/* * Copyright 2003 by Paulo Soares. * * The contents of this file are subject to the Mozilla Public License Version 1.1 * (the "License"); you may not use this file except in compliance with the License. * You may obtain a copy of the License at http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the License. * * The Original Code is 'iText, a free JAVA-PDF library'. * * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie. * All Rights Reserved. * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved. * * Contributor(s): all the names of the contributors are added in the source code * where applicable. * * Alternatively, the contents of this file may be used under the terms of the * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the * provisions of LGPL are applicable instead of those above. If you wish to * allow use of your version of this file only under the terms of the LGPL * License and not to allow others to use your version of this file under * the MPL, indicate your decision by deleting the provisions above and * replace them with the notice and other provisions required by the LGPL. * If you do not delete the provisions above, a recipient may use your version * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE. * * This library is free software; you can redistribute it and/or modify it * under the terms of the MPL as stated above or under the terms of the GNU * Library General Public License as published by the Free Software Foundation; * either version 2 of the License, or 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 Library general Public License for more * details. * * If you didn't download this code from the following link, you should check if * you aren't using an obsolete version: * http://www.lowagie.com/iText/ * * * The original JAI codecs have the following license * * Copyright (c) 2001 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * -Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduct the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of Sun Microsystems, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE * POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that Software is not designed,licensed or intended for use in * the design, construction, operation or maintenance of any nuclear facility. */ package com.lowagie.text.pdf.codec; import java.awt.color.ICC_Profile; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.zip.Inflater; import java.util.zip.InflaterInputStream; import com.lowagie.text.ExceptionConverter; import com.lowagie.text.Image; import com.lowagie.text.ImgRaw; import com.lowagie.text.pdf.ByteBuffer; import com.lowagie.text.pdf.PdfArray; import com.lowagie.text.pdf.PdfDictionary; import com.lowagie.text.pdf.PdfLiteral; import com.lowagie.text.pdf.PdfName; import com.lowagie.text.pdf.PdfNumber; import com.lowagie.text.pdf.PdfObject; import com.lowagie.text.pdf.PdfReader; import com.lowagie.text.pdf.PdfString; /** Reads a PNG image. All types of PNG can be read. *

* It is based in part in the JAI codec. * * @author Paulo Soares (psoares@consiste.pt) */ public class PngImage { /** Some PNG specific values. */ public static final int[] PNGID = {137, 80, 78, 71, 13, 10, 26, 10}; /** A PNG marker. */ public static final String IHDR = "IHDR"; /** A PNG marker. */ public static final String PLTE = "PLTE"; /** A PNG marker. */ public static final String IDAT = "IDAT"; /** A PNG marker. */ public static final String IEND = "IEND"; /** A PNG marker. */ public static final String tRNS = "tRNS"; /** A PNG marker. */ public static final String pHYs = "pHYs"; /** A PNG marker. */ public static final String gAMA = "gAMA"; /** A PNG marker. */ public static