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/* ColorModel.java --

   Copyright (C) 1999, 2000, 2002, 2003, 2004, 2006  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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02110-1301 USA.

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permission to link this library with independent modules to produce an

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independent module, the terms and conditions of the license of that

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this exception to your version of the library, but you are not

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exception statement from your version. */

package java.awt.image;

import gnu.java.awt.Buffers;

import java.awt.Point;

import java.awt.Transparency;

import java.awt.color.ColorSpace;

import java.util.Arrays;

/**

 * 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 (rolfwr@ii.uib.no)

 * @author C. Brian Jones (cbj@gnu.org)

 */

public abstract class ColorModel implements Transparency

{

  protected int pixel_bits;

  protected int transferType;

  int[] bits;

  ColorSpace cspace;

  int transparency;

  boolean hasAlpha;

  boolean isAlphaPremultiplied;

  /**

   * The standard color model for the common sRGB.

   */

  private static final ColorModel S_RGB_MODEL = new SRGBColorModel();

  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 bits 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

         ColorSpace.getInstance(ColorSpace.CS_sRGB), // 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.getNumComponents())

        || (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;

  }

  public void finalize()

  {

    // Do nothing here.

  }

  /**

   * Returns the default color model which in Sun's case is an instance

   * of <code>DirectColorModel</code>.

   */

  public static ColorModel getRGBdefault()

  {

    return S_RGB_MODEL;

  }

  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 inData 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));

  }

  /**

   * Converts a pixel in the given array of the color space of the

   * color model to an sRGB pixel int value.

   *

   * <p>This method performs the inverse function of

   * <code>getDataElements(int rgb, Object pixel)</code>.

   * I.e. <code>(rgb == cm.getRGB(cm.getDataElements(rgb,

   * null)))</code>.

   *

   * @param inData array of transferType containing a single pixel. The

   * pixel should be encoded in the natural way of the color model.

   *

   * @return a pixel in sRGB color space, encoded in default

   * 0xAARRGGBB format.

   *

   * @see #getDataElements(int, Object)

   */

  public int getRGB(Object inData)

  {

    return

      ((getAlpha(inData) & 0xff) << 24) |

      ((  getRed(inData) & 0xff) << 16) |

      ((getGreen(inData) & 0xff) <<  8) |

      (( getBlue(inData) & 0xff) <<  0);

  }

  /**

   * Converts an sRGB pixel int value 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>.

   *

   * Outline of conversion process:

   *

   * <ol>

   *

   * <li>Convert rgb to normalized [0.0, 1.0] sRGB values.</li>

   *

   * <li>Convert to color space components using fromRGB in

   * ColorSpace.</li>

   *

   * <li>If color model has alpha and should be premultiplied,

   * multiply color space components with alpha value</li>

   *

   * <li>Scale the components to the correct number of bits.</li>

   *

   * <li>Arrange the components in the output array</li>

   *

   * </ol>

   *

   * @param rgb The color to be converted to dataElements.  A pixel

   * in sRGB color space, encoded in default 0xAARRGGBB format,

   * assumed not alpha premultiplied.

   *

   * @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 An array of transferType values representing the color,

   * in the color model format. The color model defines whether the

   *

   * @see #getRGB(Object)

   */

  public Object getDataElements(int rgb, Object pixel)

  {

    // subclasses has to implement this method.

    throw new UnsupportedOperationException();

  }

  /**

   * Fills an array with the unnormalized component samples from a

   * pixel value. I.e. decompose the pixel, but not perform any

   * color conversion.

   *

   * This method is typically overriden in subclasses to provide a

   * more efficient implementation.

   *

   * @param pixel pixel value encoded according to the color model.

   *

   * @return arrays of unnormalized component samples of single

   * pixel.  The scale and multiplication state of the samples are

   * according to the color model. Each component sample is stored

   * as a separate element in the array.

   */

  public int[] getComponents(int pixel, int[] components, int offset)

  {

    // subclasses has to implement this method.

    throw new UnsupportedOperationException();

  }

  /**

   * Fills an array with the unnormalized component samples from an

   * array of transferType containing a single pixel. I.e. decompose

   * the pixel, but not perform any color conversion.

   *

   * This method is typically overriden in subclasses to provide a

   * more efficient implementation.

   *

   * @param pixel an array of transferType containing a single pixel.  The

   * pixel should be encoded in the natural way of the color model.  If

   * this argument is not an array, as expected, a {@link ClassCastException}

   * will be thrown.

