colormodel.java

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/* Copyright (C) 1999, 2000, 2002  Free Software Foundation

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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package java.awt.image;

import java.awt.Point;
import java.awt.Transparency;
import java.awt.color.ColorSpace;
import gnu.java.awt.Buffers;

/**
 * A color model operates with colors in several formats:
 *
 * <ul>
 * <li>normalized: component samples are in range [0.0, 1.0].</li>
 *
 * <li>color model pixel value: all the color component samples for a
 * sigle pixel packed/encoded in a way natural for the color
 * model.</li>
 *
 * <li>color model pixel int value: only makes sense if the natural
 * encoding of a single pixel can fit in a single int value.</li>
 *
 * <li>array of transferType containing a single pixel: the pixel is
 * encoded in the natural way of the color model, taking up as many
 * array elements as needed.</li>
 *
 * <li>sRGB pixel int value: a pixel in sRGB color space, encoded in
 * default 0xAARRGGBB format, assumed not alpha premultiplied.</li>
 * 
 * <li>single [0, 255] scaled int samples from default sRGB color
 * space. These are always assumed to be alpha non-premultiplied.</li>
 *
 * <li>arrays of unnormalized component samples of single pixel: these
 * samples are scaled and multiplied according to the color model, but
 * is otherwise not packed or encoded. Each element of the array is one
 * separate component sample. The color model only operate on the
 * components from one pixel at a time, but using offsets, allows
 * manipulation of arrays that contain the components of more than one
 * pixel.</li>
 *
 * </ul>
 *
 * @author Rolf W. Rasmussen <[e-mail]>
 * @author C. Brian Jones ([e-mail]) 
 */
public abstract class ColorModel implements Transparency
{
  protected int pixel_bits;
  protected int transferType;

  int[] bits;
  ColorSpace cspace;
  int transparency;
  boolean hasAlpha;
  boolean isAlphaPremultiplied;
    
  static int[] nArray(int value, int times)
  {
    int[] array = new int[times];
    java.util.Arrays.fill(array, value);
    return array;
  }

  static byte[] nArray(byte value, int times)
  {
    byte[] array = new byte[times];
    java.util.Arrays.fill(array, value);
    return array;
  } 

  /**
   * Constructs the default color model.  The default color model 
   * can be obtained by calling <code>getRGBdefault</code> of this
   * class.
   * @param b the number of bits wide used for bit size of pixel values
   */
  public ColorModel(int bits)
  {
    this(bits * 4, // total bits, sRGB, four channels
	 nArray(bits, 4), // bits for each channel
	 null, // FIXME: should be sRGB
	 true, // has alpha
	 false, // not premultiplied
	 TRANSLUCENT,
	 Buffers.smallestAppropriateTransferType(bits * 4));
  }

  /**
   * Constructs a ColorModel that translates pixel values to
   * color/alpha components.
   *
   * @exception IllegalArgumentException If the length of the bit array is less
   * than the number of color or alpha components in this ColorModel, or if the
   * transparency is not a valid value, or if the sum of the number of bits in
   * bits is less than 1 or if any of the elements in bits is less than 0.
   */
  protected ColorModel(int pixel_bits, int[] bits, ColorSpace cspace,
		       boolean hasAlpha, boolean isAlphaPremultiplied,
		       int transparency, int transferType)
  {
    int bits_sum = 0;
    for (int i = 0; i < bits.length; i++)
      {
        if (bits [i] < 0)
          throw new IllegalArgumentException ();

        bits_sum |= bits [i];
      }
    
    if ((bits.length < cspace.numComponents)
        || (bits_sum < 1))
      throw new IllegalArgumentException ();

    this.pixel_bits = pixel_bits;
    this.bits = bits;
    this.cspace = cspace;
    this.hasAlpha = hasAlpha;
    this.isAlphaPremultiplied = isAlphaPremultiplied;
    this.transparency = transparency;
    this.transferType = transferType;
  }

