path: root/libjava/classpath/java/awt/image/DirectColorModel.java

/* DirectColorModel.java --
   Copyright (C) 1999, 2000, 2002, 2004  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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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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independent module, the terms and conditions of the license of that
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package java.awt.image;

import gnu.java.awt.Buffers;

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

/**
 * @author Rolf W. Rasmussen (rolfwr@ii.uib.no)
 * @author C. Brian Jones (cbj@gnu.org)
 * @author Mark Benvenuto (mcb54@columbia.edu)
 */
public class DirectColorModel extends PackedColorModel
{
  /**
   * For the color model created with this constructor the pixels
   * will have fully opaque alpha components with a value of 255.
   * Each mask should describe a fully contiguous set of bits in the
   * most likely order of alpha, red, green, blue from the most significant
   * byte to the least significant byte.
   *
   * @param pixelBits the number of bits wide used for bit size of pixel values
   * @param rmask the bits describing the red component of a pixel
   * @param gmask the bits describing the green component of a pixel
   * @param bmask the bits describing the blue component of a pixel
   */
  public DirectColorModel(int pixelBits, int rmask, int gmask, int bmask)
  {
    this(ColorSpace.getInstance(ColorSpace.CS_sRGB), pixelBits,
         rmask, gmask, bmask, 0,
         false, // not alpha premultiplied
         Buffers.smallestAppropriateTransferType(pixelBits) // find type
         );
  }

  /**
   * For the color model created with this constructor the pixels
   * will have fully opaque alpha components with a value of 255.
   * Each mask should describe a fully contiguous set of bits in the
   * most likely order of red, green, blue from the most significant
   * byte to the least significant byte.
   *
   * @param pixelBits the number of bits wide used for bit size of pixel values
   * @param rmask the bits describing the red component of a pixel
   * @param gmask the bits describing the green component of a pixel
   * @param bmask the bits describing the blue component of a pixel
   * @param amask the bits describing the alpha component of a pixel
   */
  public DirectColorModel(int pixelBits,
                          int rmask, int gmask, int bmask, int amask)
  {
    this(ColorSpace.getInstance(ColorSpace.CS_sRGB), pixelBits,
         rmask, gmask, bmask, amask,
         false, // not alpha premultiplied
         Buffers.smallestAppropriateTransferType(pixelBits) // find type
         );
  }

  public DirectColorModel(ColorSpace cspace, int pixelBits,
                          int rmask, int gmask, int bmask, int amask,
                          boolean isAlphaPremultiplied,
                          int transferType)
  {
    super(cspace, pixelBits,
          rmask, gmask, bmask, amask, isAlphaPremultiplied,
          ((amask == 0) ? Transparency.OPAQUE : Transparency.TRANSLUCENT),
          transferType);
  }

  public final int getRedMask()
  {
    return getMask(0);
  }

  public final int getGreenMask()
  {
    return getMask(1);
  }

  public final int getBlueMask()
  {
    return getMask(2);
  }

  public final int getAlphaMask()
  {
    return hasAlpha() ? getMask(3) : 0;
  }

  /**
   * Get the red component of the given pixel.
   * <br>
   */
  public final int getRed(int pixel)
  {
    return extractAndNormalizeSample(pixel, 0);
  }

  /**
   * Get the green component of the given pixel.
   * <br>
   */
  public final int getGreen(int pixel)
  {
    return extractAndNormalizeSample(pixel, 1);
  }

  /**
   * Get the blue component of the given pixel.
   * <br>
   */
  public final int getBlue(int pixel)
  {
    return extractAndNormalizeSample(pixel, 2);
  }

  /**
   * Get the alpha component of the given pixel.
   * <br>
   */
  public final int getAlpha(int pixel)
  {
    if (!hasAlpha())
      return 255;
    return extractAndScaleSample(pixel, 3);
  }

  private int extractAndNormalizeSample(int pixel, int component)
  {
    int value = extractAndScaleSample(pixel, component);
    if (hasAlpha() && isAlphaPremultiplied() && getAlpha(pixel) != 0)
      value = value*255/getAlpha(pixel);
    return value;
  }

  private int extractAndScaleSample(int pixel, int component)
  {
    int field = pixel & getMask(component);
    int to8BitShift =
      8 - shifts[component] - getComponentSize(component);
    return (to8BitShift>0) ?
      (field << to8BitShift) :
      (field >>> (-to8BitShift));
  }