final String cHRM = "cHRM"; /** A PNG marker. */ public static final String sRGB = "sRGB"; /** A PNG marker. */ public static final String iCCP = "iCCP"; private static final int TRANSFERSIZE = 4096; private static final int PNG_FILTER_NONE = 0; private static final int PNG_FILTER_SUB = 1; private static final int PNG_FILTER_UP = 2; private static final int PNG_FILTER_AVERAGE = 3; private static final int PNG_FILTER_PAETH = 4; private static final PdfName intents[] = {PdfName.PERCEPTUAL, PdfName.RELATIVECALORIMETRIC,PdfName.SATURATION,PdfName.ABSOLUTECALORIMETRIC}; InputStream is; DataInputStream dataStream; int width; int height; int bitDepth; int colorType; int compressionMethod; int filterMethod; int interlaceMethod; PdfDictionary additional = new PdfDictionary(); byte image[]; byte smask[]; byte trans[]; NewByteArrayOutputStream idat = new NewByteArrayOutputStream(); int dpiX; int dpiY; float XYRatio; boolean genBWMask; boolean palShades; int transRedGray = -1; int transGreen = -1; int transBlue = -1; int inputBands; int bytesPerPixel; // number of bytes per input pixel byte colorTable[]; float gamma = 1f; boolean hasCHRM = false; float xW, yW, xR, yR, xG, yG, xB, yB; PdfName intent; ICC_Profile icc_profile; /** Creates a new instance of PngImage */ PngImage(InputStream is) { this.is = is; } /** Reads a PNG from an url. * @param url the url * @throws IOException on error * @return the image */ public static Image getImage(URL url) throws IOException { InputStream is = null; try { is = url.openStream(); Image img = getImage(is); img.setUrl(url); return img; } finally { if (is != null) { is.close(); } } } /** Reads a PNG from a stream. * @param is the stream * @throws IOException on error * @return the image */ public static Image getImage(InputStream is) throws IOException { PngImage png = new PngImage(is); return png.getImage(); } /** Reads a PNG from a file. * @param file the file * @throws IOException on error * @return the image */ public static Image getImage(String file) throws IOException { return getImage(Image.toURL(file)); } /** Reads a PNG from a byte array. * @param data the byte array * @throws IOException on error * @return the image */ public static Image getImage(byte data[]) throws IOException { InputStream is = null; try { is = new ByteArrayInputStream(data); Image img = getImage(is); img.setOriginalData(data); return img; } finally { if (is != null) { is.close(); } } } boolean checkMarker(String s) { if (s.length() != 4) return false; for (int k = 0; k < 4; ++k) { char c = s.charAt(k); if ((c < 'a' || c > 'z') && (c < 'A' || c > 'Z')) return false; } return true; } void readPng() throws IOException { for (int i = 0; i < PNGID.length; i++) { if (PNGID[i] != is.read()) { throw new IOException("File is not a valid PNG."); } } byte buffer[] = new byte[TRANSFERSIZE]; while (true) { int len = getInt(is); String marker = getString(is); if (len < 0 || !checkMarker(marker)) throw new IOException("Corrupted PNG file."); if (IDAT.equals(marker)) { int size; while (len != 0) { size = is.read(buffer, 0, Math.min(len, TRANSFERSIZE)); if (size < 0) return; idat.write(buffer, 0, size); len -= size; } } else if (tRNS.equals(marker)) { switch (colorType) { case 0: if (len >= 2) { len -= 2; int gray = getWord(is); if (bitDepth == 16) transRedGray = gray; else additional.put(PdfName.MASK, new PdfLiteral("["+gray+" "+gray+"]")); } break; case 2: if (len >= 6) { len -= 6; int red = getWord(is); int green = getWord(is); int blue = getWord(is); if (bitDepth == 16) { transRedGray = red; transGreen = green; transBlue = blue; } else additional.put(PdfName.MASK, new PdfLiteral("["+red+" "+red+" "+green+" "+green+" "+blue+" "+blue+"]")); } break; case 