  /**
   * Returns the default color model which in Sun's case is an instance
   * of <code>DirectColorModel</code>.
   */
  public static ColorModel getRGBdefault()
  {
    return new DirectColorModel(8, 0xff0000, 0xff00, 0xff, 0xff000000);
  }

  public final boolean hasAlpha()
  {
    return hasAlpha;
  }

  public final boolean isAlphaPremultiplied()
  {
    return isAlphaPremultiplied;
  }

  /**
   * Get get number of bits wide used for the bit size of pixel values
   */
  public int getPixelSize()
  {
    return pixel_bits;
  }
    
  public int getComponentSize(int componentIdx)
  {
    return bits[componentIdx];
  }
    
  public int[] getComponentSize()
  {
    return bits;
  }

  public int getTransparency()
  {
    return transparency;
  }

  public int getNumComponents()
  {
    return getNumColorComponents() + (hasAlpha ? 1 : 0);
  }

  public int getNumColorComponents()
  {
    return cspace.getNumComponents();
  }

  /**
   * Converts pixel value to sRGB and extract red int sample scaled
   * to range [0, 255].
   *
   * @param pixel pixel value that will be interpreted according to
   * the color model, (assumed alpha premultiplied if color model says
   * so.)
   *
   * @return red sample scaled to range [0, 255], from default color
   * space sRGB, alpha non-premultiplied.
   */
  public abstract int getRed(int pixel);

  /**
   * Converts pixel value to sRGB and extract green int sample
   * scaled to range [0, 255].
   *
   * @see #getRed(int)
   */
    public abstract int getGreen(int pixel);
    
  /**
   * Converts pixel value to sRGB and extract blue int sample
   * scaled to range [0, 255].
   *
   * @see #getRed(int)
   */
  public abstract int getBlue(int pixel);

  /**
   * Extract alpha int sample from pixel value, scaled to [0, 255].
   *
   * @param pixel pixel value that will be interpreted according to
   * the color model.
   *
   * @return alpha sample, scaled to range [0, 255].
   */
  public abstract int getAlpha(int pixel);

  /**
   * Converts a pixel int value of the color space of the color
   * model to a sRGB pixel int value.
   *
   * This method is typically overriden in subclasses to provide a
   * more efficient implementation.
   * 
   * @param pixel pixel value that will be interpreted according to
   * the color model.
   *
   * @return a pixel in sRGB color space, encoded in default
   * 0xAARRGGBB format.  */
  public int getRGB(int pixel)
  {
    return 
      ((getAlpha(pixel) & 0xff) << 24) |
      ((  getRed(pixel) & 0xff) << 16) |
      ((getGreen(pixel) & 0xff) <<  8) |
      (( getBlue(pixel) & 0xff) <<  0);
  }
  

  /**
   * In this color model we know that the whole pixel value will
   * always be contained within the first element of the pixel
   * array.
   */
  final int getPixelFromArray(Object inData) {
    DataBuffer data =
      Buffers.createBufferFromData(transferType, inData, 1);
    Object da = Buffers.getData(data);

    return data.getElem(0);
  }

  /** 
   * Converts pixel in the given array to sRGB and extract blue int
   * sample scaled to range [0-255].
   *
   * This method is typically overriden in subclasses to provide a
   * more efficient implementation.
   * 
   * @param array of transferType containing a single pixel.  The
   * pixel should be encoded in the natural way of the color model.
   */
  public int getRed(Object inData)
  {
    return getRed(getPixelFromArray(inData));
  }

  /**
   * @see #getRed(Object)
   */
  public int getGreen(Object inData)
  {
    return getGreen(getPixelFromArray(inData));
  }

  /**
   * @see #getRed(Object)
   */
  public int getBlue(Object inData) {
    return getBlue(getPixelFromArray(inData));
  }

  /**
   * @see #getRed(Object)
   */
  public int getAlpha(Object inData) {
    return getAlpha(getPixelFromArray(inData));
  }

  /**