/* ImageLoaderDocuImage -- Image class implementation using JDK 1.4 ImageLoader

 Digital Image Library servlet components

 Copyright (C) 2002 - 2011 Robert Casties (robcast@mail.berlios.de)

 This program is free software; you can redistribute  it and/or modify it
 under  the terms of  the GNU General  Public License as published by the
 Free Software Foundation;  either version 2 of the  License, or (at your
 option) any later version.
 
 Please read license.txt for the full details. A copy of the GPL
 may be found at http://www.gnu.org/copyleft/lgpl.html

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package digilib.image;

import java.awt.Image;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.color.ColorSpace;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.AffineTransformOp;
import java.awt.image.BandCombineOp;
import java.awt.image.BufferedImage;
import java.awt.image.ByteLookupTable;
import java.awt.image.ColorConvertOp;
import java.awt.image.ColorModel;
import java.awt.image.ConvolveOp;
import java.awt.image.IndexColorModel;
import java.awt.image.Kernel;
import java.awt.image.LookupOp;
import java.awt.image.LookupTable;
import java.awt.image.RescaleOp;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.util.Arrays;
import java.util.Iterator;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.FileImageInputStream;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;

import digilib.io.FileOpException;
import digilib.io.FileOps;
import digilib.io.ImageInput;
import digilib.util.ImageSize;

/**
 * Implementation of DocuImage using the ImageLoader API of Java 1.4 and Java2D.
 */
public class ImageLoaderDocuImage extends ImageInfoDocuImage {

    /** DocuImage version */
    public static final String version = "ImageLoaderDocuImage 2.1.6a";

    /** image object */
    protected BufferedImage img;

    /** the reader object */
    protected ImageReader reader = null;

    /** try to reuse reader object */
    public boolean reuseReader = false;

    /** interpolation type */
    protected RenderingHints renderHint = null;

    /** convolution kernels for blur() */
    protected static Kernel[] convolutionKernels = { 
            null, new Kernel(1, 1, new float[] { 1f }),
            new Kernel(2, 2, new float[] { 0.25f, 0.25f, 
                                           0.25f, 0.25f }),
            new Kernel(3, 3, new float[] { 1f / 9f, 1f / 9f, 1f / 9f, 
                                           1f / 9f, 1f / 9f, 1f / 9f, 
                                           1f / 9f, 1f / 9f, 1f / 9f }) };

    /* lookup tables for inverting images (byte) */
    protected static LookupTable invertSingleByteTable;
    protected static LookupTable invertRgbaByteTable;
    protected static boolean needsInvertRgba = false;
    /* RescaleOp for contrast/brightness operation */
    protected static boolean needsRescaleRgba = false;
    /* lookup table for false-color */
    protected static LookupTable mapBgrByteTable;
    protected static boolean needsMapBgr = false;
    /* set destination type to sRGB if available, even for non-RGB images */
    protected static boolean alwaysSetDestSrgb = false;