3: if (len > 0) { trans = new byte[len]; for (int k = 0; k < len; ++k) trans[k] = (byte)is.read(); len = 0; } break; } Image.skip(is, len); } else if (IHDR.equals(marker)) { width = getInt(is); height = getInt(is); bitDepth = is.read(); colorType = is.read(); compressionMethod = is.read(); filterMethod = is.read(); interlaceMethod = is.read(); } else if (PLTE.equals(marker)) { if (colorType == 3) { PdfArray colorspace = new PdfArray(); colorspace.add(PdfName.INDEXED); colorspace.add(getColorspace()); colorspace.add(new PdfNumber(len / 3 - 1)); ByteBuffer colortable = new ByteBuffer(); while ((len--) > 0) { colortable.append_i(is.read()); } colorspace.add(new PdfString(colorTable = colortable.toByteArray())); additional.put(PdfName.COLORSPACE, colorspace); } else { Image.skip(is, len); } } else if (pHYs.equals(marker)) { int dx = getInt(is); int dy = getInt(is); int unit = is.read(); if (unit == 1) { dpiX = (int)((float)dx * 0.0254f); dpiY = (int)((float)dy * 0.0254f); } else { if (dy != 0) XYRatio = (float)dx / (float)dy; } } else if (cHRM.equals(marker)) { xW = (float)getInt(is) / 100000f; yW = (float)getInt(is) / 100000f; xR = (float)getInt(is) / 100000f; yR = (float)getInt(is) / 100000f; xG = (float)getInt(is) / 100000f; yG = (float)getInt(is) / 100000f; xB = (float)getInt(is) / 100000f; yB = (float)getInt(is) / 100000f; hasCHRM = !(Math.abs(xW)<0.0001f||Math.abs(yW)<0.0001f||Math.abs(xR)<0.0001f||Math.abs(yR)<0.0001f||Math.abs(xG)<0.0001f||Math.abs(yG)<0.0001f||Math.abs(xB)<0.0001f||Math.abs(yB)<0.0001f); } else if (sRGB.equals(marker)) { int ri = is.read(); intent = intents[ri]; gamma = 2.2f; xW = 0.3127f; yW = 0.329f; xR = 0.64f; yR = 0.33f; xG = 0.3f; yG = 0.6f; xB = 0.15f; yB = 0.06f; hasCHRM = true; } else if (gAMA.equals(marker)) { int gm = getInt(is); if (gm != 0) { gamma = 100000f / (float)gm; if (!hasCHRM) { xW = 0.3127f; yW = 0.329f; xR = 0.64f; yR = 0.33f; xG = 0.3f; yG = 0.6f; xB = 0.15f; yB = 0.06f; hasCHRM = true; } } } else if (iCCP.equals(marker)) { do { --len; } while (is.read() != 0); is.read(); --len; byte icccom[] = new byte[len]; int p = 0; while (len > 0) { int r = is.read(icccom, p, len); if (r < 0) throw new IOException("Premature end of file."); p += r; len -= r; } byte iccp[] = PdfReader.FlateDecode(icccom, true); icccom = null; try { icc_profile = ICC_Profile.getInstance(iccp); } catch (Exception e) { icc_profile = null; } } else if (IEND.equals(marker)) { break; } else { Image.skip(is, len); } Image.skip(is, 4); } } PdfObject getColorspace() { if (icc_profile != null) { if ((colorType & 2) == 0) return PdfName.DEVICEGRAY; else return PdfName.DEVICERGB; } if (gamma == 1f && !hasCHRM) { if ((colorType & 2) == 0) return PdfName.DEVICEGRAY; else return PdfName.DEVICERGB; } else { PdfArray array = new PdfArray(); PdfDictionary dic = new PdfDictionary(); if ((colorType & 2) == 0) { if (gamma == 1f) return PdfName.DEVICEGRAY; array.add(PdfName.CALGRAY); dic.put(PdfName.GAMMA, new PdfNumber(gamma)); dic.put(PdfName.WHITEPOINT, new PdfLiteral("[1 1 1]")); array.add(dic); } else { PdfObject wp = new PdfLiteral("[1 1 1]"); array.add(PdfName.CALRGB); if (gamma != 1f) { PdfArray gm = new PdfArray(); PdfNumber n = new PdfNumber(gamma); gm.add(n); gm.add(n); gm.add(n); dic.put(PdfName.GAMMA, gm); } if (hasCHRM) { float z = yW*((xG-xB)*yR-(xR-xB)*yG+(xR-xG)*yB); float YA = yR*((xG-xB)*yW-(xW-xB)*yG+(xW-xG)*yB)/z; float XA = YA*xR/yR; float ZA = YA*((1-xR)/yR-1); float YB = -yG*((xR-xB)*yW-(xW-xB)*yR+(xW-xR)*yB)/z; float XB = YB*xG/yG; float ZB = YB*((1-xG)/yG-1); float YC = yB*((xR-xG)*yW-(xW-xG)*yW+(xW-xR)*yG)/z; float XC = YC*xB/yB; float ZC = YC*((1-xB)/yB-1); float XW = XA+XB+XC; float YW = 1;//YA+YB+YC; float