raster.java

JAVA基本类源代码,大家可以学习学习!

/*
 * @(#)Raster.java	1.59 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

/* ****************************************************************
 ******************************************************************
 ******************************************************************
 *** COPYRIGHT (c) Eastman Kodak Company, 1997
 *** As  an unpublished  work pursuant to Title 17 of the United
 *** States Code.  All rights reserved.
 ******************************************************************
 ******************************************************************
 ******************************************************************/


package java.awt.image;
import java.awt.Rectangle;
import java.awt.Point;

import sun.awt.image.ByteInterleavedRaster;
import sun.awt.image.ShortInterleavedRaster;
import sun.awt.image.IntegerInterleavedRaster;
import sun.awt.image.ByteBandedRaster;
import sun.awt.image.ShortBandedRaster;
import sun.awt.image.BytePackedRaster;
import sun.awt.image.SunWritableRaster;

/**
 * A class representing a rectangular array of pixels.  A Raster
 * encapsulates a DataBuffer that stores the sample values and a
 * SampleModel that describes how to locate a given sample value in a
 * DataBuffer.
 * <p>
 * A Raster defines values for pixels occupying a particular
 * rectangular area of the plane, not necessarily including (0, 0).
 * The rectangle, known as the Raster's bounding rectangle and
 * available by means of the getBounds method, is defined by minX,
 * minY, width, and height values.  The minX and minY values define
 * the coordinate of the upper left corner of the Raster.  References
 * to pixels outside of the bounding rectangle may result in an
 * exception being thrown, or may result in references to unintended
 * elements of the Raster's associated DataBuffer.  It is the user's
 * responsibility to avoid accessing such pixels.
 * <p>
 * A SampleModel describes how samples of a Raster
 * are stored in the primitive array elements of a DataBuffer.
 * Samples may be stored one per data element, as in a
 * PixelInterleavedSampleModel or BandedSampleModel, or packed several to
 * an element, as in a SinglePixelPackedSampleModel or
 * MultiPixelPackedSampleModel.  The SampleModel is also
 * controls whether samples are sign extended, allowing unsigned
 * data to be stored in signed Java data types such as byte, short, and
 * int.
 * <p>
 * Although a Raster may live anywhere in the plane, a SampleModel
 * makes use of a simple coordinate system that starts at (0, 0).  A
 * Raster therefore contains a translation factor that allows pixel
 * locations to be mapped between the Raster's coordinate system and
 * that of the SampleModel.  The translation from the SampleModel
 * coordinate system to that of the Raster may be obtained by the
 * getSampleModelTranslateX and getSampleModelTranslateY methods.
 * <p>
 * A Raster may share a DataBuffer with another Raster either by
 * explicit construction or by the use of the createChild and
 * createTranslatedChild methods.  Rasters created by these methods
 * can return a reference to the Raster they were created from by
 * means of the getParent method.  For a Raster that was not
 * constructed by means of a call to createTranslatedChild or
 * createChild, getParent will return null.
 * <p>
 * The createTranslatedChild method returns a new Raster that
 * shares all of the data of the current Raster, but occupies a
 * bounding rectangle of the same width and height but with a
 * different starting point.  For example, if the parent Raster
 * occupied the region (10, 10) to (100, 100), and the translated
 * Raster was defined to start at (50, 50), then pixel (20, 20) of the
 * parent and pixel (60, 60) of the child occupy the same location in
 * the DataBuffer shared by the two Rasters.  In the first case, (-10,
 * -10) should be added to a pixel coordinate to obtain the
 * corresponding SampleModel coordinate, and in the second case (-50,
 * -50) should be added.
 * <p>
 * The translation between a parent and child Raster may be
 * determined by subtracting the child's sampleModelTranslateX and
 * sampleModelTranslateY values from those of the parent.
 * <p>
 * The createChild method may be used to create a new Raster
 * occupying only a subset of its parent's bounding rectangle
 * (with the same or a translated coordinate system) or
 * with a subset of the bands of its parent.
 * <p>
 * All constructors are protected.  The correct way to create a
 * Raster is to use one of the static create methods defined in this
 * class.  These methods create instances of Raster that use the
 * standard Interleaved, Banded, and Packed SampleModels and that may
 * be processed more efficiently than a Raster created by combining
 * an externally generated SampleModel and DataBuffer.
 * @see java.awt.image.DataBuffer
 * @see java.awt.image.SampleModel
 * @see java.awt.image.PixelInterleavedSampleModel
 * @see java.awt.image.BandedSampleModel
 * @see java.awt.image.SinglePixelPackedSampleModel
 * @see java.awt.image.MultiPixelPackedSampleModel
 */
public class Raster {

    /**
     * The SampleModel that describes how pixels from this Raster
     * are stored in the DataBuffer.
     */
    protected SampleModel sampleModel;

    /** The DataBuffer that stores the image data. */
    protected DataBuffer dataBuffer;

    /** The X coordinate of the upper-left pixel of this Raster. */
    protected int minX;

    /** The Y coordinate of the upper-left pixel of this Raster. */
    protected int minY;

    /** The width of this Raster. */
    protected int width;

    /** The height of this Raster. */
    protected int height;

    /**
     * The X translation from the coordinate space of the
     * Raster's SampleModel to that of the Raster.
     */
    protected int sampleModelTranslateX;

    /**
     * The Y translation from the coordinate space of the
     * Raster's SampleModel to that of the Raster.
     */
    protected int sampleModelTranslateY;

    /** The number of bands in the Raster. */
    protected int numBands;

    /** The number of DataBuffer data elements per pixel. */
    protected int numDataElements;

