+/* $RCSfile$
+ * $Author: hansonr $
+ * $Date: 2007-06-02 12:14:13 -0500 (Sat, 02 Jun 2007) $
+ * $Revision: 7831 $
+ *
+ * Some portions of this file have been modified by Robert Hanson hansonr.at.stolaf.edu 2012-2017
+ * for use in SwingJS via transpilation into JavaScript using Java2Script.
+ *
+ * Copyright (C) 2000-2005 The Jmol Development Team
+ *
+ * Contact: jmol-developers@lists.sf.net
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+// Final encoding code from http://acme.com/resources/classes/Acme/JPM/Encoders/GifEncoder.java
+//
+// GifEncoder - write out an image as a GIF
+//
+//
+// Transparency handling and variable bit size courtesy of Jack Palevich.
+//
+// Copyright (C)1996,1998 by Jef Poskanzer <jef@mail.acme.com>. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+// 1. Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+// SUCH DAMAGE.
+//
+// Visit the ACME Labs Java page for up-to-date versions of this and other
+// fine Java utilities: http://www.acme.com/java/
+//
+/// Write out an image as a GIF.
+// <P>
+// <A HREF="/resources/classes/Acme/JPM/Encoders/GifEncoder.java">Fetch the software.</A><BR>
+// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>
+// <P>
+// @see ToGif
+
+package javajs.img;
+
+import javajs.util.CU;
+import javajs.util.Lst;
+import javajs.util.M3;
+import javajs.util.P3;
+
+import java.util.Hashtable;
+import java.util.Map;
+import java.io.IOException;
+
+/**
+ *
+ * GifEncoder extensively adapted for Jmol by Bob Hanson
+ *
+ * Color quantization roughly follows the GIMP method
+ * "dither Floyd-Steinberg (normal)" but with some twists. (For example, we
+ * exclude the background color.)
+ *
+ * Note that although GIMP code annotation refers to "median-cut", it is really
+ * using MEAN-cut. That is what I use here as well.
+ *
+ * -- commented code allows visualization of the color space using Jmol. Very
+ * enlightening!
+ *
+ * -- much simplified interface with ImageEncoder
+ *
+ * -- uses simple Hashtable with Integer() to catalog colors
+ *
+ * -- allows progressive production of animated GIF via Jmol CAPTURE command
+ *
+ * -- uses general purpose javajs.util.OutputChannel for byte-handling options
+ * such as posting to a server, writing to disk, and retrieving bytes.
+ *
+ * -- allows JavaScript port
+ *
+ * -- Bob Hanson, first try: 24 Sep 2013; final coding: 9 Nov 2014
+ *
+ *
+ * @author Bob Hanson hansonr@stolaf.edu
+ */
+
+public class GifEncoder extends ImageEncoder {
+
+ private Map<String, Object> params;
+ private P3[] palette;
+ private int backgroundColor;
+
+ private boolean interlaced;
+ private boolean addHeader = true;
+ private boolean addImage = true;
+ private boolean addTrailer = true;
+ private boolean isTransparent;
+ private boolean floydSteinberg = true;
+ private boolean capturing;
+ private boolean looping;
+
+ private int delayTime100ths = -1;
+ private int bitsPerPixel = 1;
+
+ private int byteCount;
+
+ /**
+ * we allow for animated GIF by being able to re-enter the code with different
+ * parameters held in params
+ *
+ *
+ */
+ @Override
+ protected void setParams(Map<String, Object> params) {
+ this.params = params;
+ Integer ic = (Integer) params.get("transparentColor");
+ if (ic == null) {
+ ic = (Integer) params.get("backgroundColor");
+ if (ic != null)
+ backgroundColor = ic.intValue();
+ } else {
+ backgroundColor = ic.intValue();
+ isTransparent = true;
+ }
+
+ interlaced = (Boolean.TRUE == params.get("interlaced"));
+ if (params.containsKey("captureRootExt") // file0000.gif
+ || !params.containsKey("captureMode")) // animated gif
+ return;
+ interlaced = false;
+ capturing = true;
+ try {
+ byteCount = ((Integer) params.get("captureByteCount")).intValue();
+ } catch (Exception e) {
+ // ignore
+ }
+ switch ("maec"
+ .indexOf(((String) params.get("captureMode")).substring(0, 1))) {
+ case 0: //"movie"
+ params.put("captureMode", "add");
+ addImage = false;
+ addTrailer = false;
+ break;
+ case 1: // add
