    Any of the family of XYZ color spaces.
    static final int
    Any of the family of YCbCr color spaces.
    static final int
    Any of the family of Yxy color spaces.
  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    ColorSpace​(int type, int numComponents)
    Constructs a ColorSpace object given a color space type and the number of components.
  • Method Summary

    Modifier and Type
    Method
    Description
    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 cspace)
    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.
    getName​(int component)
    Returns the name of the component given the component index.
    int
    Returns the number of components of this ColorSpace.
    int
    Returns the color space type of this ColorSpace (for example TYPE_RGB, TYPE_XYZ, ...).
    boolean
    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 declared in class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

  • Constructor Details

    • 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 Details

    • getInstance

      public static ColorSpace getInstance(int cspace)
      Returns a ColorSpace representing one of the specific predefined color spaces.
      Parameters:
      cspace - 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 component)
      Returns the name of the component given the component index.
      Parameters:
      component - the component index
      Returns:
      the name of the component at the specified index
      Throws:
      IllegalArgumentException - if component is less than 0 or greater than numComponents - 1
    • 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