indexcolormodel.java

来自「Mac OS X 10.4.9 for x86 Source Code gcc」· Java 代码 · 共 517 行 · 第 1/2 页

        && transferType != DataBuffer.TYPE_USHORT)
      throw new IllegalArgumentException();
    if (bits > 16)
      throw new IllegalArgumentException("bits > 16");
    if (size < 1)
      throw new IllegalArgumentException("size < 1");
    map_size = size;
    opaque = !hasAlpha;
    this.trans = trans;

    rgb = new int[size];
    if (!hasAlpha)
      for (int i = 0; i < size; i++)
	rgb[i] = cmap[i + start] | 0xff000000;
    else
      System.arraycopy(cmap, start, rgb, 0, size);

    // Generate a bigint with 1's for every pixel
    validBits = validBits.setBit(size).subtract(BigInteger.ONE);
  }

  /**
   * Construct an IndexColorModel using a colormap with holes.
   * 
   * The IndexColorModel is built from the array of ints defining the
   * colormap.  Each element contains red, green, blue, and alpha
   * components.    The ColorSpace is sRGB.  The transparency value is
   * automatically determined.
   * 
   * This constructor permits indicating which colormap entries are valid,
   * using the validBits argument.  Each entry in cmap is valid if the
   * corresponding bit in validBits is set.  
   * 
   * @param bits the number of bits needed to represent <code>size</code> colors
   * @param size the number of colors in the color map
   * @param cmap packed color components
   * @param start the offset of the first color component in <code>cmap</code>
   * @param transferType DataBuffer.TYPE_BYTE or DataBuffer.TYPE_USHORT
   * @throws IllegalArgumentException if bits < 1, bits > 16, or size < 1.
   * @throws IllegalArgumentException if transferType is something other than
   * TYPE_BYTE or TYPE_USHORT.
   */
  public IndexColorModel (int bits, int size, int[] cmap, int start, 
                          int transferType, BigInteger validBits)
  {
    super(bits * 4, // total bits, sRGB, four channels
	  nArray(bits, 4), // bits for each channel
	  ColorSpace.getInstance(ColorSpace.CS_sRGB), // sRGB
	  true, // has alpha
	  false, // not premultiplied
	  TRANSLUCENT, transferType);
    if (transferType != DataBuffer.TYPE_BYTE
        && transferType != DataBuffer.TYPE_USHORT)
      throw new IllegalArgumentException();
    if (bits > 16)
      throw new IllegalArgumentException("bits > 16");
    if (size < 1)
      throw new IllegalArgumentException("size < 1");
    map_size = size;
    opaque = false;
    this.trans = -1;
    this.validBits = validBits;

    rgb = new int[size];
    if (!hasAlpha)
      for (int i = 0; i < size; i++)
	rgb[i] = cmap[i + start] | 0xff000000;
    else
      System.arraycopy(cmap, start, rgb, 0, size);
  }

  public final int getMapSize ()
  {
    return map_size;
  }

  /**
   * Get the index of the transparent color in this color model
   */
  public final int getTransparentPixel ()
  {
    return trans;
  }

  /**
   * <br>
   */
  public final void getReds (byte[] r)
  {
    getComponents (r, 2);
  }

  /**
   * <br>
   */
  public final void getGreens (byte[] g)
  {
    getComponents (g, 1);
  }

  /**
   * <br>
   */
  public final void getBlues (byte[] b)
  {
    getComponents (b, 0);
  }

  /**
   * <br>
   */
  public final void getAlphas (byte[] a)
  {
    getComponents (a, 3);
  }

  private void getComponents (byte[] c, int ci)
  {
    int i, max = (map_size < c.length) ? map_size : c.length;
    for (i = 0; i < max; i++)
	    c[i] = (byte) ((generateMask (ci)  & rgb[i]) >> (ci * pixel_bits));
  } 