+ addHeader = false;
+ addTrailer = false;
+ int fps = Math.abs(((Integer) params.get("captureFps")).intValue());
+ delayTime100ths = (fps == 0 ? 0 : 100 / fps);
+ looping = (Boolean.FALSE != params.get("captureLooping"));
+ break;
+ case 2: // end
+ addHeader = false;
+ addImage = false;
+ break;
+ case 3: // cancel
+ addHeader = false;
+ addImage = false;
+ out.cancel();
+ break;
+ }
+ }
+
+ @Override
+ protected void generate() throws IOException {
+ if (addHeader)
+ writeHeader();
+ addHeader = false; // only one header
+ if (addImage) {
+ createPalette();
+ writeGraphicControlExtension();
+ if (delayTime100ths >= 0 && looping)
+ writeNetscapeLoopExtension();
+ writeImage();
+ }
+ }
+
+ @Override
+ protected void close() {
+ if (addTrailer) {
+ writeTrailer();
+ } else {
+ doClose = false;
+ }
+ if (capturing)
+ params.put("captureByteCount", Integer.valueOf(byteCount));
+ }
+
+ ////////////// 256-color quantization //////////////
+
+ /**
+ * a color point in normalized L*a*b space with a flag indicating whether it
+ * is the background color
+ */
+ private class ColorItem extends P3 {
+ /**
+ *
+ */
+ protected boolean isBackground;
+
+ ColorItem(int rgb, boolean isBackground) {
+ this.isBackground = isBackground;
+ setT(toLABnorm(rgb));
+ }
+ }
+
+ /**
+ * A list of normalized L*a*b points with an index and a center and volume
+ *
+ */
+ private class ColorCell extends Lst<P3> {
+
+ /**
+ *
+ */
+ private static final long serialVersionUID = 1L;
+ protected int index;
+ protected P3 center;
+
+ private float volume;
+
+ ColorCell(int index) {
+ this.index = index;
+ }
+
+ /**
+ * @param doVisualize
+ * debugging only
+ * @return volume in normalized L*a*b space
+ */
+ public float getVolume(boolean doVisualize) {
+ if (volume != 0)
+ return volume;
+ if (size() < 2)
+ return -1;
+ //if (true)
+ //return lst.size();
+ //float d;
+ float maxx = -Integer.MAX_VALUE;
+ float minx = Integer.MAX_VALUE;
+ float maxy = -Integer.MAX_VALUE;
+ float miny = Integer.MAX_VALUE;
+ float maxz = -Integer.MAX_VALUE;
+ float minz = Integer.MAX_VALUE;
+ int n = size();
+ for (int i = n; --i >= 0;) {
+ P3 xyz = get(i);
+ if (xyz.x < minx)
+ minx = xyz.x;
+ if (xyz.y < miny)
+ miny = xyz.y;
+ if (xyz.z < minz)
+ minz = xyz.z;
+ if (xyz.x > maxx)
+ maxx = xyz.x;
+ if (xyz.y > maxy)
+ maxy = xyz.y;
+ if (xyz.z > maxz)
+ maxz = xyz.z;
+ }
+ float dx = (maxx - minx);
+ float dy = (maxy - miny);
+ float dz = (maxz - minz);
+ // Jmol visualization only
+ // if (doVisualize) {
+ // P3 ptRGB = toRGB(center);
+ // drawPt(index, -size(), ptRGB);
+ // //for (int i = n; --i >= 0;)
+ // //drawPt(index, i, toRGB(get(i)));
+ // P3 pt0 = toRGB(P3.new3(Math.max(minx, 0), Math.max(miny, 0),
+ // Math.max(minz, 0)));
+ // P3 pt1 = toRGB(P3.new3(Math.min(maxx, 100), Math.min(maxy, 100),
+ // Math.min(maxz, 100)));
+ // rgbToXyz(pt0, pt0);
+ // xyzToLab(pt0, pt0);
+ // rgbToXyz(pt1, pt1);
+ // xyzToLab(pt1, pt1);
+ // System.out.println("boundbox corners " + pt0 + " " + pt1);
+ // System.out.println("draw d" + index + " boundbox color " + ptRGB
+ // + " mesh nofill");
+ // }
+ return volume = dx * dx + dy * dy + dz * dz;
+ }
+
+ // // Jmol visualization only
+ // private void drawPt(int index, int i, P3 rgb) {
+ // boolean isMain = (i < 0);
+ // P3 lab = rgbToXyz(rgb, null);
+ // xyzToLab(lab, lab);
+ // System.out.println("draw d" + index + (isMain ? "_" : "_" + i) + " width "
+ // + (isMain ? 1.0 : 0.2) + " " + lab
+ // + " color " + rgb + (isMain ? " '" + -i + "'" : ""));
+ // }
+
+ /**
+ * Set the average normalized L*a*b value for this cell and return its RGB point
+ *
+ * @return RGB point
+ *
+ */
+ protected P3 setColor() {
+ int count = size();
+ center = new P3();
+ for (int i = count; --i >= 0;)
+ center.add(get(i));
+ center.scale(1f / count);
+ // Jmol visualization only
+ //volume = 0;
+ //getVolume(true);
+ return toRGB(center);
+ }
+
+ /**
+ * use median_cut algorithm to split the cell, creating a doubly linked
+ * list.
