singlepixelpackedsamplemodel.java

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/*
 * @(#)SinglePixelPackedSampleModel.java	1.41 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 *** As  an unpublished  work pursuant to Title 17 of the United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.util.Arrays;

/**
 *  This class represents pixel data packed such that the N samples which make
 *  up a single pixel are stored in a single data array element, and each data
 *  data array element holds samples for only one pixel.
 *  This class supports
 *  {@link DataBuffer#TYPE_BYTE TYPE_BYTE},
 *  {@link DataBuffer#TYPE_USHORT TYPE_USHORT},
 *  {@link DataBuffer#TYPE_INT TYPE_INT} data types.
 *  All data array elements reside
 *  in the first bank of a DataBuffer.  Accessor methods are provided so
 *  that the image data can be manipulated directly. Scanline stride is the
 *  number of data array elements between a given sample and the corresponding
 *  sample in the same column of the next scanline. Bit masks are the masks
 *  required to extract the samples representing the bands of the pixel.
 *  Bit offsets are the offsets in bits into the data array
 *  element of the samples representing the bands of the pixel.
 * <p>
 * The following code illustrates extracting the bits of the sample
 * representing band <code>b</code> for pixel <code>x,y</code>
 * from DataBuffer <code>data</code>:
 * <pre>
 *      int sample = data.getElem(y * scanlineStride + x);
 *      sample = (sample & bitMasks[b]) >>> bitOffsets[b];
 * </pre>
 */

public class SinglePixelPackedSampleModel extends SampleModel
{
    /** Bit masks for all bands of the image data. */
    private int bitMasks[];

    /** Bit Offsets for all bands of the image data. */
    private int bitOffsets[];

    /** Bit sizes for all the bands of the image data. */
    private int bitSizes[];

    /** Maximum bit size. */
    private int maxBitSize;

    /** Line stride of the region of image data described by this
     *  SinglePixelPackedSampleModel.
     */
    private int scanlineStride;

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

    /**
     * Constructs a SinglePixelPackedSampleModel with bitMasks.length bands.
     * Each sample is stored in a data array element in the position of
     * its corresponding bit mask.  Each bit mask must be contiguous and
     * masks must not overlap.
     * @param dataType 	The data type for storing samples.
     * @param w 	The width (in pixels) of the region of the
     *                  image data described.
     * @param h 	The height (in pixels) of the region of the
     *                  image data described.
     * @param bitMasks  The bit masks for all bands.
     * @throws IllegalArgumentException if <code>dataType</code> is not
     *         either <code>DataBuffer.TYPE_BYTE</code>,
     *         <code>DataBuffer.TYPE_USHORT</code>, or
     *         <code>DataBuffer.TYPE_INT</code>
     */
    public SinglePixelPackedSampleModel(int dataType, int w, int h,
				   int bitMasks[]) {
        this(dataType, w, h, w, bitMasks);
        if (dataType != DataBuffer.TYPE_BYTE &&
            dataType != DataBuffer.TYPE_USHORT &&
            dataType != DataBuffer.TYPE_INT) {
            throw new IllegalArgumentException("Unsupported data type "+
                                               dataType);
        }
    }

    /**
     * Constructs a SinglePixelPackedSampleModel with bitMasks.length bands
     * and a scanline stride equal to scanlineStride data array elements.
     * Each sample is stored in a data array element in the position of 
     * its corresponding bit mask.  Each bit mask must be contiguous and
     * masks must not overlap.
     * @param dataType 	The data type for storing samples.
     * @param w 	The width (in pixels) of the region of
     *                  image data described.
     * @param h 	The height (in pixels) of the region of
     *                  image data described.
     * @param scanlineStride The line stride of the image data.
     * @param bitMasks The bit masks for all bands.
     * @throws IllegalArgumentException if <code>w</code> or
     *         <code>h</code> is not greater than 0
     * @throws IllegalArgumentException if any mask in 
     *         <code>bitMask</code> is not contiguous
     * @throws IllegalArgumentException if <code>dataType</code> is not
     *         either <code>DataBuffer.TYPE_BYTE</code>,
     *         <code>DataBuffer.TYPE_USHORT</code>, or
     *         <code>DataBuffer.TYPE_INT</code>
     */
    public SinglePixelPackedSampleModel(int dataType, int w, int h,
                                   int scanlineStride, int bitMasks[]) {
        super(dataType, w, h, bitMasks.length);
        if (dataType != DataBuffer.TYPE_BYTE &&
            dataType != DataBuffer.TYPE_USHORT &&
            dataType != DataBuffer.TYPE_INT) {
            throw new IllegalArgumentException("Unsupported data type "+
                                               dataType);
        }
        this.dataType = dataType;
        this.bitMasks = (int[]) bitMasks.clone();
        this.scanlineStride = scanlineStride;

