lookupop.java

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/*
 * @(#)LookupOp.java	1.48 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */


package java.awt.image;

import java.awt.color.ColorSpace;
import java.awt.geom.Rectangle2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.geom.Point2D;
import sun.awt.image.ImagingLib;

/**
 * This class implements a lookup operation from the source
 * to the destination.  The LookupTable object may contain a single array
 * or multiple arrays, subject to the restrictions below.
 * <p>
 * For Rasters, the lookup operates on bands.  The number of
 * lookup arrays may be one, in which case the same array is
 * applied to all bands, or it must equal the number of Source
 * Raster bands.
 * <p>
 * For BufferedImages, the lookup operates on color and alpha components.
 * The number of lookup arrays may be one, in which case the
 * same array is applied to all color (but not alpha) components.
 * Otherwise, the number of lookup arrays may
 * equal the number of Source color components, in which case no
 * lookup of the alpha component (if present) is performed.
 * If neither of these cases apply, the number of lookup arrays
 * must equal the number of Source color components plus alpha components,
 * in which case lookup is performed for all color and alpha components.
 * This allows non-uniform rescaling of multi-band BufferedImages.
 * <p>
 * BufferedImage sources with premultiplied alpha data are treated in the same
 * manner as non-premultiplied images for purposes of the lookup.  That is,
 * the lookup is done per band on the raw data of the BufferedImage source
 * without regard to whether the data is premultiplied.  If a color conversion
 * is required to the destination ColorModel, the premultiplied state of
 * both source and destination will be taken into account for this step.
 * <p>
 * Images with an IndexColorModel cannot be used.
 * <p>
 * If a RenderingHints object is specified in the constructor, the
 * color rendering hint and the dithering hint may be used when color
 * conversion is required.
 * <p>
 * This class allows the Source to be the same as the Destination.
 * 
 * @version 10 Feb 1997
 * @see LookupTable
 * @see java.awt.RenderingHints#KEY_COLOR_RENDERING
 * @see java.awt.RenderingHints#KEY_DITHERING
 */

public class LookupOp implements BufferedImageOp, RasterOp {
    private LookupTable ltable;
    private int numComponents;
    RenderingHints hints;
    
    /**
     * Constructs a <code>LookupOp</code> object given the lookup 
     * table and a <code>RenderingHints</code> object, which might 
     * be <code>null</code>.
     * @param lookup the specified <code>LookupTable</code>
     * @param hints the specified <code>RenderingHints</code>,
     *        or <code>null</code>
     */
    public LookupOp(LookupTable lookup, RenderingHints hints) {
        this.ltable = lookup;
        this.hints  = hints;
        numComponents = ltable.getNumComponents();
    }

    /**
     * Returns the <code>LookupTable</code>.
     * @return the <code>LookupTable</code> of this
     *         <code>LookupOp</code>.
     */
    public final LookupTable getTable() {
        return ltable;
    }

    /**
     * Performs a lookup operation on a <code>BufferedImage</code>.  
     * If the color model in the source image is not the same as that
     * in the destination image, the pixels will be converted
     * in the destination.  If the destination image is <code>null</code>,
     * a <code>BufferedImage</code> will be created with an appropriate 
     * <code>ColorModel</code>.  An <code>IllegalArgumentException</code>
     * might be thrown if the number of arrays in the 
     * <code>LookupTable</code> does not meet the restrictions
     * stated in the class comment above, or if the source image
     * has an <code>IndexColorModel</code>.
     * @param src the <code>BufferedImage</code> to be filtered
     * @param dst the <code>BufferedImage</code> in which to 
     *            store the results of the filter operation
     * @return the filtered <code>BufferedImage</code>.
     * @throws IllegalArgumentException if the number of arrays in the
     *         <code>LookupTable</code> does not meet the restrictions
     *         described in the class comments, or if the source image
     *         has an <code>IndexColorModel</code>.
     */
    public final BufferedImage filter(BufferedImage src, BufferedImage dst) {
        ColorModel srcCM = src.getColorModel();
        int numBands = srcCM.getNumColorComponents();
        ColorModel dstCM;
        if (srcCM instanceof IndexColorModel) {
            throw new
                IllegalArgumentException("LookupOp cannot be "+
                                         "performed on an indexed image");
        }
        int numComponents = ltable.getNumComponents();
        if (numComponents != 1 &&
            numComponents != srcCM.getNumComponents() &&
            numComponents != srcCM.getNumColorComponents())
        {
            throw new IllegalArgumentException("Number of arrays in the "+
                                               " lookup table ("+
                                               numComponents+
                                               " is not compatible with the "+
                                               " src image: "+src);
        }

        
        boolean needToConvert = false;
        