+ *
+ * Paul Heckbert, MIT thesis COLOR IMAGE QUANTIZATION FOR FRAME BUFFER
+ * DISPLAY https://www.cs.cmu.edu/~ph/ciq_thesis
+ *
+ * except, as in GIMP, we use center (not median) here.
+ *
+ * @param cells
+ * @return true if split
+ */
+ protected boolean splitCell(Lst<ColorCell> cells) {
+ int n = size();
+ if (n < 2)
+ return false;
+ int newIndex = cells.size();
+ ColorCell newCell = new ColorCell(newIndex);
+ cells.addLast(newCell);
+ float[][] ranges = new float[3][3];
+ for (int ic = 0; ic < 3; ic++) {
+ float low = Float.MAX_VALUE;
+ float high = -Float.MAX_VALUE;
+ for (int i = n; --i >= 0;) {
+ P3 lab = get(i);
+ float v = (ic == 0 ? lab.x : ic == 1 ? lab.y : lab.z);
+ if (low > v)
+ low = v;
+ if (high < v)
+ high = v;
+ }
+ ranges[0][ic] = low;
+ ranges[1][ic] = high;
+ ranges[2][ic] = high - low;
+ }
+ float[] r = ranges[2];
+ int mode = (r[0] >= r[1] ? (r[0] >= r[2] ? 0 : 2) : r[1] >= r[2] ? 1 : 2);
+ float val = ranges[0][mode] + ranges[2][mode] / 2;
+ volume = 0; // recalculate volume if needed
+ switch (mode) {
+ case 0:
+ for (int i = n; --i >= 0;)
+ if (get(i).x >= val)
+ newCell.addLast(removeItemAt(i));
+ break;
+ case 1:
+ for (int i = n; --i >= 0;)
+ if (get(i).y >= val)
+ newCell.addLast(removeItemAt(i));
+ break;
+ case 2:
+ for (int i = size(); --i >= 0;)
+ if (get(i).z >= val)
+ newCell.addLast(removeItemAt(i));
+ break;
+ }
+ return true;
+ }
+ }
+
+ /**
+ * Quantize all colors and create the final palette;
+ * replace pixels[] with an array of color indices.
+ *
+ */
+ private void createPalette() {
+
+ // catalog all pixel colors
+
+ Lst<ColorItem> tempColors = new Lst<ColorItem>();
+ Map<Integer, ColorItem> ciHash = new Hashtable<Integer, ColorItem>();
+ for (int i = 0, n = pixels.length; i < n; i++) {
+ int rgb = pixels[i];
+ Integer key = Integer.valueOf(rgb);
+ ColorItem item = ciHash.get(key);
+ if (item == null) {
+ item = new ColorItem(rgb, rgb == backgroundColor);
+ ciHash.put(key, item);
+ tempColors.addLast(item);
+ }
+ }
+ int nColors = tempColors.size();
+ System.out.println("GIF total image colors: " + nColors);
+ ciHash = null;
+
+ // create a set of <= 256 color cells
+
+ Lst<ColorCell> cells = quantizeColors(tempColors);
+ nColors = cells.size();
+ System.out.println("GIF final color count: " + nColors);
+
+ // generate the palette and map each cell's rgb color to itself
+
+ Map<Integer, ColorCell> colorMap = new Hashtable<Integer, ColorCell>();
+ bitsPerPixel = (nColors <= 2 ? 1 : nColors <= 4 ? 2 : nColors <= 16 ? 4 : 8);
+ palette = new P3[1 << bitsPerPixel];
+ for (int i = 0; i < nColors; i++) {
+ ColorCell c = cells.get(i);
+ colorMap.put(
+ Integer.valueOf(CU.colorPtToFFRGB(palette[i] = c.setColor())), c);
+ }
+
+ // index all pixels to a pallete color
+
+ pixels = indexPixels(cells, colorMap);
+ }
+
+ /**
+ * Quantize colors by generating a set of cells in normalized L*a*b space
+ * containing all colors. Start with just two cells -- fixed background color
+ * and all others. Keep splitting cells while there are fewer than 256 and
+ * some with multiple colors in them.
+ *
+ * It is possible that we will end up with fewer than 256 colors.