        this.bitOffsets = new int[numBands];
        this.bitSizes = new int[numBands];

        this.maxBitSize = 0;
        for (int i=0; i<numBands; i++) {
            int bitOffset = 0, bitSize = 0, mask;
            mask = bitMasks[i];

            if (mask != 0) {
                while ((mask & 1) == 0) {
                    mask = mask >>> 1;
                    bitOffset++;
                }
                while ((mask & 1) == 1) {
                    mask = mask >>> 1;
                    bitSize++;
                }
                if (mask != 0) {
                    throw new IllegalArgumentException("Mask "+bitMasks[i]+
                                                       " must be contiguous");
                }
            }
            bitOffsets[i] = bitOffset;
            bitSizes[i] = bitSize;
            if (bitSize > maxBitSize) {
                maxBitSize = bitSize;
            }
        }
    }

    /**
     * Returns the number of data elements needed to transfer one pixel
     * via the getDataElements and setDataElements methods.
     * For a SinglePixelPackedSampleModel, this is one.
     */
    public int getNumDataElements() {
	return 1;
    }

    /**
     * Returns the size of the buffer (in data array elements)
     * needed for a data buffer that matches this
     * SinglePixelPackedSampleModel.
     */
    private long getBufferSize() {
      long size = scanlineStride * (height-1) + width;
      return size;
    }

    /**
     * Creates a new SinglePixelPackedSampleModel with the specified
     * width and height.  The new SinglePixelPackedSampleModel will have the
     * same storage data type and bit masks as this
     * SinglePixelPackedSampleModel.  
     * @param w the width of the resulting <code>SampleModel</code>
     * @param h the height of the resulting <code>SampleModel</code>
     * @return a <code>SinglePixelPackedSampleModel</code> with the
     *         specified width and height.
     * @throws IllegalArgumentException if <code>w</code> or
     *         <code>h</code> is not greater than 0
     */
    public SampleModel createCompatibleSampleModel(int w, int h) {
      SampleModel sampleModel = new SinglePixelPackedSampleModel(dataType, w, h,
							      bitMasks);
      return sampleModel;
    }
    
    /** 
     * Creates a DataBuffer that corresponds to this
     * SinglePixelPackedSampleModel.  The DataBuffer's data type and size
     * will be consistent with this SinglePixelPackedSampleModel.  The
     * DataBuffer will have a single bank.
     */
    public DataBuffer createDataBuffer() {
	DataBuffer dataBuffer = null;

	int size = (int)getBufferSize();
	switch (dataType) {
	case DataBuffer.TYPE_BYTE:
	    dataBuffer = new DataBufferByte(size);
	    break;
	case DataBuffer.TYPE_USHORT:
	    dataBuffer = new DataBufferUShort(size);
	    break;
	case DataBuffer.TYPE_INT:
	    dataBuffer = new DataBufferInt(size);
	    break;
	}
	return dataBuffer;
    }

    /** Returns the number of bits per sample for all bands. */
    public int[] getSampleSize() {
	int mask;
	int sampleSize[] = new int [numBands];
	for (int i=0; i<numBands; i++) {
	    sampleSize[i] = 0;
	    mask = bitMasks[i] >>> bitOffsets[i];
	    while ((mask & 1) != 0) {
		sampleSize[i] ++;
		mask = mask >>> 1;
	    }
	}

	return sampleSize;
    }

    /** Returns the number of bits per sample for the specified band. */
    public int getSampleSize(int band) {
	int sampleSize = 0;
	int mask = bitMasks[band] >>> bitOffsets[band];
	while ((mask & 1) != 0) {
	    sampleSize ++;
	    mask = mask >>> 1;
	}

	return sampleSize;
    }

    /** Returns the offset (in data array elements) of pixel (x,y).
     *  The data element containing pixel <code>x,y</code>
     *  can be retrieved from a DataBuffer <code>data</code> with a
     *  SinglePixelPackedSampleModel <code>sppsm</code> as:
     * <pre>
     *        data.getElem(sppsm.getOffset(x, y));
     * </pre>
     * @param x,&nbsp;y the coordinates of the specified pixel
     * @return the offset of the specified pixel.
     */
    public int getOffset(int x, int y) {
	int offset = y * scanlineStride + x;
	return offset;
    }

