directcolormodel.java

JAVA基本类源代码,大家可以学习学习!

/*
 * @(#)DirectColorModel.java	1.77 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.awt.image;

import java.awt.color.ColorSpace;
import java.awt.Transparency;

/**
 * The <code>DirectColorModel</code> class is a <code>ColorModel</code>
 * 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 <code>getMinValue()</code>
 * method of ColorSpace must be 0.0, and the maximum value obtained via
 * the <code>getMaxValue()</code> 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 <code>transferType</code>, 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:
 * <ul>
 * <li> Masks are identified by indices running from 0 through 2  
 * if no alpha is present, or 3 if an alpha is present.  
 * <li> The first three indices refer to color samples; 
 * index 0 corresponds to red, index 1 to green, and index 2 to blue.  
 * <li> Index 3 corresponds to the alpha sample, if present. 
 * </ul>
 * <p>
 * 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 <code>DirectColorModel</code> is 
 * typically used with image data which uses masks to define packed 
 * samples.  For example, a <code>DirectColorModel</code> can be used in
 * conjunction with a <code>SinglePixelPackedSampleModel</code> to 
 * construct a {@link BufferedImage}.  Normally the masks used by the 
 * {@link SampleModel} and the <code>ColorModel</code> would be the 
 * same.  However, if they are different, the color interpretation 
 * of pixel data will be done according to the masks of the 
 * <code>ColorModel</code>.
 * <p>
 * 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 <code>IllegalArgumentException</code>
 * due to an invalid pixel value.
 * <p>
 * This color model is similar to an X11 TrueColor visual.
 * The default RGB ColorModel specified by the 
 * {@link ColorModel#getRGBdefault() getRGBdefault} method is a 
 * <code>DirectColorModel</code> with the following parameters:
 * <pre>
 * 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
 * </pre>
 * <p>
 * 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
 */
public class DirectColorModel extends PackedColorModel {
    private int red_mask;
    private int green_mask;
    private int blue_mask;
    private int alpha_mask;
    private int red_offset;
    private int green_offset;
    private int blue_offset;
    private int alpha_offset;
    private int red_scale;
    private int green_scale;
    private int blue_scale;
    private int alpha_scale;
    private boolean is_LinearRGB;
    private int lRGBprecision;
    private byte[] tosRGB8LUT;
    private byte[] fromsRGB8LUT8;
    private short[] fromsRGB8LUT16;
    
    /**
     * Constructs a <code>DirectColorModel</code> from the specified masks 
     * that indicate which bits in an <code>int</code> pixel representation 
     * contain the red, green and blue color samples.  As pixel values do not
     * contain alpha information, all pixels are treated as opaque, which
     * means that alpha&nbsp;=&nbsp;1.0.  All of the bits
     * in each mask must be contiguous and fit in the specified number
     * of least significant bits of an <code>int</code> pixel representation.
     *  The <code>ColorSpace</code> is the default sRGB space. The
     * transparency value is Transparency.OPAQUE.  The transfer type
     * is the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
     * or DataBuffer.TYPE_INT that can hold a single pixel.
     * @param bits the number of bits in the pixel values; for example, 
     *         the sum of the number of bits in the masks.
     * @param rmask specifies a mask indicating which bits in an 
     *         integer pixel contain the red component
     * @param gmask specifies a mask indicating which bits in an
     *         integer pixel contain the green component
     * @param bmask specifies a mask indicating which bits in an
     *         integer pixel contain the blue component
     * 
     */
    public DirectColorModel(int bits,
			    int rmask, int gmask, int bmask) {
	this(bits, rmask, gmask, bmask, 0);
    }

    /**
     * Constructs a <code>DirectColorModel</code> from the specified masks 
     * that indicate which bits in an <code>int</code> pixel representation
     * contain the red, green and blue color samples and the alpha sample, 
     * if present.  If <code>amask</code> is 0, pixel values do not contain
     * alpha information and all pixels are treated as opaque, which means 
     * that alpha&nbsp;=&nbsp;1.0.  All of the bits in each mask must
     * be contiguous and fit in the specified number of least significant bits
     * of an <code>int</code> pixel representation.  Alpha, if present, is not
     * premultiplied.  The <code>ColorSpace</code> is the default sRGB space.
     * The transparency value is Transparency.OPAQUE if no alpha is
     * present, or Transparency.TRANSLUCENT otherwise.  The transfer type
     * is the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
     * or DataBuffer.TYPE_INT that can hold a single pixel.
     * @param bits the number of bits in the pixel values; for example, 
     *         the sum of the number of bits in the masks.
     * @param rmask specifies a mask indicating which bits in an
     *         integer pixel contain the red component
     * @param gmask specifies a mask indicating which bits in an
     *         integer pixel contain the green component
     * @param bmask specifies a mask indicating which bits in an
     *         integer pixel contain the blue component
     * @param amask specifies a mask indicating which bits in an
     *         integer pixel contain the alpha component
     */
    public DirectColorModel(int bits, int rmask, int gmask,
                            int bmask, int amask) {
        super (ColorSpace.getInstance(ColorSpace.CS_sRGB),
               bits, rmask, gmask, bmask, amask, false,
               amask == 0 ? Transparency.OPAQUE : Transparency.TRANSLUCENT,
               ColorModel.getDefaultTransferType(bits));
        setFields();
    }