+ *
+ * @param tempColors
+ * @return final list of colors
+ */
+ private Lst<ColorCell> quantizeColors(Lst<ColorItem> tempColors) {
+ int n = tempColors.size();
+ Lst<ColorCell> cells = new Lst<ColorCell>();
+ ColorCell cc = new ColorCell(0);
+ cc.addLast(new ColorItem(backgroundColor, true));
+ cells.addLast(cc);
+ cc = new ColorCell(1);
+ if (n > 256)
+ cells.addLast(cc);
+ for (int i = 0; i < n; i++) {
+ ColorItem c = tempColors.get(i);
+ if (c.isBackground)
+ continue;
+ cc.addLast(c);
+ if (n <= 256) {
+ cells.addLast(cc);
+ cc = new ColorCell(cells.size());
+ }
+ }
+ tempColors.clear();
+ if (n > 256)
+ while ((n = cells.size()) < 256) {
+ float maxVol = 0;
+ ColorCell maxCell = null;
+ for (int i = n; --i >= 1;) {
+ ColorCell c = cells.get(i);
+ float v = c.getVolume(false);
+ if (v > maxVol) {
+ maxVol = v;
+ maxCell = c;
+ }
+ }
+ if (maxCell == null || !maxCell.splitCell(cells))
+ break;
+ }
+ return cells;
+ }
+
+ /**
+ *
+ * Assign all colors to their closest approximation and return an array of
+ * color indexes.
+ *
+ * Uses Floyd-Steinberg dithering, finding the closest known color and then
+ * spreading out the error over four leading pixels. Limits error to +/- 75
+ * percent in normalized L*a*b space.
+ *
+ * @param cells
+ * quantized color cells
+ * @param colorMap
+ * map of quantized rgb to its cell
+ * @return array of color indexes, one for each pixel
+ *
+ */
+ private int[] indexPixels(Lst<ColorCell> cells,
+ Map<Integer, ColorCell> colorMap) {
+ // We need a strip only width+2 wide to process all the errors.
+ // Errors are added to the next pixel and the next row's pixels
+ // only through p + width + 1:
+ // p +1
+ // +w-1 +w +w+1
+ // so including p as well, we need a total of width + 2 errors.
+ //
+ // as p moves through the pixels, we just use mod to cycle through
+ // this strip.
+ //
+ int w2 = width + 2;
+ P3[] errors = new P3[w2];
+ // We should replace, not overwrite, pixels
+ // as this may be the raw canvas.buf32.
+ int[] newPixels = new int[pixels.length];
+ P3 err = new P3();
+ P3 lab;
+ int rgb;
+ Map<Integer, ColorCell> nearestCell = new Hashtable<Integer, ColorCell>();
+ for (int i = 0, p = 0; i < height; ++i) {
+ boolean notLastRow = (i != height - 1);
+ for (int j = 0; j < width; ++j, p++) {
+ if (pixels[p] == backgroundColor) {
+ // leave as 0
+ continue;
+ }
+ P3 pe = errors[p % w2];
+ if (pe == null || pe.x == Float.MAX_VALUE) {
+ lab = null;
+ rgb = pixels[p];
+ } else {
+ lab = toLABnorm(pixels[p]);
+ err = pe;
+ // important not to round the clamp here -- full floating precision
+ err.x = clamp(err.x, -75, 75);
+ err.y = clamp(err.y, -75, 75);
+ err.z = clamp(err.z, -75, 75);
+ lab.add(err);
+ rgb = CU.colorPtToFFRGB(toRGB(lab));
+ }
+ Integer key = Integer.valueOf(rgb);
+ ColorCell cell = colorMap.get(key);
+ if (cell == null) {
+ // critical to generate normalized L*a*b from RGB here for nearestCell mapping.
+ // otherwise future RGB keys may match the wrong cell
+ lab = toLABnorm(rgb);
+ cell = nearestCell.get(key);
+ if (cell == null) {
+ // find nearest cell
+ float maxerr = Float.MAX_VALUE;
+ // skip 0 0 0
+ for (int ib = cells.size(); --ib >= 1;) {
+ ColorCell c = cells.get(ib);
+ err.sub2(lab, c.center);
+ float d = err.lengthSquared();
+ if (d < maxerr) {
+ maxerr = d;
+ cell = c;
+ }
+ }
+ nearestCell.put(key, cell);
+ }
+ if (floydSteinberg) {
+ // dither
+ err.sub2(lab, cell.center);
+ boolean notLastCol = (j < width - 1);
+ if (notLastCol)
+ addError(err, 7, errors, p + 1, w2);
+ if (notLastRow) {
+ if (j > 0)
+ addError(err, 3, errors, p + width - 1, w2);
+ addError(err, 5, errors, p + width, w2);
+ if (notLastCol)
+ addError(err, 1, errors, p + width + 1, w2);
+ }
+ }
+ err.x = Float.MAX_VALUE; // used; flag for resetting to 0
+ }
+ newPixels[p] = cell.index;
+ }
+ }
+ return newPixels;
+ }
+
+ private void addError(P3 err, int f, P3[] errors, int p, int w2) {
+ // GIMP will allow changing the background color.
