SinglePixelPackedSampleModel.java

/* Copyright (C) 2000, 2002, 2003, 2004, 2006,  Free Software Foundation

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package java.awt.image;

import java.util.Arrays;

import gnu.java.awt.BitMaskExtent;

/**
 * A <code>SampleModel</code> used when all samples are stored in a single
 * data element in the {@link DataBuffer}, and each data element contains 
 * samples for one pixel only.
 * 
 * @author Rolf W. Rasmussen (rolfwr@ii.uib.no)
 */
public class SinglePixelPackedSampleModel extends SampleModel
{
  private int scanlineStride;
  private int[] bitMasks;
  private int[] bitOffsets;
  private int[] sampleSize;
  
  /**
   * Creates a new <code>SinglePixelPackedSampleModel</code>.
   * 
   * @param dataType  the data buffer type.
   * @param w  the width (in pixels).
   * @param h  the height (in pixels).
   * @param bitMasks  an array containing the bit mask used to extract the
   *     sample value for each band.
   */
  public SinglePixelPackedSampleModel(int dataType, int w, int h,
				      int[] bitMasks)
  {
    this(dataType, w, h, w, bitMasks);
  }

  /**
   * Creates a new <code>SinglePixelPackedSampleModel</code>.
   * 
   * @param dataType  the data buffer type.
   * @param w  the width (in pixels).
   * @param h  the height (in pixels).
   * @param scanlineStride  the number of data elements between a pixel on one
   *     row and the corresponding pixel on the next row.
   * @param bitMasks  an array containing the bit mask used to extract the
   *     sample value for each band.
   */
  public SinglePixelPackedSampleModel(int dataType, int w, int h,
				      int scanlineStride, int[] bitMasks)
  {
    super(dataType, w, h, bitMasks.length);

    switch (dataType)
      {
      case DataBuffer.TYPE_BYTE:
      case DataBuffer.TYPE_USHORT:
      case DataBuffer.TYPE_INT:
	break;
      default:
        throw new IllegalArgumentException(
            "SinglePixelPackedSampleModel unsupported dataType");
      }
    
    this.scanlineStride = scanlineStride;
    this.bitMasks = bitMasks;
    
    bitOffsets = new int[numBands];
    sampleSize = new int[numBands];
    
    BitMaskExtent extent = new BitMaskExtent();
    for (int b = 0; b < numBands; b++)
      {
        // the mask is an unsigned integer
        long mask = bitMasks[b] & 0xFFFFFFFFL;
        extent.setMask(mask);
        sampleSize[b] = extent.bitWidth;
        bitOffsets[b] = extent.leastSignificantBit;
      }
  }

  /**
   * Returns the number of data elements.
   * 
   * @return <code>1</code>.
   */
  public int getNumDataElements()
  {
    return 1;
  }

  /**
   * Creates a new <code>SampleModel</code> that is compatible with this
   * model and has the specified width and height.
   * 
   * @param w  the width (in pixels).
   * @param h  the height (in pixels).
   * 
   * @return The new sample model.
   */
  public SampleModel createCompatibleSampleModel(int w, int h)
  {
    /* FIXME: We can avoid recalculation of bit offsets and sample
       sizes here by passing these from the current instance to a
       special private constructor. */
    return new SinglePixelPackedSampleModel(dataType, w, h, bitMasks);
  }


  /**
   * Creates a DataBuffer for holding pixel data in the format and
   * layout described by this SampleModel. The returned buffer will
   * consist of one single bank.
   * 
   * @return The data buffer.
   */
  public DataBuffer createDataBuffer()
  {
    // We can save (scanlineStride - width) pixels at the very end of
    // the buffer. The Sun reference implementation (J2SE 1.3.1 and
    // 1.4.1_01) seems to do this; tested with Mauve test code.
    int size = scanlineStride * (height - 1) + width;

    DataBuffer buffer = null;
    switch (getTransferType())
      {
      case DataBuffer.TYPE_BYTE:
        buffer = new DataBufferByte(size);
        break;
      case DataBuffer.TYPE_USHORT:
        buffer = new DataBufferUShort(size);
        break;
      case DataBuffer.TYPE_INT:
        buffer = new DataBufferInt(size);
        break;
      }
    return buffer;
  }

