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 {@link BufferedImage}. Normally the masks used by the {@link 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 {@link ColorModel#getRGBdefault() 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 ColorModel
@see ColorSpace
@see SinglePixelPackedSampleModel
@see BufferedImage
@see ColorModel#getRGBdefault
@version 10 Feb 1997