+ if (pixels[p] == backgroundColor)
+ return;
+ p %= w2;
+ P3 errp = errors[p];
+ if (errp == null)
+ errp = errors[p] = new P3();
+ else if (errp.x == Float.MAX_VALUE) // reuse
+ errp.set(0, 0, 0);
+ errp.scaleAdd2(f / 16f, err, errp);
+ }
+
+ ///////////////////////// CIE L*a*b / XYZ / sRGB conversion methods /////////
+
+ // these could be static, but that just makes for more JavaScript code
+
+ protected P3 toLABnorm(int rgb) {
+ P3 lab = CU.colorPtFromInt(rgb, null);
+ rgbToXyz(lab, lab);
+ xyzToLab(lab, lab);
+ // normalize to 0-100
+ lab.y = (lab.y + 86.185f) / (98.254f + 86.185f) * 100f;
+ lab.z = (lab.z + 107.863f) / (94.482f + 107.863f) * 100f;
+ return lab;
+ }
+
+ protected P3 toRGB(P3 lab) {
+ P3 xyz = P3.newP(lab);
+ // normalized to 0-100
+ xyz.y = xyz.y / 100f * (98.254f + 86.185f) - 86.185f;
+ xyz.z = xyz.z / 100f * (94.482f + 107.863f) - 107.863f;
+ labToXyz(xyz, xyz);
+ return xyzToRgb(xyz, xyz);
+ }
+
+ private static M3 xyz2rgb;
+ private static M3 rgb2xyz;
+
+ static {
+ rgb2xyz = M3.newA9(new float[] { 0.4124f, 0.3576f, 0.1805f, 0.2126f,
+ 0.7152f, 0.0722f, 0.0193f, 0.1192f, 0.9505f });
+
+ xyz2rgb = M3.newA9(new float[] { 3.2406f, -1.5372f, -0.4986f, -0.9689f,
+ 1.8758f, 0.0415f, 0.0557f, -0.2040f, 1.0570f });
+ }
+
+ public P3 rgbToXyz(P3 rgb, P3 xyz) {
+ // http://en.wikipedia.org/wiki/CIE_1931_color_space
+ // http://rsb.info.nih.gov/ij/plugins/download/Color_Space_Converter.java
+ if (xyz == null)
+ xyz = new P3();
+ xyz.x = sxyz(rgb.x);
+ xyz.y = sxyz(rgb.y);
+ xyz.z = sxyz(rgb.z);
+ rgb2xyz.rotate(xyz);
+ return xyz;
+ }
+
+ private float sxyz(float x) {
+ x /= 255;
+ return (float) (x <= 0.04045 ? x / 12.92 : Math.pow(((x + 0.055) / 1.055),
+ 2.4)) * 100;
+ }
+
+ public P3 xyzToRgb(P3 xyz, P3 rgb) {
+ // http://en.wikipedia.org/wiki/CIE_1931_color_space
+ // http://rsb.info.nih.gov/ij/plugins/download/Color_Space_Converter.java
+ if (rgb == null)
+ rgb = new P3();
+ rgb.setT(xyz);
+ rgb.scale(0.01f);
+ xyz2rgb.rotate(rgb);
+ rgb.x = clamp(srgb(rgb.x), 0, 255);
+ rgb.y = clamp(srgb(rgb.y), 0, 255);
+ rgb.z = clamp(srgb(rgb.z), 0, 255);
+ return rgb;
+ }
+
+ private float srgb(float x) {
+ return (float) (x > 0.0031308f ? (1.055 * Math.pow(x, 1.0 / 2.4)) - 0.055
+ : x * 12.92) * 255;
+ }
+
+ public P3 xyzToLab(P3 xyz, P3 lab) {
+ // http://en.wikipedia.org/wiki/Lab_color_space
+ // http://rsb.info.nih.gov/ij/plugins/download/Color_Space_Converter.java
+ // Lab([0..100], [-86.185..98.254], [-107.863..94.482])
+ // XYZn = D65 = {95.0429, 100.0, 108.8900};
+ if (lab == null)
+ lab = new P3();
+ float x = flab(xyz.x / 95.0429f);
+ float y = flab(xyz.y / 100);
+ float z = flab(xyz.z / 108.89f);
+ lab.x = (116 * y) - 16;
+ lab.y = 500 * (x - y);
+ lab.z = 200 * (y - z);
+ return lab;
+ }
+
+ private float flab(float t) {
+ return (float) (t > 8.85645168E-3 /* (24/116)^3 */? Math.pow(t,
+ 0.333333333) : 7.78703704 /* 1/3*116/24*116/24 */* t + 0.137931034 /* 16/116 */
+ );
+ }
+
+ public P3 labToXyz(P3 lab, P3 xyz) {
+ // http://en.wikipedia.org/wiki/Lab_color_space
+ // http://rsb.info.nih.gov/ij/plugins/download/Color_Space_Converter.java
+ // XYZn = D65 = {95.0429, 100.0, 108.8900};
+ if (xyz == null)
+ xyz = new P3();
+
+ xyz.setT(lab);
+ float y = (xyz.x + 16) / 116;
+ float x = xyz.y / 500 + y;
+ float z = y - xyz.z / 200;
+ xyz.x = fxyz(x) * 95.0429f;
+ xyz.y = fxyz(y) * 100;
+ xyz.z = fxyz(z) * 108.89f;
+
+ return xyz;
+ }
+
+ private float fxyz(float t) {
+ return (float) (t > 0.206896552 /* (24/116) */? t * t * t
+ : 0.128418549 /* 3*24/116*24/116 */* (t - 0.137931034 /* 16/116 */));