ZW = ZA+ZB+ZC; PdfArray wpa = new PdfArray(); wpa.add(new PdfNumber(XW)); wpa.add(new PdfNumber(YW)); wpa.add(new PdfNumber(ZW)); wp = wpa; PdfArray matrix = new PdfArray(); matrix.add(new PdfNumber(XA)); matrix.add(new PdfNumber(YA)); matrix.add(new PdfNumber(ZA)); matrix.add(new PdfNumber(XB)); matrix.add(new PdfNumber(YB)); matrix.add(new PdfNumber(ZB)); matrix.add(new PdfNumber(XC)); matrix.add(new PdfNumber(YC)); matrix.add(new PdfNumber(ZC)); dic.put(PdfName.MATRIX, matrix); } dic.put(PdfName.WHITEPOINT, wp); array.add(dic); } return array; } } Image getImage() throws IOException { readPng(); try { int pal0 = 0; int palIdx = 0; palShades = false; if (trans != null) { for (int k = 0; k < trans.length; ++k) { int n = trans[k] & 0xff; if (n == 0) { ++pal0; palIdx = k; } if (n != 0 && n != 255) { palShades = true; break; } } } if ((colorType & 4) != 0) palShades = true; genBWMask = (!palShades && (pal0 > 1 || transRedGray >= 0)); if (!palShades && !genBWMask && pal0 == 1) { additional.put(PdfName.MASK, new PdfLiteral("["+palIdx+" "+palIdx+"]")); } boolean needDecode = (interlaceMethod == 1) || (bitDepth == 16) || ((colorType & 4) != 0) || palShades || genBWMask; switch (colorType) { case 0: inputBands = 1; break; case 2: inputBands = 3; break; case 3: inputBands = 1; break; case 4: inputBands = 2; break; case 6: inputBands = 4; break; } if (needDecode) decodeIdat(); int components = inputBands; if ((colorType & 4) != 0) --components; int bpc = bitDepth; if (bpc == 16) bpc = 8; Image img; if (image != null) img = Image.getInstance(width, height, components, bpc, image); else { img = new ImgRaw(width, height, components, bpc, idat.toByteArray()); img.setDeflated(true); PdfDictionary decodeparms = new PdfDictionary(); decodeparms.put(PdfName.BITSPERCOMPONENT, new PdfNumber(bitDepth)); decodeparms.put(PdfName.PREDICTOR, new PdfNumber(15)); decodeparms.put(PdfName.COLUMNS, new PdfNumber(width)); decodeparms.put(PdfName.COLORS, new PdfNumber((colorType == 3 || (colorType & 2) == 0) ? 1 : 3)); additional.put(PdfName.DECODEPARMS, decodeparms); } if (additional.get(PdfName.COLORSPACE) == null) additional.put(PdfName.COLORSPACE, getColorspace()); if (intent != null) additional.put(PdfName.INTENT, intent); if (additional.size() > 0) img.setAdditional(additional); if (icc_profile != null) img.tagICC(icc_profile); if (palShades) { Image im2 = Image.getInstance(width, height, 1, 8, smask); im2.makeMask(); img.setImageMask(im2); } if (genBWMask) { Image im2 = Image.getInstance(width, height, 1, 1, smask); im2.makeMask(); img.setImageMask(im2); } img.setDpi(dpiX, dpiY); img.setXYRatio(XYRatio); img.setOriginalType(Image.ORIGINAL_PNG); return img; } catch (Exception e) { throw new ExceptionConverter(e); } } void decodeIdat() { int nbitDepth = bitDepth; if (nbitDepth == 16) nbitDepth = 8; int size = -1; bytesPerPixel = (bitDepth == 16) ? 2 : 1; switch (colorType) { case 0: size = (nbitDepth * width + 7) / 8 * height; break; case 2: size = width * 3 * height; bytesPerPixel *= 3; break; case 3: if (interlaceMethod == 1) size = (nbitDepth * width + 7) / 8 * height; bytesPerPixel = 1; break; case 4: size = width * height; bytesPerPixel *= 2; break; case 6: size = width * 3 * height; bytesPerPixel *= 4; break; } if (size >= 0) image = new byte[size]; if (palShades) smask = new byte[width * height]; else if (genBWMask) smask = new byte[(width + 7) / 8 * height]; ByteArrayInputStream bai = new ByteArrayInputStream(idat.getBuf(), 0, idat.size()); InputStream infStream = new InflaterInputStream(bai, new Inflater()); dataStream = new DataInputStream(infStream); if (interlaceMethod != 1) { decodePass(0, 0, 1, 1, width, height); } else { decodePass(0, 0, 