PDAP Public Review Draft

java.awt.image
Class IndexColorModel

java.lang.Object
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  +--java.awt.image.ColorModel
        |
        +--java.awt.image.IndexColorModel

public class IndexColorModel
extends ColorModel

The IndexColorModel class is a ColorModel class that works with pixel values consisting of a single sample which is an index into a fixed colormap in the default sRGB. The colormap specifies red, green, blue, and optional alpha components corresponding to each index. All components are represented in the colormap as 8-bit unsigned integral values. If alpha is not present, an opaque alpha component (alpha = 1.0) is assumed for each entry. An optional transparent pixel value can be supplied that indicates a completely transparent pixel, regardless of any alpha component recorded for that pixel value. Note that alpha values in IndexColorModel objects are never premultiplied. This color model is similar to an X11 PseudoColor visual.

The index represented by a pixel value is stored in the least significant n bits of the pixel representations passed to the methods of this class, where n is the pixel size specified to the constructor for a particular IndexColorModel object and n must be between 1 and 16. Higher order bits in pixel representations are assumed to be zero. For those methods that use a primitive array pixel representation of type transferType, the array length is always one. The transfer types supported are DataBuffer.TYPE_BYTE and DataBuffer.TYPE_USHORT. A single int pixel representation is valid for all objects of this class, since it is always possible to represent pixel values used with this class in a single int. Therefore, methods that use this representation do not throw an IllegalArgumentException due to an invalid pixel value.

Many of the methods in this class are final. The reason for this is that the underlying native graphics code makes assumptions about the layout and operation of this class and those assumptions are reflected in the implementations of the methods here that are marked final. You can subclass this class for other reaons, but you cannot override or modify the behaviour of those methods.

See Also:
ColorModel

Fields inherited from class java.awt.image.ColorModel
pixel_bits
 
Constructor Summary
IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b)
          Constructs an IndexColorModel from the specified arrays of red, green, and blue components.
IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b, byte[] a)
          Constructs an IndexColorModel from the given arrays of red, green, blue and alpha components.
IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b, int trans)
          Constructs an IndexColorModel from the given arrays of red, green, and blue components.
IndexColorModel(int bits, int size, byte[] cmap, int start, boolean hasalpha)
          Constructs an IndexColorModel from a single array of interleaved red, green, blue and optional alpha components.
IndexColorModel(int bits, int size, byte[] cmap, int start, boolean hasalpha, int trans)
          Constructs an IndexColorModel from a single array of interleaved red, green, blue and optional alpha components.
 
Method Summary
 void finalize()
          Disposes of system resources associated with this ColorModel once this ColorModel is no longer referenced.
 int getAlpha(int pixel)
          Returns the alpha component for the specified pixel, scaled from 0 to 255.
 void getAlphas(byte[] a)
          Copies the array of alpha transparency components into the specified array.
 int getBlue(int pixel)
          Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB.
 void getBlues(byte[] b)
          Copies the array of blue color components into the specified array.
 int getGreen(int pixel)
          Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB.
 void getGreens(byte[] g)
          Copies the array of green color components into the specified array.
 int getMapSize()
          Returns the size of the color/alpha component arrays in this IndexColorModel.
 int getRed(int pixel)
          Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB.
 void getReds(byte[] r)
          Copies the array of red color components into the specified array.
 int getRGB(int pixel)
          Returns the color/alpha components of the pixel in the default RGB color model format.
 void getRGBs(int[] rgb)
          Converts data for each index from the color and alpha component arrays to an int in the default RGB ColorModel format and copies the resulting 32-bit ARGB values into the specified array.
 int getTransparentPixel()
          Returns the index of the transparent pixel in this IndexColorModel or -1 if there is no transparent pixel.
 java.lang.String toString()
          Returns the String representation of the contents of this ColorModelobject.
 
Methods inherited from class java.awt.image.ColorModel
equals, getPixelSize, getRGBdefault, hasAlpha, hashCode, isAlphaPremultiplied
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

IndexColorModel

public IndexColorModel(int bits,
                       int size,
                       byte[] r,
                       byte[] g,
                       byte[] b)
Constructs an IndexColorModel from the specified arrays of red, green, and blue components. Pixels described by this color model all have alpha components of 255 unnormalized (1.0 normalized), which means they are fully opaque. All of the arrays specifying the color components must have at least the specified number of entries.
Parameters:
bits - the number of bits each pixel occupies
size - the size of the color component arrays
r - the array of red color components
g - the array of green color components
b - the array of blue color components
Throws:
java.lang.IllegalArgumentException - if bits is less than 1 or greater than 16
java.lang.IllegalArgumentException - if size is less than 1

IndexColorModel

public IndexColorModel(int bits,
                       int size,
                       byte[] r,
                       byte[] g,
                       byte[] b,
                       int trans)
Constructs an IndexColorModel from the given arrays of red, green, and blue components. Pixels described by this color model all have alpha components of 255 unnormalized (1.0 normalized), which means they are fully opaque, except for the indicated transparent pixel. All of the arrays specifying the color components must have at least the specified number of entries.
Parameters:
bits - the number of bits each pixel occupies
size - the size of the color component arrays
r - the array of red color components
g - the array of green color components
b - the array of blue color components
trans - the index of the transparent pixel
Throws:
java.lang.IllegalArgumentException - if bits is less than 1 or greater than 16
java.lang.IllegalArgumentException - if size is less than 1