    static {
        /*
         * create static lookup tables
         */
        byte[] invertByte = new byte[256];
        byte[] orderedByte = new byte[256];
        byte[] nullByte = new byte[256];
        byte[] mapR = new byte[256];
        byte[] mapG = new byte[256];
        byte[] mapB = new byte[256];
        for (int i = 0; i < 256; ++i) {
            // counting down
            invertByte[i] = (byte) (255 - i);
            // counting up
            orderedByte[i] = (byte) i;
            // constant 0
            nullByte[i] = 0;
            // three overlapping slopes
            if (i < 64) {
                mapR[i] = 0;
                mapG[i] = (byte) (4 * i);
                mapB[i] = (byte) 255;
            } else if (i >= 64 && i < 192) {
                mapR[i] = (byte) (2 * (i - 64));
                mapG[i] = (byte) 255;
                mapB[i] = (byte) (255 - 2 * (i - 64));
            } else {
                mapR[i] = (byte) 255;
                mapG[i] = (byte) (255 - (4 * (i - 192)));
                mapB[i] = 0;
            }
        }
        // should(!) work for all color models
        invertSingleByteTable = new ByteLookupTable(0, invertByte);
        invertRgbaByteTable = invertSingleByteTable;
        // but doesn't work with alpha channel on all platforms
        String ver = System.getProperty("java.version");
        String os = System.getProperty("os.name");
        String osver = System.getProperty("os.version");
        logger.debug("os="+os+" ver="+osver+" java_version="+ver);
        if ((os.startsWith("Linux"))
            || (os.startsWith("Mac OS X") && osver.startsWith("10.7"))) {
            // GRAB(WTF?) works for Linux JDK1.6 with transparency
            needsInvertRgba = true;
            invertRgbaByteTable = new ByteLookupTable(0, new byte[][] { invertByte, invertByte, orderedByte, invertByte });
            needsRescaleRgba = true;
            needsMapBgr = true;
        } else if ((os.startsWith("Mac OS X") && (osver.startsWith("10.5") || osver.startsWith("10.6"))) 
            || (os.startsWith("Windows"))) {
            needsRescaleRgba = true;
        }
        // this hopefully works for all
        mapBgrByteTable = new ByteLookupTable(0, new byte[][] { mapR, mapG, mapB });
        logger.debug("ImageIO Hacks: needsRescaleRgba="+needsRescaleRgba+" needsInvertRgba="+needsInvertRgba+
                " needsMapBgr="+needsMapBgr);
    }

    /** the size of the current image */
    protected ImageSize imageSize;

    /**
     * @return the version
     */
    public String getVersion() {
        return version;
    }

    /* loadSubimage is supported. */
    public boolean isSubimageSupported() {
        return true;
    }

    public void setQuality(int qual) {
        quality = qual;
        renderHint = new RenderingHints(null);
        // hint.put(RenderingHints.KEY_ANTIALIASING,
        // RenderingHints.VALUE_ANTIALIAS_OFF);
        // setup interpolation quality
        if (qual > 0) {
            logger.debug("quality q1");
            renderHint.put(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        } else {
            logger.debug("quality q0");
            renderHint.put(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR);
        }
    }

    /* returns the size of the current image */
    public ImageSize getSize() {
        if (imageSize == null) {
            int h = 0;
            int w = 0;
            try {
                if (img == null) {
                    reader = getReader(input);
                    // get size from ImageReader
                    h = reader.getHeight(0);
                    w = reader.getWidth(0);
                } else {
                    // get size from image
                    h = img.getHeight();
                    w = img.getWidth();
                }
                imageSize = new ImageSize(w, h);
            } catch (IOException e) {
                logger.debug("error in getSize:", e);
            }
        }
        return imageSize;
    }

    /* returns a list of supported image formats */
    public Iterator<String> getSupportedFormats() {
        String[] formats = ImageIO.getReaderFormatNames();
        return Arrays.asList(formats).iterator();
    }

    /* Check image size and type and store in ImageInput */
    public ImageInput identify(ImageInput input) throws IOException {
        ImageInput ii = null;
        if (!reuseReader) {
            // try parent method first
            ii = super.identify(input);
            if (ii != null) {
                return ii;
            }
        }
        logger.debug("identifying (ImageIO) " + input);
        try {
            /*
             * try ImageReader
             */
            reader = getReader(input);
            // set size
            ImageSize d = new ImageSize(reader.getWidth(0), reader.getHeight(0));
            input.setSize(d);
            // set mime type
            if (input.getMimetype() == null) {
                if (input.hasFile()) {
                    String t = FileOps.mimeForFile(input.getFile());
                    input.setMimetype(t);
                } else {
                    // FIXME: is format name a mime type???
                    String t = reader.getFormatName();
                    input.setMimetype(t);
                }
            }
            return input;
        } catch (FileOpException e) {
            // maybe just our class doesn't know what to do
            logger.error("ImageLoaderDocuimage unable to identify:", e);
            return null;
        } finally {
            if (!reuseReader && reader != null) {
                reader.dispose();
            }
        }
    }