8, 8, (width + 7)/8, (height + 7)/8); decodePass(4, 0, 8, 8, (width + 3)/8, (height + 7)/8); decodePass(0, 4, 4, 8, (width + 3)/4, (height + 3)/8); decodePass(2, 0, 4, 4, (width + 1)/4, (height + 3)/4); decodePass(0, 2, 2, 4, (width + 1)/2, (height + 1)/4); decodePass(1, 0, 2, 2, width/2, (height + 1)/2); decodePass(0, 1, 1, 2, width, height/2); } } void decodePass( int xOffset, int yOffset, int xStep, int yStep, int passWidth, int passHeight) { if ((passWidth == 0) || (passHeight == 0)) { return; } int bytesPerRow = (inputBands*passWidth*bitDepth + 7)/8; byte[] curr = new byte[bytesPerRow]; byte[] prior = new byte[bytesPerRow]; // Decode the (sub)image row-by-row int srcY, dstY; for (srcY = 0, dstY = yOffset; srcY < passHeight; srcY++, dstY += yStep) { // Read the filter type byte and a row of data int filter = 0; try { filter = dataStream.read(); dataStream.readFully(curr, 0, bytesPerRow); } catch (Exception e) { // empty on purpose } switch (filter) { case PNG_FILTER_NONE: break; case PNG_FILTER_SUB: decodeSubFilter(curr, bytesPerRow, bytesPerPixel); break; case PNG_FILTER_UP: decodeUpFilter(curr, prior, bytesPerRow); break; case PNG_FILTER_AVERAGE: decodeAverageFilter(curr, prior, bytesPerRow, bytesPerPixel); break; case PNG_FILTER_PAETH: decodePaethFilter(curr, prior, bytesPerRow, bytesPerPixel); break; default: // Error -- uknown filter type throw new RuntimeException("PNG filter unknown."); } processPixels(curr, xOffset, xStep, dstY, passWidth); // Swap curr and prior byte[] tmp = prior; prior = curr; curr = tmp; } } void processPixels(byte curr[], int xOffset, int step, int y, int width) { int srcX, dstX; int out[] = getPixel(curr); int sizes = 0; switch (colorType) { case 0: case 3: case 4: sizes = 1; break; case 2: case 6: sizes = 3; break; } if (image != null) { dstX = xOffset; int yStride = (sizes*this.width*(bitDepth == 16 ? 8 : bitDepth)+ 7)/8; for (srcX = 0; srcX < width; srcX++) { setPixel(image, out, inputBands * srcX, sizes, dstX, y, bitDepth, yStride); dstX += step; } } if (palShades) { if ((colorType & 4) != 0) { if (bitDepth == 16) { for (int k = 0; k < width; ++k) out[k * inputBands + sizes] >>>= 8; } int yStride = this.width; dstX = xOffset; for (srcX = 0; srcX < width; srcX++) { setPixel(smask, out, inputBands * srcX + sizes, 1, dstX, y, 8, yStride); dstX += step; } } else { //colorType 3 int yStride = this.width; int v[] = new int[1]; dstX = xOffset; for (srcX = 0; srcX < width; srcX++) { int idx = out[srcX]; if (idx < trans.length) v[0] = trans[idx]; setPixel(smask, v, 0, 1, dstX, y, 8, yStride); dstX += step; } } } else if (genBWMask) { switch (colorType) { case 3: { int yStride = (this.width + 7) / 8; int v[] = new int[1]; dstX = xOffset; for (srcX = 0; srcX < width; srcX++) { int idx = out[srcX]; if (idx < trans.length) v[0] = (trans[idx] == 0 ? 1 : 0); setPixel(smask, v, 0, 1, dstX, y, 1, yStride); dstX += step; } break; } case 0: { int yStride = (this.width + 7) / 8; int v[] = new int[1]; dstX = xOffset; for (srcX = 0; srcX < width; srcX++) { int g = out[srcX]; v[0] = (g == transRedGray ? 1 : 0); setPixel(smask, v, 0, 1, dstX, y, 1, yStride); dstX += step; } break; } case 2: { int yStride = (this.width + 7) / 8; int v[] = new int[1]; dstX = xOffset; for (srcX = 0; srcX < width; srcX++) { int markRed = inputBands * srcX; v[0] = (out[markRed] == transRedGray && out[markRed + 1] == transGreen && out[markRed + 2] == transBlue ? 