  /**
   * Returns an array containing the size (in bits) for each band accessed by
   * the <code>SampleModel</code>.
   * 
   * @return An array.
   * 
   * @see #getSampleSize(int)
   */
  public int[] getSampleSize()
  {
    return (int[]) sampleSize.clone();
  }
  
  /**
   * Returns the size (in bits) of the samples for the specified band.
   * 
   * @param band  the band (in the range <code>0</code> to 
   *     <code>getNumBands() - 1</code>).
   *     
   * @return The sample size (in bits).
   */
  public int getSampleSize(int band)
  {
    return sampleSize[band];
  }

  /**
   * Returns the index in the data buffer that stores the pixel at (x, y).
   * 
   * @param x  the x-coordinate.
   * @param y  the y-coordinate.
   * 
   * @return The index in the data buffer that stores the pixel at (x, y).
   */
  public int getOffset(int x, int y)
  {
    return scanlineStride*y + x;
  }

  public int[] getBitOffsets()
  {
    return bitOffsets;
  }

  public int[] getBitMasks()
  {
    return bitMasks;
  }

  /**
   * Returns the number of data elements from a pixel in one row to the
   * corresponding pixel in the next row.
   * 
   * @return The scanline stride.
   */
  public int getScanlineStride()
  {
    return scanlineStride;
  }

  /**
   * Creates a new <code>SinglePixelPackedSampleModel</code> that accesses
   * the specified subset of bands.
   * 
   * @param bands  an array containing band indices (<code>null</code> not
   *     permitted).
   * 
   * @return A new sample model.
   * 
   * @throws NullPointerException if <code>bands</code> is <code>null</code>.
   * @throws RasterFormatException if <code>bands.length</code> is greater
   *     than the number of bands in this model.
   */
  public SampleModel createSubsetSampleModel(int[] bands)
  {
    if (bands.length > numBands)
      throw new RasterFormatException("Too many bands.");
    
    int numBands = bands.length;
    
    int[] bitMasks = new int[numBands];

    for (int b = 0; b < numBands; b++)
      bitMasks[b] = this.bitMasks[bands[b]];

    return new SinglePixelPackedSampleModel(dataType, width, height,
					    scanlineStride, bitMasks);
  }

  public Object getDataElements(int x, int y, Object obj,
				DataBuffer data)
  {
    int type = getTransferType();
    Object ret = null;
    switch (type)
      {
      case DataBuffer.TYPE_BYTE:
        {
          byte[] in = (byte[]) obj;
          if (in == null)
            in = new byte[1];
          in[0] = (byte) data.getElem(x + y * scanlineStride);
          ret = in;
        }
        break;
      case DataBuffer.TYPE_USHORT:
        {
          short[] in = (short[]) obj;
          if (in == null)
            in = new short[1];
          in[0] = (short) data.getElem(x + y * scanlineStride);
          ret = in;
        }
        break;
      case DataBuffer.TYPE_INT:
        {
          int[] in = (int[]) obj;
          if (in == null)
            in = new int[1];
          in[0] = data.getElem(x + y * scanlineStride);
          ret = in;
        }
        break;
      }
    return ret;
  }
  
  /**
   * Returns an array containing the samples for the pixel at (x, y) in the
   * specified data buffer.  If <code>iArray</code> is not <code>null</code>,
   * it will be populated with the sample values and returned as the result of
   * this function (this avoids allocating a new array instance).
   * 
   * @param x  the x-coordinate of the pixel.
   * @param y  the y-coordinate of the pixel.
   * @param iArray  an array to populate with the sample values and return as 
   *     the result (if <code>null</code>, a new array will be allocated).
   * @param data  the data buffer (<code>null</code> not permitted).
   * 
   * @return The pixel sample values.
   * 
   * @throws NullPointerException if <code>data</code> is <code>null</code>.
   */
  public int[] getPixel(int x, int y, int[] iArray, DataBuffer data)
  {
    int offset = scanlineStride*y + x;
    if (iArray == null) iArray = new int[numBands];
    int samples = data.getElem(offset);

    for (int b = 0; b < numBands; b++)
      iArray[b] = (samples & bitMasks[b]) >>> bitOffsets[b];
	
