Eclipse Rich Ajax Platform

org.eclipse.swt.graphics
Class PaletteData

java.lang.Object
  extended by org.eclipse.swt.graphics.PaletteData

public final class PaletteData
extends java.lang.Object

Instances of this class describe the color data used by an image.

Depending on the depth of the image, the PaletteData can take one of two forms, indicated by the isDirect field:

isDirect is false
If isDirect is false, this palette is an indexed palette which maps pixel values to RGBs. The actual RGB values may be retrieved by using the getRGBs() method.
isDirect is true
If isDirect is true, this palette is a direct color palette. Instead of containing RGB values, it contains red, green and blue mask and shift information which indicates how the color components may be extracted from a given pixel. This means that the RGB value is actually encoded in the pixel value.

In this case, the shift data is the number of bits required to shift the RGB value to the left in order to align the high bit of the corresponding mask with the high bit of the first byte. This number may be negative, so care must be taken when shifting. For example, with a red mask of 0xFF0000, the red shift would be -16. With a red mask of 0x1F, the red shift would be 3.

Since:
1.3
See Also:
Image, RGB

Field Summary
 int blueMask
          the blue mask for a direct palette
 int blueShift
          the blue shift for a direct palette
 RGB[] colors
          the RGB values for an indexed palette, where the indices of the array correspond to pixel values
 int greenMask
          the green mask for a direct palette
 int greenShift
          the green shift for a direct palette
 boolean isDirect
          true if the receiver is a direct palette, and false otherwise
 int redMask
          the red mask for a direct palette
 int redShift
          the red shift for a direct palette
 
Constructor Summary
PaletteData(int redMask, int greenMask, int blueMask)
          Constructs a new direct palette given the red, green and blue masks.
PaletteData(RGB[] colors)
          Constructs a new indexed palette given an array of RGB values.
 
Method Summary
 int getPixel(RGB rgb)
          Returns the pixel value corresponding to the given RGB.
 RGB getRGB(int pixel)
          Returns an RGB corresponding to the given pixel value.
 RGB[] getRGBs()
          Returns all the RGB values in the receiver if it is an indexed palette, or null if it is a direct palette.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

isDirect

public boolean isDirect
true if the receiver is a direct palette, and false otherwise


colors

public RGB[] colors
the RGB values for an indexed palette, where the indices of the array correspond to pixel values


redMask

public int redMask
the red mask for a direct palette


greenMask

public int greenMask
the green mask for a direct palette


blueMask

public int blueMask
the blue mask for a direct palette


redShift

public int redShift
the red shift for a direct palette


greenShift

public int greenShift
the green shift for a direct palette


blueShift

public int blueShift
the blue shift for a direct palette

Constructor Detail

PaletteData

public PaletteData(RGB[] colors)
Constructs a new indexed palette given an array of RGB values.

Parameters:
colors - the array of RGBs for the palette
Throws:
java.lang.IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the argument is null

PaletteData

public PaletteData(int redMask,
                   int greenMask,
                   int blueMask)
Constructs a new direct palette given the red, green and blue masks.

Parameters:
redMask - the red mask
greenMask - the green mask
blueMask - the blue mask
Method Detail

getPixel

public int getPixel(RGB rgb)
Returns the pixel value corresponding to the given RGB.

Parameters:
rgb - the RGB to get the pixel value for
Returns:
the pixel value for the given RGB
Throws:
java.lang.IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the argument is null
  • ERROR_INVALID_ARGUMENT - if the RGB is not found in the palette

getRGB

public RGB getRGB(int pixel)
Returns an RGB corresponding to the given pixel value.

Parameters:
pixel - the pixel to get the RGB value for
Returns:
the RGB value for the given pixel
Throws:
java.lang.IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the argument is null
  • ERROR_INVALID_ARGUMENT - if the pixel does not exist in the palette

getRGBs

public RGB[] getRGBs()
Returns all the RGB values in the receiver if it is an indexed palette, or null if it is a direct palette.

Returns:
the RGBs for the receiver or null

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