    /* load image file */
    public void loadImage(ImageInput ii) throws FileOpException {
        logger.debug("loadImage: " + ii);
        this.input = ii;
        try {
            if (ii.hasImageInputStream()) {
                img = ImageIO.read(ii.getImageInputStream());
            } else if (ii.hasFile()) {
                img = ImageIO.read(ii.getFile());
            }
        } catch (IOException e) {
            throw new FileOpException("Error reading image!", e);
        }
        if (img == null) {
            throw new FileOpException("Unable to read image!");
        }
    }

    /**
     * Get an ImageReader for the image file.
     * 
     * @return
     */
    public ImageReader getReader(ImageInput input) throws IOException {
        logger.debug("get ImageReader for " + input);
        if (reuseReader && reader != null) {
            logger.debug("reuseing ImageReader");
            return reader;
        }
        ImageInputStream istream = null;
        if (input.hasImageInputStream()) {
            // ImageInputStream input
            istream = input.getImageInputStream();
        } else if (input.hasFile()) {
            // file only input
            RandomAccessFile rf = new RandomAccessFile(input.getFile(), "r");
            istream = new FileImageInputStream(rf);
        } else {
            throw new FileOpException("Unable to get data from ImageInput");
        }
        Iterator<ImageReader> readers;
        String mt = null;
        if (input.hasMimetype()) {
            // check hasMimetype first or we might get into a loop
            mt = input.getMimetype();
        } else {
            // try file extension
            mt = FileOps.mimeForFile(input.getFile());
        }
        if (mt == null) {
            logger.debug("No mime-type. Trying automagic.");
            readers = ImageIO.getImageReaders(istream);
        } else {
            logger.debug("File type:" + mt);
            readers = ImageIO.getImageReadersByMIMEType(mt);
        }
        if (!readers.hasNext()) {
            throw new FileOpException("Can't find Reader to load File!");
        }
        ImageReader reader = readers.next();
        logger.debug("ImageIO: this reader: " + reader.getClass());
        /*
         * while (readers.hasNext()) { logger.debug("ImageIO: next reader: " +
         * readers.next().getClass()); }
         */
        reader.setInput(istream);
        return reader;
    }

    /* Load an image file into the Object. */
    public void loadSubimage(ImageInput ii, Rectangle region, int prescale) throws FileOpException {
        logger.debug("loadSubimage");
        this.input = ii;
        // ImageReader reader = null;
        try {
            reader = getReader(ii);
            // set up reader parameters
            ImageReadParam readParam = reader.getDefaultReadParam();
            readParam.setSourceRegion(region);
            if (prescale > 1) {
                readParam.setSourceSubsampling(prescale, prescale, 0, 0);
            }
            // try to set target color space to sRGB
            for (Iterator<ImageTypeSpecifier> i = reader.getImageTypes(0); i.hasNext();) {
                ImageTypeSpecifier type = (ImageTypeSpecifier) i.next();
                ColorModel cm = type.getColorModel();
                ColorSpace cs = cm.getColorSpace();
                logger.debug("loadSubimage: possible color model:"+cm+" color space:"+cs);
                if (cs.getNumComponents() < 3 && ! ImageLoaderDocuImage.alwaysSetDestSrgb) {
                    // if the first type is not RGB do nothing
                    logger.debug("loadSubimage: image is not RGB " + type);
                    break;
                }
                if (cs.isCS_sRGB()) {
                    logger.debug("loadSubimage: substituted sRGB destination type " + type);
                    readParam.setDestinationType(type);
                    break;
                }
            }
            // read image
            logger.debug("loadSubimage: loading..");
            img = reader.read(0, readParam);
            logger.debug("loadSubimage: loaded");
            // invalidate image size if it was set
            imageSize = null;
            // downconvert highcolor images
            if (img.getColorModel().getComponentSize(0) > 8) {
                logger.debug("loadSubimage: converting to 8bit");
                int type = BufferedImage.TYPE_INT_RGB;
                if (img.getColorModel().hasAlpha()) {
                    type = BufferedImage.TYPE_INT_ARGB;
                }
                BufferedImage lcImg = new BufferedImage(img.getWidth(), img.getHeight(), type);
                lcImg.createGraphics().drawImage(img, null, 0, 0);
                img = lcImg;
            }
        } catch (IOException e) {
            throw new FileOpException("Unable to load File!", e);
        } finally {
            if (!reuseReader && reader != null) {
                reader.dispose();
            }
        }
    }