    return iArray;
  }

  /**
   * Returns an array containing the samples for the pixels in the region 
   * specified by (x, y, w, h) in the specified data buffer.  The array is
   * ordered by pixels (that is, all the samples for the first pixel are 
   * grouped together, followed by all the samples for the second pixel, and so
   * on).  If <code>iArray</code> is not <code>null</code>, it will be 
   * populated with the sample values and returned as the result of this 
   * function (this avoids allocating a new array instance).
   * 
   * @param x  the x-coordinate of the top-left pixel.
   * @param y  the y-coordinate of the top-left pixel.
   * @param w  the width of the region of pixels.
   * @param h  the height of the region of pixels.
   * @param iArray  an array to populate with the sample values and return as 
   *     the result (if <code>null</code>, a new array will be allocated).
   * @param data  the data buffer (<code>null</code> not permitted).
   * 
   * @return The pixel sample values.
   * 
   * @throws NullPointerException if <code>data</code> is <code>null</code>.
   */
  public int[] getPixels(int x, int y, int w, int h, int[] iArray,
			 DataBuffer data)
  {
    int offset = scanlineStride*y + x;
    if (iArray == null) iArray = new int[numBands*w*h];
    int outOffset = 0;
    for (y = 0; y < h; y++)
      {
	int lineOffset = offset;
	for (x = 0; x < w; x++)
	  {
	    int samples = data.getElem(lineOffset++);
	    for (int b = 0; b < numBands; b++)
	      iArray[outOffset++] = (samples & bitMasks[b]) >>> bitOffsets[b];
	  }
	offset += scanlineStride;
      }
    return iArray;	
  }

  /**
   * Returns the sample value for the pixel at (x, y) in the specified data 
   * buffer.
   * 
   * @param x  the x-coordinate of the pixel.
   * @param y  the y-coordinate of the pixel.
   * @param b  the band (in the range <code>0</code> to 
   *     <code>getNumBands() - 1</code>).
   * @param data  the data buffer (<code>null</code> not permitted).
   * 
   * @return The sample value.
   * 
   * @throws NullPointerException if <code>data</code> is <code>null</code>.
   */
  public int getSample(int x, int y, int b, DataBuffer data)
  {
    int offset = scanlineStride*y + x;
    int samples = data.getElem(offset);
    return (samples & bitMasks[b]) >>> bitOffsets[b];
  }
  
  public void setDataElements(int x, int y, Object obj, DataBuffer data)
  {
    int transferType = getTransferType();
    switch (transferType)
      {
      case DataBuffer.TYPE_BYTE:
        {
          byte[] in = (byte[]) obj;
          data.setElem(y * scanlineStride + x, ((int) in[0]) & 0xff);
        }
        break;
      case DataBuffer.TYPE_USHORT:
        {
          short[] in = (short[]) obj;
          data.setElem(y * scanlineStride + x, ((int) in[0]) & 0xffff);
        }
        break;
      case DataBuffer.TYPE_INT:
        {
          int[] in = (int[]) obj;
          data.setElem(y * scanlineStride + x, in[0]);
          break;
        }
      }
  }

  /**
   * Sets the samples for the pixel at (x, y) in the specified data buffer to
   * the specified values. 
   * 
   * @param x  the x-coordinate of the pixel.
   * @param y  the y-coordinate of the pixel.
   * @param iArray  the sample values (<code>null</code> not permitted).
   * @param data  the data buffer (<code>null</code> not permitted).
   * 
   * @throws NullPointerException if either <code>iArray</code> or 
   *     <code>data</code> is <code>null</code>.
   */
  public void setPixel(int x, int y, int[] iArray, DataBuffer data)
  {
    int offset = scanlineStride*y + x;
    
    int samples = 0;
    for (int b = 0; b < numBands; b++)
      samples |= (iArray[b] << bitOffsets[b]) & bitMasks[b];

    data.setElem(offset, samples);
  }

  /**
   * This method implements a more efficient way to set pixels than the default
   * implementation of the super class. It copies the pixel components directly
   * from the input array instead of creating a intermediate buffer.
   * @param x The x-coordinate of the pixel rectangle in <code>obj</code>.
   * @param y The y-coordinate of the pixel rectangle in <code>obj</code>.
   * @param w The width of the pixel rectangle in <code>obj</code>.
   * @param h The height of the pixel rectangle in <code>obj</code>.
   * @param iArray The primitive array containing the pixels to set.
   * @param data The DataBuffer to store the pixels into.
   * @see java.awt.image.SampleModel#setPixels(int, int, int, int, int[], 
   *     java.awt.image.DataBuffer)
   */
  public void setPixels(int x, int y, int w, int h, int[] iArray,
						DataBuffer data)
  {
    int inOffset = 0;
    for (int yy=y; yy<(y+h); yy++)
     {
      int offset = scanlineStride*yy + x;
      for (int xx=x; xx<(x+w); xx++)
       { 
        int samples = 0;
        for (int b = 0; b < numBands; b++)
          samples |= (iArray[inOffset+b] << bitOffsets[b]) & bitMasks[b];
        data.setElem(0, offset, samples);
        inOffset += numBands;
        offset += 1;
      }
    }
  }
  