   * @param components an array that will be filled with the color component

   * of the pixel.  If this is null, a new array will be allocated

   * @param offset index into the components array at which the result

   * will be stored

   *

   * @return arrays of unnormalized component samples of single

   * pixel.  The scale and multiplication state of the samples are

   * according to the color model. Each component sample is stored

   * as a separate element in the array.

   */

  public int[] getComponents(Object pixel, int[] components, int offset)

  {

    // subclasses has to implement this method.

    throw new UnsupportedOperationException();

  }

  /**

   * Convert normalized components to unnormalized components.

   */

  public int[] getUnnormalizedComponents(float[] normComponents,

                                         int normOffset,

                                         int[] components,

                                         int offset)

  {

    int numComponents = getNumComponents();

    if (components == null)

    {

      components = new int[offset + numComponents];

    }

    for (int i=0; i<numComponents; i++)

    {

      float in = normComponents[normOffset++];

      int out = (int) (in * ((1<<getComponentSize(i)) - 1));

      components[offset++] = out;

    }

    return components;

  }

  /**

   * Convert unnormalized components to normalized components.

   */

  public float[] getNormalizedComponents(int[] components,

                                         int offset,

                                         float[] normComponents,

                                         int normOffset)

  {

    int numComponents = getNumComponents();

    if (normComponents == null)

    {

      normComponents = new float[normOffset + numComponents];

    }

    for (int i=0; i<numComponents; i++)

    {

      float in = components[offset++];

      float out = in / ((1<<getComponentSize(i)) - 1);

      normComponents[normOffset++] = out;

    }

    return normComponents;

  }

  /**

   * Convert unnormalized components to normalized components.

   *

   * @since 1.4

   */

  public float[] getNormalizedComponents (Object pixel,

                                          float[] normComponents,

                                          int normOffset)

  {

    int[] components = getComponents(pixel, null, 0);

    return getNormalizedComponents(components, 0, normComponents, normOffset);

  }

  /**

   * Converts the unnormalized component samples from an array to a

   * pixel value. I.e. composes the pixel from component samples, but

   * does not perform any color conversion or scaling of the samples.

   *

   * This method performs the inverse function of

   * <code>getComponents(int pixel, int[] components,

   *                           int offset)</code>. I.e.

   *

   * <code>(pixel == cm.getDataElement(cm.getComponents(pixel, null,

   * 0), 0))</code>.

   *

   * This method is overriden in subclasses since this abstract class throws

   * UnsupportedOperationException().

   *

   * @param components Array of unnormalized component samples of single

   * pixel.  The scale and multiplication state of the samples are according

   * to the color model. Each component sample is stored as a separate element

   * in the array.

   * @param offset Position of the first value of the pixel in components.

   *

   * @return pixel value encoded according to the color model.

   */

  public int getDataElement(int[] components, int offset)

  {

    // subclasses have to implement this method.

    throw new UnsupportedOperationException();

  }

  /**

   * Converts the normalized component samples from an array to a pixel

   * value. I.e. composes the pixel from component samples, but does not

   * perform any color conversion or scaling of the samples.

   *

   * This method is typically overriden in subclasses to provide a

   * more efficient implementation.  The method provided by this abstract

   * class converts the components to unnormalized form and returns

   * getDataElement(int[], int).

   *

   * @param components Array of normalized component samples of single pixel.

   * The scale and multiplication state of the samples are according to the

   * color model. Each component sample is stored as a separate element in the

   * array.

   * @param offset Position of the first value of the pixel in components.

   *

   * @return pixel value encoded according to the color model.

   * @since 1.4

   */

  public int getDataElement (float[] components, int offset)

  {

    return

      getDataElement(getUnnormalizedComponents(components, offset, null, 0),

                     0);

  }

  public Object getDataElements(int[] components, int offset, Object obj)

  {

    // subclasses have to implement this method.

    throw new UnsupportedOperationException();

  }

  /**

   * Converts the normalized component samples from an array to an array of

   * TransferType values. I.e. composes the pixel from component samples, but

   * does not perform any color conversion or scaling of the samples.

   *

   * If obj is null, a new array of TransferType is allocated and returned.

   * Otherwise the results are stored in obj and obj is returned.  If obj is

   * not long enough, ArrayIndexOutOfBounds is thrown.  If obj is not an array

   * of primitives, ClassCastException is thrown.

   *

   * This method is typically overriden in subclasses to provide a

   * more efficient implementation.  The method provided by this abstract

   * class converts the components to unnormalized form and returns

   * getDataElement(int[], int, Object).

   *

   * @param components Array of normalized component samples of single pixel.

   * The scale and multiplication state of the samples are according to the

   * color model. Each component sample is stored as a separate element in the

   * array.