  /**
   * Get the red component of the given pixel.
   */
  public final int getRed (int pixel)
  {
    if (pixel < map_size)
	    return (int) ((generateMask (2) & rgb[pixel]) >> (2 * pixel_bits));
    
    return 0;
  }

  /**
   * Get the green component of the given pixel.
   */
  public final int getGreen (int pixel)
  {
    if (pixel < map_size)
	    return (int) ((generateMask (1) & rgb[pixel]) >> (1 * pixel_bits));
    
    return 0;
  }

  /**
   * Get the blue component of the given pixel.
   */
  public final int getBlue (int pixel)
  {
    if (pixel < map_size) 
	    return (int) (generateMask (0) & rgb[pixel]);
    
    return 0;
  }

  /**
   * Get the alpha component of the given pixel.
   */
  public final int getAlpha (int pixel)
  {
    if (opaque || pixel >= map_size)
      return 255;

    return (int) ((generateMask (3) & rgb[pixel]) >> (3 * pixel_bits));
  }

  /**
   * Get the RGB color value of the given pixel using the default
   * RGB color model. 
   *
   * @param pixel a pixel value
   */
  public final int getRGB (int pixel)
  {
    if (pixel < map_size)
	    return rgb[pixel];
    
    return 0;
  }
    
  /**
   * Get the RGB color values of all pixels in the map using the default
   * RGB color model. 
   *
   * @param rgb The destination array.
   */
  public final void getRGBs (int[] rgb)
  {
    System.arraycopy(this.rgb, 0, rgb, 0, map_size);
  }
    
   //pixel_bits is number of bits to be in generated mask
  private int generateMask (int offset)
  {
    return (((2 << pixel_bits ) - 1) << (pixel_bits * offset));
  }

  /** Return true if pixel is valid, false otherwise. */
  public boolean isValid(int pixel)
  {
    return validBits.testBit(pixel);
  }
  
  /** Return true if all pixels are valid, false otherwise. */
  public boolean isValid()
  {
    // Generate a bigint with 1's for every pixel
    BigInteger allbits = new BigInteger("0");
    allbits.setBit(map_size);
    allbits.subtract(new BigInteger("1"));
    return allbits.equals(validBits);
  }
  
  /** 
   * Returns a BigInteger where each bit represents an entry in the color
   * model.  If the bit is on, the entry is valid.
   */
  public BigInteger getValidPixels()
  {
    return validBits;
  }
  
  /**
   * Construct a BufferedImage with rgb pixel values from a Raster.
   * 
   * Constructs a new BufferedImage in which each pixel is an RGBA int from
   * a Raster with index-valued pixels.  If this model has no alpha component
   * or transparent pixel, the type of the new BufferedImage is TYPE_INT_RGB.
   * Otherwise the type is TYPE_INT_ARGB.  If forceARGB is true, the type is
   * forced to be TYPE_INT_ARGB no matter what.
   * 
   * @param raster The source of pixel values.
   * @param forceARGB True if type must be TYPE_INT_ARGB.
   * @return New BufferedImage with RBGA int pixel values.
   */
  public BufferedImage convertToIntDiscrete(Raster raster, boolean forceARGB)
  {
    int type = forceARGB ? BufferedImage.TYPE_INT_ARGB
      : ((opaque && trans == -1) ? BufferedImage.TYPE_INT_RGB :
	 BufferedImage.TYPE_INT_ARGB); 

    // FIXME: assuming that raster has only 1 band since pixels are supposed
    // to be int indexes.
    // FIXME: it would likely be more efficient to fetch a complete array,
    // but it would take much more memory.
    // FIXME: I'm not sure if transparent pixels or alpha values need special
    // handling here.
    BufferedImage im = new BufferedImage(raster.width, raster.height, type);
    for (int x = raster.minX; x < raster.width + raster.minX; x++)
      for (int y = raster.minY; y < raster.height + raster.minY; y++)
        im.setRGB(x, y, rgb[raster.getSample(x, y, 0)]);

    return im;
  }
}