  /**
   * Sets the sample value for a band for the pixel at (x, y) in the 
   * specified data buffer. 
   * 
   * @param x  the x-coordinate of the pixel.
   * @param y  the y-coordinate of the pixel.
   * @param b  the band (in the range <code>0</code> to 
   *     <code>getNumBands() - 1</code>).
   * @param s  the sample value.
   * @param data  the data buffer (<code>null</code> not permitted).
   * 
   * @throws NullPointerException if <code>data</code> is <code>null</code>.
   */
  public void setSample(int x, int y, int b, int s, DataBuffer data)
  {
    int offset = scanlineStride*y + x;
    int samples = data.getElem(offset);
    int bitMask = bitMasks[b];
    samples &= ~bitMask;
    samples |= (s << bitOffsets[b]) & bitMask;
    data.setElem(offset, samples);
  }
  
  /**
   * Tests this sample model for equality with an arbitrary object.  This 
   * method returns <code>true</code> if and only if:
   * <ul>
   *   <li><code>obj</code> is not <code>null</code>;
   *   <li><code>obj</code> is an instance of 
   *       <code>SinglePixelPackedSampleModel</code>;
   *   <li>both models have the same:
   *     <ul>
   *       <li><code>dataType</code>;
   *       <li><code>width</code>;
   *       <li><code>height</code>;
   *       <li><code>numBands</code>;
   *       <li><code>scanlineStride</code>;
   *       <li><code>bitMasks</code>;
   *       <li><code>bitOffsets</code>.
   *     </ul>
   *   </li>
   * </ul>
   * 
   * @param obj  the object (<code>null</code> permitted)
   * 
   * @return <code>true</code> if this model is equal to <code>obj</code>, and
   *     <code>false</code> otherwise.
   */
  public boolean equals(Object obj) 
  {
    if (this == obj) 
      return true;
    if (! (obj instanceof SinglePixelPackedSampleModel)) 
      return false;
    SinglePixelPackedSampleModel that = (SinglePixelPackedSampleModel) obj;
    if (this.dataType != that.dataType)
      return false;
    if (this.width != that.width)
      return false;
    if (this.height != that.height)
      return false;
    if (this.numBands != that.numBands)
      return false;
    if (this.scanlineStride != that.scanlineStride)
      return false;
    if (!Arrays.equals(this.bitMasks, that.bitMasks))
      return false;
    if (!Arrays.equals(this.bitOffsets, that.bitOffsets)) 
      return false;
    return true;
  }
  
  /**
   * Returns a hash code for this <code>SinglePixelPackedSampleModel</code>.
   * 
   * @return A hash code.
   */
  public int hashCode()
  {
    // this hash code won't match Sun's, but that shouldn't matter...
    int result = 193;
    result = 37 * result + dataType;
    result = 37 * result + width;
    result = 37 * result + height;
    result = 37 * result + numBands;
    result = 37 * result + scanlineStride;
    for (int i = 0; i < bitMasks.length; i++)
      result = 37 * result + bitMasks[i];
    for (int i = 0; i < bitOffsets.length; i++)
      result = 37 * result + bitOffsets[i];
    return result;
  }
  
  /**
   * Creates a String with some information about this SampleModel.
   * @return A String describing this SampleModel.
   * @see java.lang.Object#toString()
   */
  public String toString()
  {
    StringBuffer result = new StringBuffer();
    result.append(getClass().getName());
    result.append("[");
    result.append("scanlineStride=").append(scanlineStride);
    for(int i = 0; i < bitMasks.length; i+=1)
    {
      result.append(", mask[").append(i).append("]=0x").append(
          Integer.toHexString(bitMasks[i]));
    }
    
    result.append("]");
    return result.toString();
  }
}