gcc/libjava/classpath/java/awt/image/MultiPixelPackedSampleModel.java

/* Copyright (C) 2004  Free Software Foundation

This file is part of GNU Classpath.

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package java.awt.image;

import gnu.java.awt.Buffers;

/**
 * MultiPixelPackedSampleModel provides a single band model that supports
 * multiple pixels in a single unit.  Pixels have 2^n bits and 2^k pixels fit
 * per data element.
 *
 * @author Jerry Quinn (jlquinn@optonline.net)
 */
public class MultiPixelPackedSampleModel extends SampleModel
{
  private int scanlineStride;
  private int[] bitMasks;
  private int[] bitOffsets;
  private int[] sampleSize;
  private int dataBitOffset;
  private int elemBits;
  private int numberOfBits;
  private int numElems;

  public MultiPixelPackedSampleModel(int dataType, int w, int h,
				     int numberOfBits)
  {
    this(dataType, w, h, numberOfBits, 0, 0);
  }

  public MultiPixelPackedSampleModel(int dataType, int w, int h,
				     int numberOfBits, int scanlineStride,
				     int dataBitOffset)
  {
    super(dataType, w, h, 1);

    switch (dataType)
      {
      case DataBuffer.TYPE_BYTE:
	elemBits = 8;
	break;
      case DataBuffer.TYPE_USHORT:
	elemBits = 16;
	break;
      case DataBuffer.TYPE_INT:
	elemBits = 32;
	break;
      default:
	throw new IllegalArgumentException("MultiPixelPackedSampleModel"
					   + " unsupported dataType");
      }

    this.dataBitOffset = dataBitOffset;

    this.numberOfBits = numberOfBits;
    if (numberOfBits > elemBits)
      throw new RasterFormatException("MultiPixelPackedSampleModel pixel size"
				      + " larger than dataType");
    switch (numberOfBits)
      {
      case 1: case 2: case 4: case 8: case 16: case 32: break;
      default:
	throw new RasterFormatException("MultiPixelPackedSampleModel pixel"
					+ " size not 2^n bits");
      }
    numElems = elemBits / numberOfBits;

    // Compute scan line large enough for w pixels.
    if (scanlineStride == 0)
      scanlineStride = ((dataBitOffset + w * numberOfBits) / elemBits);
    this.scanlineStride = scanlineStride;

    
    sampleSize = new int[1];
    sampleSize[0] = numberOfBits;

    bitMasks = new int[numElems];
    bitOffsets = new int[numElems];
    for (int i=0; i < numElems; i++)
      {
	bitOffsets[numElems - i- 1] = numberOfBits * i;
	bitMasks[numElems - i - 1] = ((1 << numberOfBits) - 1) << 
	    bitOffsets[numElems - i - 1];
      }
  }

  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 MultiPixelPackedSampleModel(dataType, w, h, numberOfBits);
  }


  /**
   * 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.
   */
  public DataBuffer createDataBuffer()
  {
    int size;

    // FIXME:  The comment refers to SinglePixelPackedSampleModel.  See if the
    // same can be done for MultiPixelPackedSampleModel.
    // 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.
    size = scanlineStride * height;

    return Buffers.createBuffer(getDataType(), size);
  }


  public int getNumDataElements()
  {
    return 1;
  }

  public int[] getSampleSize()
  {
    return sampleSize;
  }
  
  public int getSampleSize(int band)
  {
    return sampleSize[0];
  }

  public int getOffset(int x, int y)
  {
    return scanlineStride * y + ((dataBitOffset + x*numberOfBits) / elemBits);
  }

  public int getBitOffset(int x)
  {
    return (dataBitOffset + x*numberOfBits) % elemBits;
  }

  public int getDataBitOffset()
  {
    return dataBitOffset;
  }

  public int getScanlineStride()
  {
    return scanlineStride;
  }

  public int getPixelBitStride()
  {
    return numberOfBits;
  }


  public SampleModel createSubsetSampleModel(int[] bands)
  {
    int numBands = bands.length;
    if (numBands != 1)
      throw new RasterFormatException("MultiPixelPackedSampleModel only"
				      + " supports one band");
    
    return new MultiPixelPackedSampleModel(dataType, width, height,
					   numberOfBits, scanlineStride,
					   dataBitOffset);
  }