1 : 0); setPixel(smask, v, 0, 1, dstX, y, 1, yStride); dstX += step; } break; } } } } static int getPixel(byte image[], int x, int y, int bitDepth, int bytesPerRow) { if (bitDepth == 8) { int pos = bytesPerRow * y + x; return image[pos] & 0xff; } else { int pos = bytesPerRow * y + x / (8 / bitDepth); int v = image[pos] >> (8 - bitDepth * (x % (8 / bitDepth))- bitDepth); return v & ((1 << bitDepth) - 1); } } static void setPixel(byte image[], int data[], int offset, int size, int x, int y, int bitDepth, int bytesPerRow) { if (bitDepth == 8) { int pos = bytesPerRow * y + size * x; for (int k = 0; k < size; ++k) image[pos + k] = (byte)data[k + offset]; } else if (bitDepth == 16) { int pos = bytesPerRow * y + size * x; for (int k = 0; k < size; ++k) image[pos + k] = (byte)(data[k + offset] >>> 8); } else { int pos = bytesPerRow * y + x / (8 / bitDepth); int v = data[offset] << (8 - bitDepth * (x % (8 / bitDepth))- bitDepth); image[pos] |= v; } } int[] getPixel(byte curr[]) { switch (bitDepth) { case 8: { int out[] = new int[curr.length]; for (int k = 0; k < out.length; ++k) out[k] = curr[k] & 0xff; return out; } case 16: { int out[] = new int[curr.length / 2]; for (int k = 0; k < out.length; ++k) out[k] = ((curr[k * 2] & 0xff) << 8) + (curr[k * 2 + 1] & 0xff); return out; } default: { int out[] = new int[curr.length * 8 / bitDepth]; int idx = 0; int passes = 8 / bitDepth; int mask = (1 << bitDepth) - 1; for (int k = 0; k < curr.length; ++k) { for (int j = passes - 1; j >= 0; --j) { out[idx++] = (curr[k] >>> (bitDepth * j)) & mask; } } return out; } } } private static void decodeSubFilter(byte[] curr, int count, int bpp) { for (int i = bpp; i < count; i++) { int val; val = curr[i] & 0xff; val += curr[i - bpp] & 0xff; curr[i] = (byte)val; } } private static void decodeUpFilter(byte[] curr, byte[] prev, int count) { for (int i = 0; i < count; i++) { int raw = curr[i] & 0xff; int prior = prev[i] & 0xff; curr[i] = (byte)(raw + prior); } } private static void decodeAverageFilter(byte[] curr, byte[] prev, int count, int bpp) { int raw, priorPixel, priorRow; for (int i = 0; i < bpp; i++) { raw = curr[i] & 0xff; priorRow = prev[i] & 0xff; curr[i] = (byte)(raw + priorRow/2); } for (int i = bpp; i < count; i++) { raw = curr[i] & 0xff; priorPixel = curr[i - bpp] & 0xff; priorRow = prev[i] & 0xff; curr[i] = (byte)(raw + (priorPixel + priorRow)/2); } } private static int paethPredictor(int a, int b, int c) { int p = a + b - c; int pa = Math.abs(p - a); int pb = Math.abs(p - b); int pc = Math.abs(p - c); if ((pa <= pb) && (pa <= pc)) { return a; } else if (pb <= pc) { return b; } else { return c; } } private static void decodePaethFilter(byte[] curr, byte[] prev, int count, int bpp) { int raw, priorPixel, priorRow, priorRowPixel; for (int i = 0; i < bpp; i++) { raw = curr[i] & 0xff; priorRow = prev[i] & 0xff; curr[i] = (byte)(raw + priorRow); } for (int i = bpp; i < count; i++) { raw = curr[i] & 0xff; priorPixel = curr[i - bpp] & 0xff; priorRow = prev[i] & 0xff; priorRowPixel = prev[i - bpp] & 0xff; curr[i] = (byte)(raw + paethPredictor(priorPixel, priorRow, priorRowPixel)); } } static class NewByteArrayOutputStream extends ByteArrayOutputStream { public byte[] getBuf() { return buf; } } /** * Gets an int from an InputStream. * * @param is an InputStream * @return the value of an int */ public static final int getInt(InputStream is) throws IOException { return (is.read() << 24) + (is.read() << 16) + (is.read() << 8) + is.read(); } /** * Gets a word from an InputStream. * * @param is an InputStream * @return the value of an int */ public static final int getWord(InputStream is) throws IOException { return (is.read() << 8) + is.read(); } /** * Gets a String from an InputStream. * * @param is an InputStream * @return the value of an int */ public static final String getString(InputStream is) throws IOException { StringBuffer buf = new StringBuffer(); for (int i = 0; i < 4; i++) { buf.append((char)is.read()); } return buf.toString(); } }