    /** Returns the bit offsets into the data array element representing
     *  a pixel for all bands. 
     *  @return the bit offsets representing a pixel for all bands.     
     */
    public int [] getBitOffsets() {
      return (int[])bitOffsets.clone();
    }

    /** Returns the bit masks for all bands. 
     *  @return the bit masks for all bands.
     */
    public int [] getBitMasks() {
      return (int[])bitMasks.clone();
    }

    /** Returns the scanline stride of this SinglePixelPackedSampleModel. 
     *  @return the scanline stride of this 
     *          <code>SinglePixelPackedSampleModel</code>.
     */
    public int getScanlineStride() {
      return scanlineStride;
    }

    /**
     * This creates a new SinglePixelPackedSampleModel with a subset of the
     * bands of this SinglePixelPackedSampleModel.  The new
     * SinglePixelPackedSampleModel can be used with any DataBuffer that the
     * existing SinglePixelPackedSampleModel can be used with.  The new
     * SinglePixelPackedSampleModel/DataBuffer combination will represent
     * an image with a subset of the bands of the original
     * SinglePixelPackedSampleModel/DataBuffer combination.
     * @exception RasterFormatException if the length of the bands argument is
     *                                  greater than the number of bands in
     *                                  the sample model.
     */
    public SampleModel createSubsetSampleModel(int bands[]) {
	if (bands.length > numBands)
	    throw new RasterFormatException("There are only " +
					    numBands +
					    " bands");
	int newBitMasks[] = new int[bands.length];
	for (int i=0; i<bands.length; i++)
	    newBitMasks[i] = bitMasks[bands[i]];

        return new SinglePixelPackedSampleModel(this.dataType, width, height,
					   this.scanlineStride, newBitMasks);
    }

    /** 
     * Returns data for a single pixel in a primitive array of type
     * TransferType.  For a SinglePixelPackedSampleModel, the array will
     * have one element, and the type will be the same as the storage
     * data type.  Generally, obj
     * should be passed in as null, so that the Object will be created
     * automatically and will be of the right primitive data type.
     * <p>
     * The following code illustrates transferring data for one pixel from
     * DataBuffer <code>db1</code>, whose storage layout is described by
     * SinglePixelPackedSampleModel <code>sppsm1</code>, to
     * DataBuffer <code>db2</code>, whose storage layout is described by
     * SinglePixelPackedSampleModel <code>sppsm2</code>.
     * The transfer will generally be more efficient than using
     * getPixel/setPixel.
     * <pre>
     * 	     SinglePixelPackedSampleModel sppsm1, sppsm2;
     *	     DataBufferInt db1, db2;
     * 	     sppsm2.setDataElements(x, y, sppsm1.getDataElements(x, y, null,
     *                              db1), db2);
     * </pre>
     * Using getDataElements/setDataElements to transfer between two
     * DataBuffer/SampleModel pairs is legitimate if the SampleModels have
     * the same number of bands, corresponding bands have the same number of
     * bits per sample, and the TransferTypes are the same.
     * <p>
     * If obj is non-null, it should be a primitive array of type TransferType.
     * Otherwise, a ClassCastException is thrown.  An
     * ArrayIndexOutOfBoundsException may be thrown if the coordinates are
     * not in bounds, or if obj is non-null and is not large enough to hold
     * the pixel data.
     * @param x 	The X coordinate of the pixel location.
     * @param y 	The Y coordinate of the pixel location.
     * @param obj       If non-null, a primitive array in which to return
     *                  the pixel data.
     * @param data      The DataBuffer containing the image data.
     * @return the data for the specified pixel.
     * @see #setDataElements(int, int, Object, DataBuffer)
     */
    public Object getDataElements(int x, int y, Object obj, DataBuffer data) {
        // Bounds check for 'b' will be performed automatically
        if ((x < 0) || (y < 0) || (x >= width) || (y >= height)) {
            throw new ArrayIndexOutOfBoundsException
                ("Coordinate out of bounds!");
        }

	int type = getTransferType();

	switch(type) {

	case DataBuffer.TYPE_BYTE:

	    byte[] bdata;

	    if (obj == null)
		bdata = new byte[1];
	    else
		bdata = (byte[])obj;

	    bdata[0] = (byte)data.getElem(y * scanlineStride + x);

	    obj = (Object)bdata;
	    break;

	case DataBuffer.TYPE_USHORT:

	    short[] sdata;

	    if (obj == null)
		sdata = new short[1];
	    else
		sdata = (short[])obj;

	    sdata[0] = (short)data.getElem(y * scanlineStride + x);

	    obj = (Object)sdata;
	    break;