  /**
   * Extract one pixel and return in an array of transfer type.
   *
   * Extracts the pixel at x, y from data and stores into the 0th index of the
   * array obj, since there is only one band.  If obj is null, a new array of
   * getTransferType() is created.
   *
   * @param x The x-coordinate of the pixel rectangle to store in <code>obj</code>.
   * @param y The y-coordinate of the pixel rectangle to store in <code>obj</code>.
   * @param obj The primitive array to store the pixels into or null to force creation.
   * @param data The DataBuffer that is the source of the pixel data.
   * @return The primitive array containing the pixel data.
   * @see java.awt.image.SampleModel#getDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer)
   */
  public Object getDataElements(int x, int y, Object obj,
				DataBuffer data)
  {
    int pixel = getSample(x, y, 0, data);
    switch (getTransferType())
    {
    case DataBuffer.TYPE_BYTE:
      if (obj == null) obj = new byte[1];
      ((byte[])obj)[0] = (byte)pixel;
      return obj;
    case DataBuffer.TYPE_USHORT:
      if (obj == null) obj = new short[1];
      ((short[])obj)[0] = (short)pixel;
      return obj;
    case DataBuffer.TYPE_INT:
      if (obj == null) obj = new int[1];
      ((int[])obj)[0] = pixel;
      return obj;
    default:
      // Seems like the only sensible thing to do.
      throw new ClassCastException();
    }
  }

  public int[] getPixel(int x, int y, int[] iArray, DataBuffer data)
  {
    if (iArray == null) iArray = new int[1];
    iArray[0] = getSample(x, y, 0, data);
	
    return iArray;
  }

  public int[] getPixels(int x, int y, int w, int h, int[] iArray,
			 DataBuffer data)
  {
    int offset = getOffset(x, y);
    if (iArray == null) iArray = new int[w*h];
    int outOffset = 0;
    for (y=0; y<h; y++)
      {
	int lineOffset = offset;
	for (x=0; x<w;)
	  {
	    int samples = data.getElem(lineOffset++);
	    for (int b=0; b<numElems && x<w; b++)
	      {
		iArray[outOffset++] = (samples & bitMasks[b]) >>> bitOffsets[b];
		x++;
	      }
	  }
	offset += scanlineStride;
      }
    return iArray;	
  }

  public int getSample(int x, int y, int b, DataBuffer data)
  {
    int pos =
      ((dataBitOffset + x * numberOfBits) % elemBits) / numberOfBits;
    int offset = getOffset(x, y);
    int samples = data.getElem(offset);
    return (samples & bitMasks[pos]) >>> bitOffsets[pos];
  }
  
  /**
   * Set the pixel at x, y to the value in the first element of the primitive
   * array obj.
   *
   * @param x The x-coordinate of the data elements in <code>obj</code>.
   * @param y The y-coordinate of the data elements in <code>obj</code>.
   * @param obj The primitive array containing the data elements to set.
   * @param data The DataBuffer to store the data elements into.
   * @see java.awt.image.SampleModel#setDataElements(int, int, int, int, java.lang.Object, java.awt.image.DataBuffer)
   */
  public void setDataElements(int x, int y, Object obj, DataBuffer data)
  {
    int transferType = getTransferType();
    if (getTransferType() != data.getDataType())
      {
	throw new IllegalArgumentException("transfer type ("+
					   getTransferType()+"), "+
					   "does not match data "+
					   "buffer type (" +
					   data.getDataType() +
					   ").");
      }

    int offset = getOffset(x, y);
    
    try
      {
	switch (transferType)
	  {
	  case DataBuffer.TYPE_BYTE:
	    {
	      DataBufferByte out = (DataBufferByte) data;
	      byte[] in = (byte[]) obj;
	      out.getData()[offset] = in[0];
	      return;
	    }
	  case DataBuffer.TYPE_USHORT:
	    {
	      DataBufferUShort out = (DataBufferUShort) data;
	      short[] in = (short[]) obj;
	      out.getData()[offset] = in[0];
	      return;
	    }
	  case DataBuffer.TYPE_INT:
	    {
	      DataBufferInt out = (DataBufferInt) data;
	      int[] in = (int[]) obj;
	      out.getData()[offset] = in[0];
	      return;
	    }
	  default:
	    throw new ClassCastException("Unsupported data type");
	  }
      }
    catch (ArrayIndexOutOfBoundsException aioobe)
      {
	String msg = "While writing data elements" +
	  ", x="+x+", y="+y+
	  ", width="+width+", height="+height+
	  ", scanlineStride="+scanlineStride+
	  ", offset="+offset+
	  ", data.getSize()="+data.getSize()+
	  ", data.getOffset()="+data.getOffset()+
	  ": " +
	  aioobe;
	throw new ArrayIndexOutOfBoundsException(msg);
      }
    }

  public void setPixel(int x, int y, int[] iArray, DataBuffer data)
  {
    setSample(x, y, 0, iArray[0], data);
  }

  public void setSample(int x, int y, int b, int s, DataBuffer data)
  {
    int bitpos =
      ((dataBitOffset + x * numberOfBits) % elemBits) / numberOfBits;
    int offset = getOffset(x, y);

    s = s << bitOffsets[bitpos];
    s = s & bitMasks[bitpos];

    int sample = data.getElem(offset);
    sample |= s;
    data.setElem(offset, sample);
  }
  
  /**
   * 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();
  }
}