+ }
+
+ private float clamp(float c, float min, float max) {
+ c = (c < min ? min : c > max ? max : c);
+ return (min == 0 ? Math.round(c) : c);
+ }
+
+ ///////////////////////// GifEncoder writing methods ////////////////////////
+
+ /**
+ * includes logical screen descriptor
+ *
+ * @throws IOException
+ */
+ private void writeHeader() throws IOException {
+ putString("GIF89a");
+ putWord(width);
+ putWord(height);
+ putByte(0); // no global color table -- using local instead
+ putByte(0); // no background
+ putByte(0); // no pixel aspect ratio given
+ }
+
+ private void writeGraphicControlExtension() {
+ if (isTransparent || delayTime100ths >= 0) {
+ putByte(0x21); // graphic control extension
+ putByte(0xf9); // graphic control label
+ putByte(4); // block size
+ putByte((isTransparent ? 9 : 0) | (delayTime100ths > 0 ? 2 : 0)); // packed bytes
+ putWord(delayTime100ths > 0 ? delayTime100ths : 0);
+ putByte(0); // transparent index
+ putByte(0); // end-of-block
+ }
+ }
+
+ // see http://www.vurdalakov.net/misc/gif/netscape-looping-application-extension
+ // +---------------+
+ // 0 | 0x21 | Extension Label
+ // +---------------+
+ // 1 | 0xFF | Application Extension Label
+ // +---------------+
+ // 2 | 0x0B | Block Size
+ // +---------------+
+ // 3 | |
+ // +- -+
+ // 4 | |
+ // +- -+
+ // 5 | |
+ // +- -+
+ // 6 | |
+ // +- NETSCAPE -+ Application Identifier (8 bytes)
+ // 7 | |
+ // +- -+
+ // 8 | |
+ // +- -+
+ // 9 | |
+ // +- -+
+ // 10 | |
+ // +---------------+
+ // 11 | |
+ // +- -+
+ // 12 | 2.0 | Application Authentication Code (3 bytes)
+ // +- -+
+ // 13 | |
+ // +===============+ --+
+ // 14 | 0x03 | Sub-block Data Size |
+ // +---------------+ |
+ // 15 | 0x01 | Sub-block ID |
+ // +---------------+ | Application Data Sub-block
+ // 16 | | |
+ // +- -+ Loop Count (2 bytes) |
+ // 17 | | |
+ // +===============+ --+
+ // 18 | 0x00 | Block Terminator
+ // +---------------+
+
+ private void writeNetscapeLoopExtension() {
+ putByte(0x21); // graphic control extension
+ putByte(0xff); // netscape loop extension
+ putByte(0x0B); // block size
+ putString("NETSCAPE2.0");
+ putByte(3);
+ putByte(1);
+ putWord(0); // loop indefinitely
+ putByte(0); // end-of-block
+
+ }
+
+ private int initCodeSize;
+ private int curpt;
+
+ private void writeImage() {
+ putByte(0x2C);
+ putWord(0); //left
+ putWord(0); //top
+ putWord(width);
+ putWord(height);
+
+ // <Packed Fields> = LISx xZZZ
+
+ // L Local Color Table Flag
+ // I Interlace Flag
+ // S Sort Flag
+ // x Reserved
+ // ZZZ Size of Local Color Table
+
+ int packedFields = 0x80 | (interlaced ? 0x40 : 0) | (bitsPerPixel - 1);
+ putByte(packedFields);
+ int colorMapSize = 1 << bitsPerPixel;
+ P3 p = new P3();
+ for (int i = 0; i < colorMapSize; i++) {
+ if (palette[i] != null)
+ p = palette[i];
+ putByte((int) p.x);
+ putByte((int) p.y);
+ putByte((int) p.z);
+ }
+ putByte(initCodeSize = (bitsPerPixel <= 1 ? 2 : bitsPerPixel));
+ compress();
+ putByte(0);
+ }
+
+ private void writeTrailer() {
+ // Write the GIF file terminator
+ putByte(0x3B);
+ }
+
+ ///// compression routines /////
+
+ private static final int EOF = -1;
+
+ // Return the next pixel from the image
+ private int nextPixel() {
+ if (countDown-- == 0)
+ return EOF;
+ int colorIndex = pixels[curpt];
+ // Bump the current X position
+ ++curx;
+ if (curx == width) {
+ // If we are at the end of a scan line, set curx back to the beginning
+ // If we are interlaced, bump the cury to the appropriate spot,
+ // otherwise, just increment it.
