gcc/libjava/java/awt/image/RescaleOp.java

/* Copyright (C) 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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package java.awt.image;

import java.awt.RenderingHints;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.Arrays;

/**
 * @author Jerry Quinn (jlquinn@optonline.net)
 */
public class RescaleOp implements BufferedImageOp, RasterOp
{
  private float[] scale;
  private float[] offsets;
  private RenderingHints hints = null;
  
  public RescaleOp(float[] scaleFactors,
		   float[] offsets,
		   RenderingHints hints)
  {
    this.scale = scaleFactors;
    this.offsets = offsets;
    this.hints = hints;
  }
  
  public RescaleOp(float scaleFactor,
		   float offset,
		   RenderingHints hints)
  {
    scale = new float[]{ scaleFactor };
    offsets = new float[]{offset};
    this.hints = hints;
  }

  public final float[] getScaleFactors(float[] scaleFactors)
  {
    if (scaleFactors == null)
      scaleFactors = new float[scale.length];
    System.arraycopy(scale, 0, scaleFactors, 0, scale.length);
    return scaleFactors;
  }

  public final float[] getOffsets(float[] offsets)
  {
    if (offsets == null)
      offsets = new float[this.offsets.length];
    System.arraycopy(this.offsets, 0, offsets, 0, this.offsets.length);
    return offsets;
  }

  public final int getNumFactors()
  {
    return scale.length;
  }

  /* (non-Javadoc)
   * @see java.awt.image.BufferedImageOp#getRenderingHints()
   */
  public RenderingHints getRenderingHints()
  {
    return hints;
  }

  /* (non-Javadoc)
   * @see java.awt.image.BufferedImageOp#filter(java.awt.image.BufferedImage, java.awt.image.BufferedImage)
   */
  public final BufferedImage filter(BufferedImage src, BufferedImage dst)
  {
    // TODO Make sure premultiplied alpha is handled correctly.
    // TODO See that color conversion is handled.
    // TODO figure out how to use rendering hints.
    if (scale.length != offsets.length)
      throw new IllegalArgumentException();

    ColorModel scm = src.getColorModel();
    if (dst == null) dst = createCompatibleDestImage(src, null);

    WritableRaster wsrc = src.getRaster();
    WritableRaster wdst = dst.getRaster();
    
    // Share constant across colors except alpha
    if (scale.length == 1 || scale.length == scm.getNumColorComponents())
      {
	// Construct a raster that doesn't include an alpha band.
	int[] subbands = new int[scm.getNumColorComponents()];
	for (int i=0; i < subbands.length; i++) subbands[i] = i;
	wsrc = 
	  wsrc.createWritableChild(wsrc.minX, wsrc.minY, wsrc.width, wsrc.height,
				   wsrc.minX, wsrc.minY, subbands);
      }
    // else all color bands

    filter(wsrc, wdst);
    return dst;
  }

  /* (non-Javadoc)
   * @see java.awt.image.RasterOp#filter(java.awt.image.Raster, java.awt.image.WritableRaster)
   */
  public final WritableRaster filter(Raster src, WritableRaster dest)
  {
    if (dest == null) dest = src.createCompatibleWritableRaster();

    // Required sanity checks
    if (src.numBands != dest.numBands || scale.length != offsets.length)
      throw new IllegalArgumentException();
    if (scale.length != 1 && scale.length != src.numBands)
      throw new IllegalArgumentException();

    // Create scaling arrays if needed
    float[] lscale = scale;
    float[] loff = offsets;
    if (scale.length == 1)
      {
	lscale = new float[src.numBands];
	Arrays.fill(lscale, scale[0]);
	loff = new float[src.numBands];
	Arrays.fill(loff, offsets[0]);
      }

    // TODO The efficiency here can be improved for various data storage
    // patterns, aka SampleModels.
    float[] pixel = new float[src.numBands];
    for (int y = src.minY; y < src.height + src.minY; y++)
      for (int x = src.minX; x < src.width + src.minX; x++)
	{
	  src.getPixel(x, y, pixel);
	  for (int b = 0; b < src.numBands; b++)
	    pixel[b] = pixel[b] * lscale[b] + loff[b];
	  dest.setPixel(x, y, pixel);
	}
    return dest;
  }

  /* (non-Javadoc)
   * @see java.awt.image.BufferedImageOp#createCompatibleDestImage(java.awt.image.BufferedImage, java.awt.image.ColorModel)
   */
  public BufferedImage createCompatibleDestImage(BufferedImage src,
						 ColorModel dstCM)
  {
    if (dstCM == null) dstCM = src.getColorModel();
    WritableRaster wr = src.getRaster().createCompatibleWritableRaster();
    BufferedImage image
      = new BufferedImage(dstCM, wr, src.isPremultiplied, null);
    return image;
  }

  /* (non-Javadoc)
   * @see java.awt.image.RasterOp#createCompatibleDestRaster(java.awt.image.Raster)
   */
  public WritableRaster createCompatibleDestRaster(Raster src)
  {
    return src.createCompatibleWritableRaster();
  }
  
  /* (non-Javadoc)
   * @see java.awt.image.BufferedImageOp#getBounds2D(java.awt.image.BufferedImage)
   */
  public final Rectangle2D getBounds2D(BufferedImage src)
  {
    return src.getRaster().getBounds();
  }

  /* (non-Javadoc)
   * @see java.awt.image.RasterOp#getBounds2D(java.awt.image.Raster)
   */
  public final Rectangle2D getBounds2D(Raster src)
  {
    return src.getBounds();
  }

  /* (non-Javadoc)
   * @see java.awt.image.BufferedImageOp#getPoint2D(java.awt.geom.Point2D, java.awt.geom.Point2D)
   */
  public final Point2D getPoint2D(Point2D src, Point2D dst) {
    if (dst == null) dst = (Point2D) src.clone();
    else dst.setLocation(src);
    return dst;
  }

}