    /**
     * Constructs a <code>DirectColorModel</code> from the specified
     * parameters.  Color components are in the specified 
     * <code>ColorSpace</code>, which must be of type ColorSpace.TYPE_RGB
     * and have minimum normalized component values which are all 0.0
     * and maximum values which are all 1.0.
     * The masks specify which bits in an <code>int</code> pixel 
     * representation contain the red, green and blue color samples and
     * the alpha sample, if present.  If <code>amask</code> is 0, pixel
     * values do not contain alpha information and all pixels are treated 
     * as opaque, which means that alpha&nbsp;=&nbsp;1.0.  All of the
     * bits in each mask must be contiguous and fit in the specified number
     * of least significant bits of an <code>int</code> pixel 
     * representation.  If there is alpha, the <code>boolean</code>
     * <code>isAlphaPremultiplied</code> specifies how to interpret
     * color and alpha samples in pixel values.  If the <code>boolean</code>
     * is <code>true</code>, color samples are assumed to have been
     * multiplied by the alpha sample.  The transparency value is
     * Transparency.OPAQUE, if no alpha is present, or
     * Transparency.TRANSLUCENT otherwise.  The transfer type
     * is the type of primitive array used to represent pixel values and
     * must be one of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or
     * DataBuffer.TYPE_INT.
     * @param space the specified <code>ColorSpace</code>
     * @param bits the number of bits in the pixel values; for example, 
     *         the sum of the number of bits in the masks.
     * @param rmask specifies a mask indicating which bits in an
     *         integer pixel contain the red component
     * @param gmask specifies a mask indicating which bits in an
     *         integer pixel contain the green component
     * @param bmask specifies a mask indicating which bits in an
     *         integer pixel contain the blue component
     * @param amask specifies a mask indicating which bits in an
     * 	       integer pixel contain the alpha component
     * @param isAlphaPremultiplied <code>true</code> if color samples are
     *        premultiplied by the alpha sample; <code>false</code> otherwise
     * @param transferType the type of array used to represent pixel values
     * @throws IllegalArgumentException if <code>space</code> is not a
     *         TYPE_RGB space or if the min/max normalized component
     *         values are not 0.0/1.0.
     */
    public DirectColorModel(ColorSpace space, int bits, int rmask,
                            int gmask, int bmask, int amask,
                            boolean isAlphaPremultiplied,
                            int transferType) {
        super (space, bits, rmask, gmask, bmask, amask,
               isAlphaPremultiplied,
               amask == 0 ? Transparency.OPAQUE : Transparency.TRANSLUCENT,
               transferType);  
        if (ColorModel.isLinearRGBspace(colorSpace)) {
            is_LinearRGB = true;
            if (maxBits <= 8) {
                lRGBprecision = 8;
                tosRGB8LUT = ColorModel.getLinearRGB8TosRGB8LUT();
                fromsRGB8LUT8 = ColorModel.getsRGB8ToLinearRGB8LUT();
            } else {
                lRGBprecision = 16;
                tosRGB8LUT = ColorModel.getLinearRGB16TosRGB8LUT();
                fromsRGB8LUT16 = ColorModel.getsRGB8ToLinearRGB16LUT();
            }
        } else if (!is_sRGB) {
            for (int i = 0; i < 3; i++) {
                // super constructor checks that space is TYPE_RGB
                // check here that min/max are all 0.0/1.0
                if ((space.getMinValue(i) != 0.0f) ||
                    (space.getMaxValue(i) != 1.0f)) {
                    throw new IllegalArgumentException(
                        "Illegal min/max RGB component value");
                }
            }
        }
        setFields();
    }

    /**
     * Returns the mask indicating which bits in an <code>int</code> pixel 
     * representation contain the red color component.
     * @return the mask, which indicates which bits of the <code>int</code> 
     *         pixel representation contain the red color sample. 
     */
    final public int getRedMask() {
	return maskArray[0];
    }

    /**
     * Returns the mask indicating which bits in an <code>int</code> pixel 
     * representation contain the green color component.
     * @return the mask, which indicates which bits of the <code>int</code> 
     *         pixel representation contain the green color sample. 
     */
    final public int getGreenMask() {
	return maskArray[1];
    }

    /**
     * Returns the mask indicating which bits in an <code>int</code> pixel 
     * representation contain the blue color component.
     * @return the mask, which indicates which bits of the <code>int</code> 
     *         pixel representation contain the blue color sample. 
     */
    final public int getBlueMask() {
	return maskArray[2];
    }

    /**
     * Returns the mask indicating which bits in an <code>int</code> pixel 
     * representation contain the alpha component.
     * @return the mask, which indicates which bits of the <code>int</code> 
     *         pixel representation contain the alpha sample. 
     */