+ curx = 0;
+ if (interlaced)
+ updateY(INTERLACE_PARAMS[pass], INTERLACE_PARAMS[pass + 4]);
+ else
+ ++cury;
+ }
+ curpt = cury * width + curx;
+ return colorIndex & 0xff;
+ }
+
+ private static final int[] INTERLACE_PARAMS = { 8, 8, 4, 2, 4, 2, 1, 0 };
+
+ /**
+ *
+ * Group 1 : Every 8th. row, starting with row 0. (Pass 1)
+ *
+ * Group 2 : Every 8th. row, starting with row 4. (Pass 2)
+ *
+ * Group 3 : Every 4th. row, starting with row 2. (Pass 3)
+ *
+ * Group 4 : Every 2nd. row, starting with row 1. (Pass 4)
+ *
+ * @param yNext
+ * @param yNew
+ */
+ private void updateY(int yNext, int yNew) {
+ cury += yNext;
+ if (yNew >= 0 && cury >= height) {
+ cury = yNew;
+ ++pass;
+ }
+ }
+
+ // Write out a word to the GIF file
+ private void putWord(int w) {
+ putByte(w);
+ putByte(w >> 8);
+ }
+
+ // GIFCOMPR.C - GIF Image compression routines
+ //
+ // Lempel-Ziv compression based on 'compress'. GIF modifications by
+ // David Rowley (mgardi@watdcsu.waterloo.edu)
+
+ // General DEFINEs
+
+ private static final int BITS = 12;
+
+ private static final int HSIZE = 5003; // 80% occupancy
+
+ // GIF Image compression - modified 'compress'
+ //
+ // Based on: compress.c - File compression ala IEEE Computer, June 1984.
+ //
+ // By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
+ // Jim McKie (decvax!mcvax!jim)
+ // Steve Davies (decvax!vax135!petsd!peora!srd)
+ // Ken Turkowski (decvax!decwrl!turtlevax!ken)
+ // James A. Woods (decvax!ihnp4!ames!jaw)
+ // Joe Orost (decvax!vax135!petsd!joe)
+
+ private int nBits; // number of bits/code
+ private int maxbits = BITS; // user settable max # bits/code
+ private int maxcode; // maximum code, given n_bits
+ private int maxmaxcode = 1 << BITS; // should NEVER generate this code
+
+ private final static int MAXCODE(int nBits) {
+ return (1 << nBits) - 1;
+ }
+
+ private int[] htab = new int[HSIZE];
+ private int[] codetab = new int[HSIZE];
+
+ private int hsize = HSIZE; // for dynamic table sizing
+
+ private int freeEnt = 0; // first unused entry
+
+ // block compression parameters -- after all codes are used up,
+ // and compression rate changes, start over.
+ private boolean clearFlag = false;
+
+ // Algorithm: use open addressing double hashing (no chaining) on the
+ // prefix code / next character combination. We do a variant of Knuth's
+ // algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
+ // secondary probe. Here, the modular division first probe is gives way
+ // to a faster exclusive-or manipulation. Also do block compression with
+ // an adaptive reset, whereby the code table is cleared when the compression
+ // ratio decreases, but after the table fills. The variable-length output
+ // codes are re-sized at this point, and a special CLEAR code is generated
+ // for the decompressor. Late addition: construct the table according to
+ // file size for noticeable speed improvement on small files. Please direct
+ // questions about this implementation to ames!jaw.
