Package org.eclipse.swt.graphics

Class PaletteData

java.lang.Object
org.eclipse.swt.graphics.PaletteData
public final class PaletteData extends 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.

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    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

    Constructors
    Constructor
    Description
    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

    Modifier and Type
    Method
    Description
    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 Details

    • 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 Details

    • 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:
      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 Details

    • 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:
      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:
      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