java.awt.image
Class DirectColorModel

java.lang.Object
  |
  +--java.awt.image.ColorModel
        |
        +--java.awt.image.PackedColorModel
              |
              +--java.awt.image.DirectColorModel
All Implemented Interfaces:
Transparency
public class DirectColorModel
extends PackedColorModel

The DirectColorModel class is a ColorModel class that works with pixel values that represent RGB color and alpha information as separate samples and that pack all samples for a single pixel into a single int, short, or byte quantity. This class can be used only with ColorSpaces of type ColorSpace.TYPE_RGB. In addition, for each component of the ColorSpace, the minimum normalized component value obtained via the getMinValue() method of ColorSpace must be 0.0, and the maximum value obtained via the getMaxValue() method must be 1.0 (these min/max values are typical for RGB spaces). There must be three color samples in the pixel values and there can be a single alpha sample. 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, DataBuffer.TYPE_USHORT, and DataBuffer.TYPE_INT. Color and alpha samples are stored in the single element of the array in bits indicated by bit masks. Each bit mask must be contiguous and masks must not overlap. The same masks apply to the single int pixel representation used by other methods. The correspondence of masks and color/alpha samples is as follows:

  • Masks are identified by indices running from 0 through 2 if no alpha is present, or 3 if an alpha is present.
  • The first three indices refer to color samples; index 0 corresponds to red, index 1 to green, and index 2 to blue.
  • Index 3 corresponds to the alpha sample, if present.

The translation from pixel values to color/alpha components for display or processing purposes is a one-to-one correspondence of samples to components. A DirectColorModel is typically used with image data which uses masks to define packed samples. For example, a DirectColorModel can be used in conjunction with a SinglePixelPackedSampleModel to construct a BufferedImage. Normally the masks used by the SampleModel and the ColorModel would be the same. However, if they are different, the color interpretation of pixel data will be done according to the masks of the ColorModel.

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 which use this representation will not throw an IllegalArgumentException due to an invalid pixel value.

This color model is similar to an X11 TrueColor visual. The default RGB ColorModel specified by the getRGBdefault method is a DirectColorModel with the following parameters: 

 Number of bits:        32
 Red mask:              0x00ff0000
 Green mask:            0x0000ff00
 Blue mask:             0x000000ff
 Alpha mask:            0xff000000
 Color space:           sRGB
 isAlphaPremultiplied:  False
 Transparency:          Transparency.TRANSLUCENT
 transferType:          DataBuffer.TYPE_INT

Many of the methods in this class are final. This is because 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 reasons, but you cannot override or modify the behavior of those methods.

See Also:
ColorModel, ColorSpace, SinglePixelPackedSampleModel, BufferedImage, ColorModel.getRGBdefault()

 

Field Summary

 
Fields inherited from class java.awt.image.ColorModel
pixel_bits, transferType
 
Fields inherited from interface java.awt.Transparency
BITMASK, OPAQUE, TRANSLUCENT
 

 

Constructor Summary

DirectColorModel(ColorSpace space, int bits, int rmask, int gmask, int bmask, int amask, boolean isAlphaPremultiplied, int transferType)
    Constructs a DirectColorModel from the specified parameters.
DirectColorModel(int bits, int rmask, int gmask, int bmask)
    Constructs a DirectColorModel from the specified masks that indicate which bits in an int pixel representation contain the red, green and blue color samples.
DirectColorModel(int bits, int rmask, int gmask, int bmask, int amask)
    Constructs a DirectColorModel from the specified masks that indicate which bits in an int pixel representation contain the red, green and blue color samples and the alpha sample, if present.
 

 

Method Summary

 ColorModel coerceData(WritableRaster raster, boolean isAlphaPremultiplied)
    Forces the raster data to match the state specified in the isAlphaPremultiplied variable, assuming the data is currently correctly described by this ColorModel.
 WritableRaster createCompatibleWritableRaster(int w, int h)
    Creates a WritableRaster with the specified width and height that has a data layout (SampleModel) compatible with this ColorModel.
 int getAlpha(int pixel)
    Returns the alpha component for the specified pixel, scaled from 0 to 255.
 int getAlpha(Object inData)
    Returns the alpha component for the specified pixel, scaled from 0 to 255.
 int getAlphaMask()
    Returns the mask indicating which bits in an int pixel representation contain the alpha component.
 int getBlue(int pixel)
    Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
 int getBlue(Object inData)
    Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
 int getBlueMask()
    Returns the mask indicating which bits in an int pixel representation contain the blue color component.
 int[] getComponents(int pixel, int[] components, int offset)
    Returns an array of unnormalized color/alpha components given a pixel in this ColorModel.
 int[] getComponents(Object pixel, int[] components, int offset)
    Returns an array of unnormalized color/alpha components given a pixel in this ColorModel.
 int getDataElement(int[] components, int offset)
    Returns a pixel value represented as an int in this ColorModel, given an array of unnormalized color/alpha components.
 Object getDataElements(int[] components, int offset, Object obj)
    Returns a data element array representation of a pixel in this ColorModel, given an array of unnormalized color/alpha components.
 Object getDataElements(int rgb, Object pixel)
    Returns a data element array representation of a pixel in this ColorModel, given an integer pixel representation in the default RGB color model.
 int getGreen(int pixel)
    Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
 int getGreen(Object inData)
    Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
 int getGreenMask()
    Returns the mask indicating which bits in an int pixel representation contain the green color component.
 int getRed(int pixel)
    Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
 int getRed(Object inData)
    Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
 int getRedMask()
    Returns the mask indicating which bits in an int pixel representation contain the red color component.
 int getRGB(int pixel)
    Returns the color/alpha components of the pixel in the default RGB color model format.
 int getRGB(Object inData)
    Returns the color/alpha components for the specified pixel in the default RGB color model format.
 boolean isCompatibleRaster(Raster raster)
    Returns true if raster is compatible with this ColorModel and false if it is not.
 String toString()
    Returns a String that represents this DirectColorModel.
 
Methods inherited from class java.awt.image.PackedColorModel
createCompatibleSampleModel, equals, getAlphaRaster, getMask, getMasks,