001: /*
002: * Copyright 2003 by Paulo Soares.
003: *
004: * The contents of this file are subject to the Mozilla Public License Version 1.1
005: * (the "License"); you may not use this file except in compliance with the License.
006: * You may obtain a copy of the License at http://www.mozilla.org/MPL/
007: *
008: * Software distributed under the License is distributed on an "AS IS" basis,
009: * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
010: * for the specific language governing rights and limitations under the License.
011: *
012: * The Original Code is 'iText, a free JAVA-PDF library'.
013: *
014: * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
015: * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
016: * All Rights Reserved.
017: * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
018: * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
019: *
020: * Contributor(s): all the names of the contributors are added in the source code
021: * where applicable.
022: *
023: * Alternatively, the contents of this file may be used under the terms of the
024: * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
025: * provisions of LGPL are applicable instead of those above. If you wish to
026: * allow use of your version of this file only under the terms of the LGPL
027: * License and not to allow others to use your version of this file under
028: * the MPL, indicate your decision by deleting the provisions above and
029: * replace them with the notice and other provisions required by the LGPL.
030: * If you do not delete the provisions above, a recipient may use your version
031: * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
032: *
033: * This library is free software; you can redistribute it and/or modify it
034: * under the terms of the MPL as stated above or under the terms of the GNU
035: * Library General Public License as published by the Free Software Foundation;
036: * either version 2 of the License, or any later version.
037: *
038: * This library is distributed in the hope that it will be useful, but WITHOUT
039: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
040: * FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
041: * details.
042: *
043: * If you didn't download this code from the following link, you should check if
044: * you aren't using an obsolete version:
045: * http://www.lowagie.com/iText/
046: */
047: package com.lowagie.text.pdf.codec;
048:
049: import java.io.BufferedInputStream;
050: import java.io.ByteArrayInputStream;
051: import java.io.DataInputStream;
052: import java.io.IOException;
053: import java.io.InputStream;
054: import java.net.URL;
055: import java.util.ArrayList;
056:
057: import com.lowagie.text.ExceptionConverter;
058: import com.lowagie.text.Image;
059: import com.lowagie.text.ImgRaw;
060: import com.lowagie.text.Utilities;
061: import com.lowagie.text.pdf.PdfArray;
062: import com.lowagie.text.pdf.PdfDictionary;
063: import com.lowagie.text.pdf.PdfName;
064: import com.lowagie.text.pdf.PdfNumber;
065: import com.lowagie.text.pdf.PdfString;
066:
067: /** Reads gif images of all types. All the images in a gif are read in the constructors
068: * and can be retrieved with other methods.
069: * @author Paulo Soares (psoares@consiste.pt)
070: */
071: public class GifImage {
072:
073: protected DataInputStream in;
074: protected int width; // full image width
075: protected int height; // full image height
076: protected boolean gctFlag; // global color table used
077:
078: protected int bgIndex; // background color index
079: protected int bgColor; // background color
080: protected int pixelAspect; // pixel aspect ratio
081:
082: protected boolean lctFlag; // local color table flag
083: protected boolean interlace; // interlace flag
084: protected int lctSize; // local color table size
085:
086: protected int ix, iy, iw, ih; // current image rectangle
087:
088: protected byte[] block = new byte[256]; // current data block
089: protected int blockSize = 0; // block size
090:
091: // last graphic control extension info
092: protected int dispose = 0; // 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
093: protected boolean transparency = false; // use transparent color
094: protected int delay = 0; // delay in milliseconds
095: protected int transIndex; // transparent color index
096:
097: protected static final int MaxStackSize = 4096; // max decoder pixel stack size
098:
099: // LZW decoder working arrays
100: protected short[] prefix;
101: protected byte[] suffix;
102: protected byte[] pixelStack;
103: protected byte[] pixels;
104:
105: protected byte m_out[];
106: protected int m_bpc;
107: protected int m_gbpc;
108: protected byte m_global_table[];
109: protected byte m_local_table[];
110: protected byte m_curr_table[];
111: protected int m_line_stride;
112: protected byte fromData[];
113: protected URL fromUrl;
114:
115: protected ArrayList frames = new ArrayList(); // frames read from current file
116:
117: /** Reads gif images from an URL.