   * @param offset Position of the first value of the pixel in components.

   * @param obj Array of TransferType or null.

   *

   * @return pixel value encoded according to the color model.

   * @throws ArrayIndexOutOfBoundsException

   * @throws ClassCastException

   * @since 1.4

   */

  public Object getDataElements(float[] components, int offset, Object obj)

  {

    return

      getDataElements(getUnnormalizedComponents(components, offset, null, 0),

                      0, obj);

  }

  public boolean equals(Object obj)

  {

    if (!(obj instanceof ColorModel)) return false;

    ColorModel o = (ColorModel) obj;

    return

      (pixel_bits == o.pixel_bits) &&

      (transferType == o.transferType) &&

      (transparency == o.transparency) &&

      (hasAlpha == o.hasAlpha) &&

      (isAlphaPremultiplied == o.isAlphaPremultiplied) &&

      Arrays.equals(bits, o.bits) &&

      (cspace.equals(o.cspace));

  }

  public final ColorSpace getColorSpace()

  {

    return cspace;

  }

  public ColorModel coerceData(WritableRaster raster,

                               boolean isAlphaPremultiplied)

  {

    // This method should always be overridden, but is not abstract.

    throw new UnsupportedOperationException();

  }

  void coerceDataWorker(WritableRaster raster,

                        boolean isAlphaPremultiplied)

  {

    int w = raster.getWidth();

    int h = raster.getHeight();

    int x = raster.getMinX();

    int y = raster.getMinY();

    int size = w * h;

    int numColors = getNumColorComponents();

    int numComponents = getNumComponents();

    int alphaScale = (1 << getComponentSize(numColors)) - 1;

    double[] pixels = raster.getPixels(x, y, w, h, (double[]) null);

    for (int i = 0; i < size; i++)

      {

        double alpha = pixels[i * numComponents + numColors] / alphaScale;

        for (int c = 0; c < numColors; c++)

          {

            int offset = i * numComponents + c;

            if (isAlphaPremultiplied)

              pixels[offset] = Math.round(pixels[offset] * alpha);

            else

              pixels[offset] = Math.round(pixels[offset] / alpha);

          }

      }

    raster.setPixels(0, 0, w, h, pixels);

  }

  /**

   * Checks if the given raster has a compatible data-layout (SampleModel).

   * @param raster The Raster to test.

   * @return true if raster is compatible.

   */

  public boolean isCompatibleRaster(Raster raster)

  {

    SampleModel sampleModel = raster.getSampleModel();

    return isCompatibleSampleModel(sampleModel);

  }

  // Typically overridden

  public WritableRaster createCompatibleWritableRaster(int w, int h)

  {

    return new WritableRaster(createCompatibleSampleModel(w, h),

                              new Point(0, 0));

  }

  // Typically overridden

  public SampleModel createCompatibleSampleModel(int w, int h)

  {

    throw new UnsupportedOperationException();

  }

  // Typically overridden

  public boolean isCompatibleSampleModel(SampleModel sm)

  {

    return sm.getTransferType() == transferType;

  }

  public final int getTransferType ()

  {

    return transferType;

  }

  /**

   * Subclasses must override this method if it is possible for the

   * color model to have an alpha channel.

   *

   * @return null, as per JDK 1.3 doc. Subclasses will only return

   * null if no alpha raster exists.

   */

  public WritableRaster getAlphaRaster(WritableRaster raster)

  {

    return null;

    /* It is a mystery to me why we couldn't use the following code...

       if (!hasAlpha()) return null;

       SampleModel sm = raster.getSampleModel();

       int[] alphaBand = { sm.getNumBands() - 1 };

       SampleModel alphaModel = sm.createSubsetSampleModel(alphaBand);

       DataBuffer buffer = raster.getDataBuffer();

       Point origin = new Point(0, 0);

       return Raster.createWritableRaster(alphaModel, buffer, origin);

       ...here, and avoided overriding the method in subclasses,

       but the Sun docs state that this method always will return

       null, and that overriding is required. Oh, well.

    */

  }

  String stringParam()

  {

    return "pixel_bits=" + pixel_bits +

      ", cspace=" + cspace +

      ", transferType=" + transferType +

      ", transparency=" + transparency +

      ", hasAlpha=" + hasAlpha +

      ", isAlphaPremultiplied=" + isAlphaPremultiplied;

  }

  public String toString()

  {

    return getClass().getName() + "[" + stringParam() + "]";

  }

  /**

   * A color model optimized for standard sRGB.

   */

  private static class SRGBColorModel

    extends DirectColorModel

  {

    SRGBColorModel()