+
+ private int clearCode;
+ private int EOFCode;
+
+ private int countDown;
+ private int pass = 0;
+ private int curx, cury;
+
+ private void compress() {
+
+ // Calculate number of bits we are expecting
+ countDown = width * height;
+
+ // Indicate which pass we are on (if interlace)
+ pass = 0;
+ // Set up the current x and y position
+ curx = 0;
+ cury = 0;
+
+ // Set up the necessary values
+ clearFlag = false;
+ nBits = initCodeSize + 1;
+ maxcode = MAXCODE(nBits);
+
+ clearCode = 1 << initCodeSize;
+ EOFCode = clearCode + 1;
+ freeEnt = clearCode + 2;
+
+ // Set up the 'byte output' routine
+ bufPt = 0;
+
+ int ent = nextPixel();
+
+ int hshift = 0;
+ int fcode;
+ for (fcode = hsize; fcode < 65536; fcode *= 2)
+ ++hshift;
+ hshift = 8 - hshift; // set hash code range bound
+
+ int hsizeReg = hsize;
+ clearHash(hsizeReg); // clear hash table
+
+ output(clearCode);
+
+ int c;
+ outer_loop: while ((c = nextPixel()) != EOF) {
+ fcode = (c << maxbits) + ent;
+ int i = (c << hshift) ^ ent; // xor hashing
+
+ if (htab[i] == fcode) {
+ ent = codetab[i];
+ continue;
+ } else if (htab[i] >= 0) // non-empty slot
+ {
+ int disp = hsizeReg - i; // secondary hash (after G. Knott)
+ if (i == 0)
+ disp = 1;
+ do {
+ if ((i -= disp) < 0)
+ i += hsizeReg;
+
+ if (htab[i] == fcode) {
+ ent = codetab[i];
+ continue outer_loop;
+ }
+ } while (htab[i] >= 0);
+ }
+ output(ent);
+ ent = c;
+ if (freeEnt < maxmaxcode) {
+ codetab[i] = freeEnt++; // code -> hashtable
+ htab[i] = fcode;
+ } else {
+ clearBlock();
+ }
+ }
+ // Put out the final code.
+ output(ent);
+ output(EOFCode);
+ }
+
+ // output
+ //
+ // Output the given code.
+ // Inputs:
+ // code: A n_bits-bit integer. If == -1, then EOF. This assumes
+ // that n_bits =< wordsize - 1.
+ // Outputs:
+ // Outputs code to the file.
+ // Assumptions:
+ // Chars are 8 bits long.
+ // Algorithm:
+ // Maintain a BITS character long buffer (so that 8 codes will
+ // fit in it exactly). Use the VAX insv instruction to insert each
+ // code in turn. When the buffer fills up empty it and start over.
+
+ private int curAccum = 0;
+ private int curBits = 0;
+
+ private int masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F,
+ 0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF,
+ 0x7FFF, 0xFFFF };
+
+ private void output(int code) {
+ curAccum &= masks[curBits];
+
+ if (curBits > 0)
+ curAccum |= (code << curBits);
+ else
+ curAccum = code;
+
+ curBits += nBits;
+
+ while (curBits >= 8) {
+ byteOut((byte) (curAccum & 0xff));
+ curAccum >>= 8;
+ curBits -= 8;
+ }
+
+ // If the next entry is going to be too big for the code size,
+ // then increase it, if possible.
+ if (freeEnt > maxcode || clearFlag) {
+ if (clearFlag) {
+ maxcode = MAXCODE(nBits = initCodeSize + 1);
+ clearFlag = false;
+ } else {
+ ++nBits;
+ if (nBits == maxbits)
+ maxcode = maxmaxcode;
+ else
+ maxcode = MAXCODE(nBits);
+ }
+ }
+
+ if (code == EOFCode) {
+ // At EOF, write the rest of the buffer.
+ while (curBits > 0) {
+ byteOut((byte) (curAccum & 0xff));
+ curAccum >>= 8;
+ curBits -= 8;
+ }
+ flushBytes();
+ }
+ }
+
+ // Clear out the hash table
+
+ // table clear for block compress
+ private void clearBlock() {
+ clearHash(hsize);
+ freeEnt = clearCode + 2;
+ clearFlag = true;
+
+ output(clearCode);
+ }
+
+ // reset code table
+ private void clearHash(int hsize) {
+ for (int i = 0; i < hsize; ++i)
+ htab[i] = -1;
+ }
+
+ // GIF-specific routines (byte array buffer)
+
+ // Number of bytes so far in this 'packet'
+ private int bufPt;
+
+ // Define the storage for the packet accumulator
+ final private byte[] buf = new byte[256];
+
+ // Add a byte to the end of the current packet, and if it is 254
+ // byte, flush the packet to disk.
+ private void byteOut(byte c) {
+ buf[bufPt++] = c;
+ if (bufPt >= 254)
+ flushBytes();
+ }
+
+ // Flush the packet to disk, and reset the accumulator
+ protected void flushBytes() {
+ if (bufPt > 0) {
+ putByte(bufPt);
+ out.write(buf, 0, bufPt);
+ byteCount += bufPt;
+ bufPt = 0;
+ }
+ }
+
+}