IndexColorModel

public IndexColorModel(int bits,
                       int size,
                       byte[] r,
                       byte[] g,
                       byte[] b,
                       byte[] a)
Constructs an IndexColorModel from the given arrays of red, green, blue and alpha components. All of the arrays specifying the components must have at least the specified number of entries.
Parameters:
bits - the number of bits each pixel occupies
size - the size of the color component arrays
r - the array of red color components
g - the array of green color components
b - the array of blue color components
a - the array of alpha value components
Throws:
java.lang.IllegalArgumentException - if bits is less than 1 or greater than 16
java.lang.IllegalArgumentException - if size is less than 1

IndexColorModel

public IndexColorModel(int bits,
                       int size,
                       byte[] cmap,
                       int start,
                       boolean hasalpha)
Constructs an IndexColorModel from a single array of interleaved red, green, blue and optional alpha components. The array must have enough values in it to fill all of the needed component arrays of the specified size.
Parameters:
bits - the number of bits each pixel occupies
size - the size of the color component arrays
cmap - the array of color components
start - the starting offset of the first color component
hasalpha - indicates whether alpha values are contained in the cmap array
Throws:
java.lang.IllegalArgumentException - if bits is less than 1 or greater than 16
java.lang.IllegalArgumentException - if size is less than 1

IndexColorModel

public IndexColorModel(int bits,
                       int size,
                       byte[] cmap,
                       int start,
                       boolean hasalpha,
                       int trans)
Constructs an IndexColorModel from a single array of interleaved red, green, blue and optional alpha components. The specified transparent index represents a pixel that is considered entirely transparent regardless of any alpha value specified for it. The array must have enough values in it to fill all of the needed component arrays of the specified size.
Parameters:
bits - the number of bits each pixel occupies
size - the size of the color component arrays
cmap - the array of color components
start - the starting offset of the first color component
hasalpha - indicates whether alpha values are contained in the cmap array
trans - the index of the fully transparent pixel
Throws:
java.lang.IllegalArgumentException - if bits is less than 1 or greater than 16
java.lang.IllegalArgumentException - if size is less than 1
Method Detail

getMapSize

public final int getMapSize()
Returns the size of the color/alpha component arrays in this IndexColorModel.
Returns:
the size of the color and alpha component arrays.

getTransparentPixel

public final int getTransparentPixel()
Returns the index of the transparent pixel in this IndexColorModel or -1 if there is no transparent pixel.
Returns:
the index of this IndexColorModel object's transparent pixel, or -1 if there is no such pixel.

getReds

public final void getReds(byte[] r)
Copies the array of red color components into the specified array. Only the initial entries of the array as specified by getMapSize are written.
Parameters:
r - the specified array into which the elements of the array of red color components are copied

getGreens

public final void getGreens(byte[] g)
Copies the array of green color components into the specified array. Only the initial entries of the array as specified by getMapSize are written.
Parameters:
g - the specified array into which the elements of the array of green color components are copied

getBlues

public final void getBlues(byte[] b)
Copies the array of blue color components into the specified array. Only the initial entries of the array as specified by getMapSize are written.
Parameters:
b - the specified array into which the elements of the array of blue color components are copied

getAlphas

public final void getAlphas(byte[] a)
Copies the array of alpha transparency components into the specified array. Only the initial entries of the array as specified by getMapSize are written.
Parameters:
a - the specified array into which the elements of the array of alpha components are copied

getRGBs

public final void getRGBs(int[] rgb)
Converts data for each index from the color and alpha component arrays to an int in the default RGB ColorModel format and copies the resulting 32-bit ARGB values into the specified array. Only the initial entries of the array as specified by getMapSize are written.
Parameters:
rgb - the specified array into which the converted ARGB values from this array of color and alpha components are copied.

getRed

public final int getRed(int pixel)
Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB. The pixel value is specified as an int. The returned value is a non pre-multiplied value.
Overrides:
getRed in class ColorModel
Parameters:
pixel - the specified pixel
Returns:
the value of the red color component for the specified pixel

getGreen

public final int getGreen(int pixel)
Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB. The pixel value is specified as an int. The returned value is a non pre-multiplied value.
Overrides:
getGreen in class ColorModel
Parameters:
pixel - the specified pixel
Returns:
the value of the green color component for the specified pixel

getBlue

public final int getBlue(int pixel)
Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB. The pixel value is specified as an int. The returned value is a non pre-multiplied value.
Overrides:
getBlue in class ColorModel
Parameters:
pixel - the specified pixel
Returns:
the value of the blue color component for the specified pixel

getAlpha

public final int getAlpha(int pixel)
Returns the alpha component for the specified pixel, scaled from 0 to 255. The pixel value is specified as an int.
Overrides:
getAlpha in class ColorModel
Parameters:
pixel - the specified pixel
Returns:
the value of the alpha component for the specified pixel

getRGB

public final int getRGB(int pixel)
Returns the color/alpha components of the pixel in the default RGB color model format. The pixel value is specified as an int. The returned value is in a non pre-multiplied format.
Overrides:
getRGB in class ColorModel
Parameters:
pixel - the specified pixel
Returns:
the color and alpha components of the specified pixel
See Also:
ColorModel.getRGBdefault()

finalize

public void finalize()
Disposes of system resources associated with this ColorModel once this ColorModel is no longer referenced.
Overrides:
finalize in class ColorModel

toString

public java.lang.String toString()
Returns the String representation of the contents of this ColorModelobject.
Overrides:
toString in class ColorModel
Returns:
a String representing the contents of this ColorModel object.

PDAP 1.0 Spec, Rev. 0.16