    /* write image of type mt to Stream */
    public void writeImage(String mt, OutputStream ostream) throws ImageOpException, FileOpException {
        logger.debug("writeImage");
        // setup output
        ImageWriter writer = null;
        ImageOutputStream imgout = null;
        try {
            imgout = ImageIO.createImageOutputStream(ostream);
            if (mt == "image/jpeg") {
                /*
                 * JPEG doesn't do transparency so we have to convert any RGBA
                 * image to RGB or we the client will think its CMYK :-( *Java2D
                 * BUG*
                 */
                if (img.getColorModel().hasAlpha()) {
                    logger.debug("BARF: JPEG with transparency!!");
                    BufferedImage rgbImg = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_RGB);
                    rgbImg.createGraphics().drawImage(img, null, 0, 0);
                    img = rgbImg;
                }
                writer = ImageIO.getImageWritersByFormatName("jpeg").next();
                if (writer == null) {
                    throw new ImageOpException("Unable to get JPEG writer");
                }
                ImageWriteParam param = writer.getDefaultWriteParam();
                if (quality > 1) {
                    // change JPEG compression quality
                    param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
                    param.setCompressionQuality(0.9f);
                }
                writer.setOutput(imgout);
                // render output
                logger.debug("writing JPEG");
                writer.write(null, new IIOImage(img, null, null), param);
            } else if (mt == "image/png") {
                // render output
                writer = ImageIO.getImageWritersByFormatName("png").next();
                if (writer == null) {
                    throw new ImageOpException("Unable to get PNG writer");
                }
                writer.setOutput(imgout);
                logger.debug("writing PNG");
                writer.write(img);
            } else {
                // unknown mime type
                throw new ImageOpException("Unknown mime type: " + mt);
            }

        } catch (IOException e) {
            logger.error("Error writing image:", e);
            throw new FileOpException("Error writing image!", e);
        }
        // TODO: should we: finally { writer.dispose(); }
    }

    public void scale(double scaleX, double scaleY) throws ImageOpException {
        logger.debug("scale: " + scaleX);
        /* for downscaling in high quality the image is blurred first */
        if ((scaleX <= 0.5) && (quality > 1)) {
            int bl = (int) Math.floor(1 / scaleX);
            blur(bl);
        }
        /* then scaled */
        AffineTransformOp scaleOp = new AffineTransformOp(AffineTransform.getScaleInstance(scaleX, scaleY), renderHint);
        img = scaleOp.filter(img, null);
        logger.debug("scaled to " + img.getWidth() + "x" + img.getHeight() + " img=" + img);
        // invalidate image size
        imageSize = null;
    }

    public void blur(int radius) throws ImageOpException {
        logger.debug("blur: " + radius);
        // minimum radius is 2
        int klen = Math.max(radius, 2);
        Kernel blur = null;
        if (klen < convolutionKernels.length) {
            // use precalculated Kernel
            blur = convolutionKernels[klen];
        } else {
            // calculate our own kernel
            int ksize = klen * klen;
            // kernel is constant 1/k
            float f = 1f / ksize;
            float[] kern = new float[ksize];
            for (int i = 0; i < ksize; ++i) {
                kern[i] = f;
            }
            blur = new Kernel(klen, klen, kern);
        }
        // blur with convolve operation
        ConvolveOp blurOp = new ConvolveOp(blur, ConvolveOp.EDGE_NO_OP, renderHint);
        BufferedImage dest = null;
        // blur needs explicit destination image type for 3BYTE_BGR *Java2D BUG*
        if (img.getType() == BufferedImage.TYPE_3BYTE_BGR) {
            logger.debug("blur: fixing destination image type");
            dest = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
        }
        img = blurOp.filter(img, dest);
        logger.debug("blurred: " + img);
    }