  /**
   * Get the RGB color value of the given pixel using the default
   * RGB color model.
   * <br>
   *
   * @param pixel a pixel value
   */
  public final int getRGB(int pixel)
  {
    /* FIXME: The Sun docs show that this method is overridden, but I
       don't see any way to improve on the superclass
       implementation. */
    return super.getRGB(pixel);
  }

  public int getRed(Object inData)
  {
    return getRed(getPixelFromArray(inData));
  }

  public int getGreen(Object inData)
  {
    return getGreen(getPixelFromArray(inData));
  }

  public int getBlue(Object inData)
  {
    return getBlue(getPixelFromArray(inData));
  }

  public int getAlpha(Object inData)
  {
    return getAlpha(getPixelFromArray(inData));
  }

  public int getRGB(Object inData)
  {
    return getRGB(getPixelFromArray(inData));
  }

  /**
   * Converts a normalized pixel int value in the sRGB color
   * space to an array containing a single pixel of the color space
   * of the color model.
   *
   * <p>This method performs the inverse function of
   * <code>getRGB(Object inData)</code>.
   *
   * @param rgb pixel as a normalized sRGB, 0xAARRGGBB value.
   *
   * @param pixel to avoid needless creation of arrays, an array to
   * use to return the pixel can be given. If null, a suitable array
   * will be created.
   *
   * @return array of transferType containing a single pixel. The
   * pixel should be encoded in the natural way of the color model.
   *
   * @see #getRGB(Object)
   */
  public Object getDataElements(int rgb, Object pixel)
  {
    // FIXME: handle alpha multiply

    int pixelValue = 0;
    int a = 0;
    if (hasAlpha()) {
      a = (rgb >>> 24) & 0xff;
      pixelValue = valueToField(a, 3, 8);
    }

    if (hasAlpha() && isAlphaPremultiplied())
      {
        int r, g, b;
        /* if r=0xff and a=0xff, then resulting
           value will be (r*a)>>>8 == 0xfe... This seems wrong.
           We should divide by 255 rather than shifting >>>8 after
           multiplying.

           Too bad, shifting is probably less expensive.
           r = ((rgb >>> 16) & 0xff)*a;
           g = ((rgb >>>  8) & 0xff)*a;
           b = ((rgb >>> 0) & 0xff)*a; */
        /* The r, g, b values we calculate are 16 bit. This allows
           us to avoid discarding the lower 8 bits obtained if
           multiplying with the alpha band. */

        // using 16 bit values
        r = ((rgb >>> 8) & 0xff00)*a/255;
        g = ((rgb >>> 0) & 0xff00)*a/255;
        b = ((rgb <<  8) & 0xff00)*a/255;
        pixelValue |=
          valueToField(r, 0, 16) |  // Red
          valueToField(g, 1, 16) |  // Green
          valueToField(b, 2, 16);   // Blue
      }
    else
      {
        int r, g, b;
        // using 8 bit values
        r = (rgb >>> 16) & 0xff;
        g = (rgb >>>  8) & 0xff;
        b = (rgb >>>  0) & 0xff;

        pixelValue |=
          valueToField(r, 0, 8) |  // Red
          valueToField(g, 1, 8) |  // Green
          valueToField(b, 2, 8);   // Blue
      }

    /* In this color model, the whole pixel fits in the first element
       of the array. */
    DataBuffer buffer = Buffers.createBuffer(transferType, pixel, 1);
    buffer.setElem(0, pixelValue);
    return Buffers.getData(buffer);
  }

