Chapter 22
java.awt.image Reference

IndexColorModel

Name

IndexColorModel

[Graphic: Figure from the text]

Description

The IndexColorModel class is a ColorModel that uses a color map lookup table (with a maximum size of 256) to convert pixel values into their alpha, red, green, and blue component parts.

Class Definition

public class java.awt.image.IndexColorModel
    extends java.awt.image.ColorModel {
  // Constructors
  public IndexColorModel (int bits, int size, 
      byte[] colorMap, int start, boolean hasalpha);
  public IndexColorModel (int bits, int size, 
      byte[] colorMap, int start, boolean hasalpha, int transparent);
  public IndexColorModel (int bits, int size, 
      byte[] red, byte[] green, byte[] blue);
  public IndexColorModel (int bits, int size, 
      byte[] red, byte[] green, byte[] blue, byte[] alpha);
  public IndexColorModel (int bits, int size, 
      byte[] red, byte[] green, byte[] blue, int transparent);
  // Instance Methods
  public final int getAlpha (int pixel);
  public final void getAlphas (byte[] alphas);
  public final int getBlue (int pixel);
  public final void getBlues (byte[] blues);
  public final int getGreen (int pixel);
  public final void getGreens (byte[] greens);
  public final int getMapSize();
  public final int getRed (int pixel);
  public final void getReds (byte[] reds);
  public final int getRGB (int pixel);
  public final int getTransparentPixel();
}

Constructors

IndexColorModel

public IndexColorModel (int bits, int size, byte[] colorMap, int start, boolean hasalpha)

Parameters

bits

The number of bits in a pixel.

size

The number of entries in the color map. Note: this is not the size of the colorMap parameter.

colorMap

Color component values in red, green, blue, alpha order; the alpha component is optional, and may not be present.

start

The starting position in colorMap array.

hasalpha

If hasalpha is true, alpha components are present in colorMap array.

Throws

ArrayIndexOutOfBoundsException: If size is invalid.

Description

Constructs an IndexColorModel object with the given component settings. The size of colorMap must be at least 3*size+start, if hasalpha is false; if hasalpha is true, colorMap.length must be at least 4*size+start.

public IndexColorModel (int bits, int size, byte[] colorMap, int start, boolean hasalpha, int transparent)

Parameters

bits

The number of bits in a pixel.

size

The number of entries in the color map. Note: this is not the size of the colorMap parameter.

colorMap

Color component values in red, green, blue, alpha order; the alpha component is optional, and may not be present.

start

The starting position in colorMap array.

hasalpha

If hasalpha is true, alpha components are present in colorMap array.

transparent

Position of colorMap entry for transparent pixel entry.

Throws

ArrayIndexOutOfBoundsException: If size invalid.

Description

public IndexColorModel (int bits, int size, byte[] red, byte[] green, byte[] blue)

Parameters

bits

The number of bits in a pixel.

size

The number of entries in the color map.

red

Red color component values.

green

Green color component values.

blue

Blue color component values.

Throws

ArrayIndexOutOfBoundsException: If size invalid.

Description

Constructs an IndexColorModel object with the given component settings. There is no alpha component. The length of the red, green, and blue arrays must be greater than size.

public IndexColorModel (int bits, int size, byte[] red, byte[] green, byte[] blue, byte[] alpha)

Parameters

bits

The number of bits in a pixel.

size

The number of entries in the color map.

red

Red color component values.

green

Green color component values.

blue

Blue color component values.

alpha

Alpha component values.

Throws

ArrayIndexOutOfBoundsException

If size is invalid.

NullPointerException

If size is positive and alpha array is null.

Description

Constructs an IndexColorModel object with the given component settings. The length of the red, green, blue, and alpha arrays must be greater than size.

public IndexColorModel (int bits, int size, byte[] red, byte[] green, byte[] blue, int transparent)

Parameters

bits

The number of bits in a pixel.

size

The number of entries in the color map.

red

Red color component values.

green

Green color component values.

blue

Blue color component values.

transparent

Position of transparent pixel entry.

Throws

ArrayIndexOutOfBoundsException: If size is invalid.

Description

Constructs an IndexColorModel object with the given component settings. The length of the red, green, blue, and alpha arrays must be greater than size. The color map has a transparent pixel; its location is given by transparent.