        int width = src.getWidth();
        int height = src.getHeight();

        if (dst == null) {
            dst = createCompatibleDestImage(src, null);
            dstCM = srcCM;
        }
        else {
            if (width != dst.getWidth()) {
                throw new
                    IllegalArgumentException("Src width ("+width+
                                             ") not equal to dst width ("+
                                             dst.getWidth()+")");
            }
            if (height != dst.getHeight()) {
                throw new
                    IllegalArgumentException("Src height ("+height+
                                             ") not equal to dst height ("+
                                             dst.getHeight()+")");
            }

            dstCM = dst.getColorModel();
            if (srcCM.getColorSpace().getType() !=
                dstCM.getColorSpace().getType())
            {
                needToConvert = true;
                dst = createCompatibleDestImage(src, null);
            }

        }
        
        BufferedImage origDst = dst;

        if (ImagingLib.filter(this, src, dst) == null) {
            // Do it the slow way
            WritableRaster srcRaster = src.getRaster();
            WritableRaster dstRaster = dst.getRaster();

            if (srcCM.hasAlpha()) {
                if (numBands-1 == numComponents || numComponents == 1) {
                    int minx = srcRaster.getMinX();
                    int miny = srcRaster.getMinY();
                    int[] bands = new int[numBands-1];
                    for (int i=0; i < numBands-1; i++) {
                        bands[i] = i;
                    }
                    srcRaster =
                        srcRaster.createWritableChild(minx, miny,
                                                      srcRaster.getWidth(),
                                                      srcRaster.getHeight(),
                                                      minx, miny,
                                                      bands);
                }
            }
            if (dstCM.hasAlpha()) {
                int dstNumBands = dstRaster.getNumBands();
                if (dstNumBands-1 == numComponents || numComponents == 1) {
                    int minx = dstRaster.getMinX();
                    int miny = dstRaster.getMinY();
                    int[] bands = new int[numBands-1];
                    for (int i=0; i < numBands-1; i++) {
                        bands[i] = i;
                    }
                    dstRaster =
                        dstRaster.createWritableChild(minx, miny,
                                                      dstRaster.getWidth(),
                                                      dstRaster.getHeight(),
                                                      minx, miny,
                                                      bands);
                }
            }

            filter(srcRaster, dstRaster);
        }
        
        if (needToConvert) {
            // ColorModels are not the same
            ColorConvertOp ccop = new ColorConvertOp(hints);
            ccop.filter(dst, origDst);
        }

        return origDst;
    }

    /**
     * Performs a lookup operation on a <code>Raster</code>.  
     * If the destination <code>Raster</code> is <code>null</code>, 
     * a new <code>Raster</code> will be created.
     * The <code>IllegalArgumentException</code> might be thrown 
     * if the source <code>Raster</code> and the destination 
     * <code>Raster</code> do not have the same
     * number of bands or if the number of arrays in the 
     * <code>LookupTable</code> does not meet the
     * restrictions stated in the class comment above.
     * @param src the source <code>Raster</code> to filter
     * @param dst the destination <code>WritableRaster</code> for the
     *            filtered <code>src</code>
     * @return the filtered <code>WritableRaster</code>.
     * @throws IllegalArgumentException if the source and destinations 
     *         rasters do not have the same number of bands, or the
     *         number of arrays in the <code>LookupTable</code> does 
     *         not meet the restrictions described in the class comments.
     *         
     */
    public final WritableRaster filter (Raster src, WritableRaster dst) {
        int numBands  = src.getNumBands();
        int dstLength = dst.getNumBands();
        int height    = src.getHeight();
        int width     = src.getWidth();
        int srcPix[]  = new int[numBands];
        
        // Create a new destination Raster, if needed

        if (dst == null) {
            dst = createCompatibleDestRaster(src);
        }
        else if (height != dst.getHeight() || width != dst.getWidth()) {
            throw new
                IllegalArgumentException ("Width or height of Rasters do not "+
                                          "match");
        }
        dstLength = dst.getNumBands();
        
        if (numBands != dstLength) {
            throw new
                IllegalArgumentException ("Number of channels in the src ("
                                          + numBands +
                                          ") does not match number of channels"
                                          + " in the destination ("
                                          + dstLength + ")");
        }
        int numComponents = ltable.getNumComponents();
        if (numComponents != 1 && numComponents != src.getNumBands()) {
            throw new IllegalArgumentException("Number of arrays in the "+
                                               " lookup table ("+
                                               numComponents+
                                               " is not compatible with the "+
                                               " src Raster: "+src);
        }

        
        if (ImagingLib.filter(this, src, dst) != null) {
            return dst;
        }

        // Optimize for cases we know about