    public void crop(int x_off, int y_off, int width, int height) throws ImageOpException {
        // setup Crop
        img = img.getSubimage(x_off, y_off, width, height);
        logger.debug("CROP:" + img.getWidth() + "x" + img.getHeight());
        // invalidate image size
        imageSize = null;
    }

    public void rotate(double angle) throws ImageOpException {
        logger.debug("rotate: " + angle);
        // setup rotation
        double rangle = Math.toRadians(angle);
        // center of rotation is center of image
        double w = img.getWidth();
        double h = img.getHeight();
        double x = (w / 2);
        double y = (h / 2);
        AffineTransform trafo = AffineTransform.getRotateInstance(rangle, x, y);
        AffineTransformOp rotOp = new AffineTransformOp(trafo, renderHint);
        // rotate bounds to see how much of the image would be off screen
        Rectangle2D rotbounds = rotOp.getBounds2D(img);
        double xoff = rotbounds.getX();
        double yoff = rotbounds.getY();
        if (Math.abs(xoff) > epsilon || Math.abs(yoff) > epsilon) {
            // move image back on screen
            logger.debug("move rotation: xoff=" + xoff + " yoff=" + yoff);
            trafo.preConcatenate(AffineTransform.getTranslateInstance(-xoff, -yoff));
            rotOp = new AffineTransformOp(trafo, renderHint);
        }
        // transform image
        img = rotOp.filter(img, null);
        logger.debug("rotated: " + img);
        // invalidate image size
        imageSize = null;
    }

    public void mirror(double angle) throws ImageOpException {
        logger.debug("mirror: " + angle);
        // setup mirror
        double mx = 1;
        double my = 1;
        double tx = 0;
        double ty = 0;
        if (Math.abs(angle - 0) < epsilon) { // 0 degree
            mx = -1;
            tx = img.getWidth();
        } else if (Math.abs(angle - 90) < epsilon) { // 90 degree
            my = -1;
            ty = img.getHeight();
        } else if (Math.abs(angle - 180) < epsilon) { // 180 degree
            mx = -1;
            tx = img.getWidth();
        } else if (Math.abs(angle - 270) < epsilon) { // 270 degree
            my = -1;
            ty = img.getHeight();
        } else if (Math.abs(angle - 360) < epsilon) { // 360 degree
            mx = -1;
            tx = img.getWidth();
        } else {
            logger.error("invalid mirror angle " + angle);
            return;
        }
        AffineTransformOp mirOp = new AffineTransformOp(new AffineTransform(mx, 0, 0, my, tx, ty), renderHint);
        img = mirOp.filter(img, null);
        // invalidate image size
        imageSize = null;
    }

    public void enhance(float mult, float add) throws ImageOpException {
        RescaleOp op = null;
        logger.debug("enhance: img=" + img);
        if (needsRescaleRgba) {
            /*
             * Only one constant should work regardless of the number of bands
             * according to the JDK spec. Doesn't work on JDK 1.4 for OSX and
             * Linux (at least).
             * 
             * The number of constants must match the number of bands in the
             * image.
             */
            int ncol = img.getColorModel().getNumComponents();
            float[] dm = new float[ncol];
            float[] da = new float[ncol];
            for (int i = 0; i < ncol; i++) {
                dm[i] = mult;
                da[i] = add;
            }
            if (img.getColorModel().hasAlpha()) {
                // alpha channel should not be scaled
                dm[ncol-1] = 1f;
                da[ncol-1] = 0f;
            }
            op = new RescaleOp(dm, da, renderHint);
        } else {
            op = new RescaleOp(mult, add, renderHint);
        }
        op.filter(img, img);
    }