  /**
   * Converts a value to the correct field bits based on the
   * information derived from the field masks.
   *
   * @param highBit the position of the most significant bit in the
   * val parameter.
   */
  private int valueToField(int val, int component, int highBit)
  {
    int toFieldShift =
      getComponentSize(component) + shifts[component] - highBit;
    int ret = (toFieldShift>0) ?
      (val << toFieldShift) :
      (val >>> (-toFieldShift));
    return ret & getMask(component);
  }

  /**
   * Converts a 16 bit value to the correct field bits based on the
   * information derived from the field masks.
   */
  private int value16ToField(int val, int component)
  {
    int toFieldShift = getComponentSize(component) + shifts[component] - 16;
    return (toFieldShift>0) ?
      (val << toFieldShift) :
      (val >>> (-toFieldShift));
  }

  /**
   * Fills an array with the unnormalized component samples from a
   * pixel value. I.e. decompose the pixel, but not perform any
   * color conversion.
   */
  public final int[] getComponents(int pixel, int[] components, int offset)
  {
    int numComponents = getNumComponents();
    if (components == null) components = new int[offset + numComponents];

    for (int b=0; b<numComponents; b++)
      components[offset++] = (pixel&getMask(b)) >>> shifts[b];

    return components;
  }

  public final int[] getComponents(Object pixel, int[] components,
                                   int offset)
  {
    return getComponents(getPixelFromArray(pixel), components, offset);
  }

  /**
   * Creates a <code>WriteableRaster</code> that has a <code>SampleModel</code>
   * that is compatible with this <code>ColorModel</code>.
   *
   * @param w the width of the writeable raster to create
   * @param h the height of the writeable raster to create
   *
   * @throws IllegalArgumentException if <code>w</code> or <code>h</code>
   *         is less than or equal to zero
   */
  public final WritableRaster createCompatibleWritableRaster(int w, int h)
  {
    // Sun also makes this check here.
    if(w <= 0 || h <= 0)
      throw new IllegalArgumentException("width (=" + w + ") and height (="
                                         + h + ") must be > 0");

    SampleModel sm = createCompatibleSampleModel(w, h);
    Point origin = new Point(0, 0);
    return Raster.createWritableRaster(sm, origin);
  }

  public int getDataElement(int[] components, int offset)
  {
    int numComponents = getNumComponents();
    int pixelValue = 0;

    for (int c=0; c<numComponents; c++)
      pixelValue |= (components[offset++] << shifts[c]) & getMask(c);

    return pixelValue;
  }

  public Object getDataElements(int[] components, int offset, Object obj)
  {
    /* In this color model, the whole pixel fits in the first element
       of the array. */
    int pixelValue = getDataElement(components, offset);

    DataBuffer buffer = Buffers.createBuffer(transferType, obj, 1);
    buffer.setElem(0, pixelValue);
    return Buffers.getData(buffer);
  }

  public final ColorModel coerceData (WritableRaster raster,
                                      boolean isAlphaPremultiplied)
  {
    if (this.isAlphaPremultiplied == isAlphaPremultiplied || !hasAlpha())
      return this;

    /* TODO: provide better implementation based on the
       assumptions we can make due to the specific type of the
       color model. */
    coerceDataWorker(raster, isAlphaPremultiplied);

    return new DirectColorModel(cspace, pixel_bits, getRedMask(),
                                getGreenMask(), getBlueMask(), getAlphaMask(),
                                isAlphaPremultiplied, transferType);
  }

  public boolean isCompatibleRaster(Raster raster)
  {
    /* FIXME: the Sun docs say this method is overridden here,
       but I don't see any way to improve upon the implementation
       in ColorModel. */
    return super.isCompatibleRaster(raster);
  }

  String stringParam()
  {
    return super.stringParam() +
      ", redMask=" + Integer.toHexString(getRedMask()) +
      ", greenMask=" + Integer.toHexString(getGreenMask()) +
      ", blueMask=" + Integer.toHexString(getBlueMask()) +
      ", alphaMask=" + Integer.toHexString(getAlphaMask());
  }

  public String toString()
  {
    /* FIXME: Again, docs say override, but how do we improve upon the
       superclass implementation? */
    return super.toString();
  }
}