    /** The parent of this Raster, or null. */
    protected Raster parent;

    static private native void initIDs();
    static {
        ColorModel.loadLibraries();
        initIDs();
    }

    /**
     * Creates a Raster based on a PixelInterleavedSampleModel with the
     * specified data type, width, height, and number of bands.
     *
     * <p> The upper left corner of the Raster is given by the
     * location argument.  If location is null, (0, 0) will be used.
     * The dataType parameter should be one of the enumerated values
     * defined in the DataBuffer class.
     *
     * <p> Note that interleaved <code>DataBuffer.TYPE_INT</code>
     * Rasters are not supported.  To create a 1-band Raster of type
     * <code>DataBuffer.TYPE_INT</code>, use
     * Raster.createPackedRaster().
     * <p> The only dataTypes supported currently are TYPE_BYTE
     * and TYPE_USHORT.
     * @param dataType  the data type for storing samples
     * @param w         the width in pixels of the image data
     * @param h         the height in pixels of the image data
     * @param bands     the number of bands
     * @param location  the upper-left corner of the <code>Raster</code>
     * @return a WritableRaster object with the specified data type,
     *         width, height and number of bands.
     * @throws RasterFormatException if <code>w</code> or <code>h</code>
     *         is less than or equal to zero, or computing either
     *         <code>location.x + w</code> or
     *         <code>location.y + h</code> results in integer
     *         overflow
     */
    public static WritableRaster createInterleavedRaster(int dataType,
                                                         int w, int h,
                                                         int bands,
                                                         Point location) {
        int[] bandOffsets = new int[bands];
        for (int i = 0; i < bands; i++) {
            bandOffsets[i] = i;
        }
        return createInterleavedRaster(dataType, w, h, w*bands, bands,
                                       bandOffsets, location);
    }

    /**
     * Creates a Raster based on a PixelInterleavedSampleModel with the
     * specified data type, width, height, scanline stride, pixel
     * stride, and band offsets.  The number of bands is inferred from
     * bandOffsets.length.
     *
     * <p> The upper left corner of the Raster is given by the
     * location argument.  If location is null, (0, 0) will be used.
     * The dataType parameter should be one of the enumerated values
     * defined in the DataBuffer class.
     *
     * <p> Note that interleaved <code>DataBuffer.TYPE_INT</code>
     * Rasters are not supported.  To create a 1-band Raster of type
     * <code>DataBuffer.TYPE_INT</code>, use
     * Raster.createPackedRaster().
     * <p> The only dataTypes supported currently are TYPE_BYTE
     * and TYPE_USHORT.
     * @param dataType  the data type for storing samples
     * @param w         the width in pixels of the image data
     * @param h         the height in pixels of the image data
     * @param scanlineStride the line stride of the image data
     * @param pixelStride the pixel stride of the image data
     * @param bandOffsets the offsets of all bands
     * @param location  the upper-left corner of the <code>Raster</code>
     * @return a WritableRaster object with the specified data type,
     *         width, height, scanline stride, pixel stride and band
     *         offsets.
     * @throws RasterFormatException if <code>w</code> or <code>h</code>
     *         is less than or equal to zero, or computing either
     *         <code>location.x + w</code> or
     *         <code>location.y + h</code> results in integer
     *         overflow
     * @throws IllegalArgumentException if <code>dataType</code> is not
     *         one of the supported data types, which are
     *         <code>DataBuffer.TYPE_BYTE</code>, or 
     *         <code>DataBuffer.TYPE_USHORT</code>.
     */
    public static WritableRaster createInterleavedRaster(int dataType,
                                                         int w, int h,
                                                         int scanlineStride,
                                                         int pixelStride,
                                                         int bandOffsets[],
                                                         Point location) {
	DataBuffer d;
        int bands = bandOffsets.length;

        int maxBandOff = bandOffsets[0];
        for (int i=1; i < bands; i++) {
            if (bandOffsets[i] > maxBandOff) {
                maxBandOff = bandOffsets[i];
            }
        }
        int size = maxBandOff + scanlineStride*(h-1) + pixelStride*(w-1) + 1;
        switch(dataType) {
        case DataBuffer.TYPE_BYTE:
            d = new DataBufferByte(size);
            break;

        case DataBuffer.TYPE_USHORT:
            d = new DataBufferUShort(size);
            break;

        default:
            throw new IllegalArgumentException("Unsupported data type " +
                                                dataType);
        }

        return createInterleavedRaster(d, w, h, scanlineStride,
                                       pixelStride, bandOffsets, location);
    }

    /**
     * Creates a Raster based on a BandedSampleModel with the
     * specified data type, width, height, and number of bands.
     *
     * <p> The upper left corner of the Raster is given by the
     * location argument.  If location is null, (0, 0) will be used.
     * The dataType parameter should be one of the enumerated values
     * defined in the DataBuffer class.
     *
     * <p> The only dataTypes supported currently are TYPE_BYTE, TYPE_USHORT,
     * and TYPE_INT.
     * @param dataType  the data type for storing samples
     * @param w         the width in pixels of the image data
     * @param h         the height in pixels of the image data
     * @param bands     the number of bands
     * @param location  the upper-left corner of the <code>Raster</code>
     * @return a WritableRaster object with the specified data type,
     *         width, height and number of bands.
     * @throws RasterFormatException if <code>w</code> or <code>h</code>
     *         is less than or equal to zero, or computing either
     *         <code>location.x + w</code> or
     *         <code>location.y + h</code> results in integer
     *         overflow
     * @throws ArrayIndexOutOfBoundsException if <code>bands</code>
     *         is less than 1