    public void enhanceRGB(float[] rgbm, float[] rgba) throws ImageOpException {
        logger.debug("enhanceRGB: rgbm=" + rgbm + " rgba=" + rgba);
        /*
         * The number of constants must match the number of bands in the image.
         * We do only 3 (RGB) bands.
         */
        int ncol = img.getColorModel().getNumColorComponents();
        if ((ncol != 3) || (rgbm.length != 3) || (rgba.length != 3)) {
            logger.error("enhanceRGB: unknown number of color bands or coefficients (" + ncol + ")");
            return;
        }
        if (img.getColorModel().hasAlpha()) {
            // add constant for alpha
            rgbm = new float[] { rgbm[0], rgbm[1], rgbm[2], 1 };
            rgba = new float[] { rgba[0], rgba[1], rgba[2], 0 };
        }
        RescaleOp scaleOp = new RescaleOp(rgbm, rgba, renderHint);
        scaleOp.filter(img, img);
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * digilib.image.DocuImageImpl#colorOp(digilib.image.DocuImage.ColorOps)
     */
    public void colorOp(ColorOp colop) throws ImageOpException {
        if (colop == ColorOp.GRAYSCALE) {
            /*
             * convert image to grayscale
             */
            logger.debug("Color op: grayscaling");
            ColorModel cm = img.getColorModel();
            if (cm.getNumColorComponents() < 3) {
                // grayscale already
                logger.debug("Color op: not grayscaling");
                return;
            }
            ColorConvertOp op = new ColorConvertOp(ColorSpace.getInstance(ColorSpace.CS_GRAY), renderHint);
            // let filter create new image
            img = op.filter(img, null);
        } else if (colop == ColorOp.NTSC_GRAY) {
            /*
             * convert image to grayscale NTSC-style: luminance = 0.2989*red +
             * 0.5870*green + 0.1140*blue
             */
            logger.debug("Color op: NTSC gray");
            logger.debug("img=" + img);
            ColorModel cm = img.getColorModel();
            if (cm.getNumColorComponents() < 3 || cm instanceof IndexColorModel) {
                // grayscale already or not possible
                logger.debug("Color op: unable to NTSC gray");
                return;
            }
            float[][] combineFn = new float[1][4];
            combineFn[0] = new float[] { 0.299f, 0.587f, 0.114f, 0f };
            BandCombineOp op = new BandCombineOp(combineFn, renderHint);
            // BandCombineOp only works on Rasters so we create a
            // new image and use its Raster
            BufferedImage dest = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
            op.filter(img.getRaster(), dest.getRaster());
            img = dest;
        } else if (colop == ColorOp.INVERT) {
            /*
             * invert colors i.e. invert every channel
             */
            logger.debug("Color op: inverting");
            LookupTable invtbl = null;
            ColorModel cm = img.getColorModel();
            if (cm instanceof IndexColorModel) {
                // invert not possible
                // TODO: should we convert?
                logger.debug("Color op: unable to invert");
                return;
            }
            if (needsInvertRgba && cm.hasAlpha()) {
                // fix for some cases
                invtbl = invertRgbaByteTable;
            } else {
                invtbl = invertSingleByteTable;
            }
            LookupOp op = new LookupOp(invtbl, renderHint);
            logger.debug("colop: image=" + img);
            op.filter(img, img);
        } else if (colop == ColorOp.MAP_GRAY_BGR) {
            /*
             * false color image from grayscale (0: blue, 128: green, 255: red)
             */
            logger.debug("Color op: map_gray_bgr");
            // convert to grayscale
            ColorConvertOp grayOp = new ColorConvertOp(ColorSpace.getInstance(ColorSpace.CS_GRAY), renderHint);
            // create new 3-channel image
            int destType = BufferedImage.TYPE_INT_RGB;
            if (needsMapBgr) {
                // special case for funny Java2D implementations
                if (img.getColorModel().hasAlpha()) {
                    destType = BufferedImage.TYPE_4BYTE_ABGR_PRE;
                } else {
                    destType = BufferedImage.TYPE_3BYTE_BGR;
                }
            }
            BufferedImage dest = new BufferedImage(img.getWidth(), img.getHeight(), destType);
            img = grayOp.filter(img, dest);
            logger.debug("map_gray: image=" + img);
            // convert to false color
            LookupOp mapOp = new LookupOp(mapBgrByteTable, renderHint);
            mapOp.filter(img, img);
            logger.debug("mapped image=" + img);
        }
    }

    public void dispose() {
        if (reader != null) {
            reader.dispose();
        }
        // is this necessary?
        img = null;
    }

    public Image getAwtImage() {
        return (Image) img;
    }

}