118: * @param url the URL
119: * @throws IOException on error
120: */
121: public GifImage(URL url) throws IOException {
122: fromUrl = url;
123: InputStream is = null;
124: try {
125: is = url.openStream();
126: process(is);
127: } finally {
128: if (is != null) {
129: is.close();
130: }
131: }
132: }
133:
134: /** Reads gif images from a file.
135: * @param file the file
136: * @throws IOException on error
137: */
138: public GifImage(String file) throws IOException {
139: this (Utilities.toURL(file));
140: }
141:
142: /** Reads gif images from a byte array.
143: * @param data the byte array
144: * @throws IOException on error
145: */
146: public GifImage(byte data[]) throws IOException {
147: fromData = data;
148: InputStream is = null;
149: try {
150: is = new ByteArrayInputStream(data);
151: process(is);
152: } finally {
153: if (is != null) {
154: is.close();
155: }
156: }
157: }
158:
159: /** Reads gif images from a stream. The stream is not closed.
160: * @param is the stream
161: * @throws IOException on error
162: */
163: public GifImage(InputStream is) throws IOException {
164: process(is);
165: }
166:
167: /** Gets the number of frames the gif has.
168: * @return the number of frames the gif has
169: */
170: public int getFrameCount() {
171: return frames.size();
172: }
173:
174: /** Gets the image from a frame. The first frame is 1.
175: * @param frame the frame to get the image from
176: * @return the image
177: */
178: public Image getImage(int frame) {
179: GifFrame gf = (GifFrame) frames.get(frame - 1);
180: return gf.image;
181: }
182:
183: /** Gets the [x,y] position of the frame in reference to the
184: * logical screen.
185: * @param frame the frame
186: * @return the [x,y] position of the frame
187: */
188: public int[] getFramePosition(int frame) {
189: GifFrame gf = (GifFrame) frames.get(frame - 1);
190: return new int[] { gf.ix, gf.iy };
191:
192: }
193:
194: /** Gets the logical screen. The images may be smaller and placed
195: * in some position in this screen to playback some animation.
196: * No image will be be bigger that this.
197: * @return the logical screen dimensions as [x,y]
198: */
199: public int[] getLogicalScreen() {
200: return new int[] { width, height };
201: }
202:
203: void process(InputStream is) throws IOException {
204: in = new DataInputStream(new BufferedInputStream(is));
205: readHeader();
206: readContents();
207: if (frames.isEmpty())
208: throw new IOException(
209: "The file does not contain any valid image.");
210: }
211:
212: /**
213: * Reads GIF file header information.
214: */
215: protected void readHeader() throws IOException {
216: String id = "";
217: for (int i = 0; i < 6; i++)
218: id += (char) in.read();
219: if (!id.startsWith("GIF8")) {
220: throw new IOException("Gif signature nor found.");
221: }
222:
223: readLSD();
224: if (gctFlag) {
225: m_global_table = readColorTable(m_gbpc);
226: }
227: }
228:
229: /**
230: * Reads Logical Screen Descriptor
231: */
232: protected void readLSD() throws IOException {
233:
234: // logical screen size
235: width = readShort();
236: height = readShort();
237:
238: // packed fields
239: int packed = in.read();
240: gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
241: m_gbpc = (packed & 7) + 1;
242: bgIndex = in.read(); // background color index
243: pixelAspect = in.read(); // pixel aspect ratio
244: }
245:
246: /**
247: * Reads next 16-bit value, LSB first
248: */
249: protected int readShort() throws IOException {
250: // read 16-bit value, LSB first
251: return in.read() | (in.read() << 8);
252: }
253:
254: /**
255: * Reads next variable length block from input.
256: *
257: * @return number of bytes stored in "buffer"
258: */
259: protected int readBlock() throws IOException {
260: blockSize = in.read();
261: if (blockSize <= 0)
262: return blockSize = 0;
263: for (int k = 0; k < blockSize; ++k) {
264: int v = in.read();
265: if (v < 0) {
266: return blockSize = k;
267: }
268: block[k] = (byte) v;
269: }
270: return blockSize;
271: }
272:
273: protected byte[] readColorTable(int bpc) throws IOException {
274: int ncolors = 1 << bpc;
275: int nbytes = 3 * ncolors;
276: bpc = newBpc(bpc);
277: byte table[] = new byte[(1 << bpc) * 3];
278: in.readFully(table, 0, nbytes);
279: return table;
280: }
281:
282: static protected int newBpc(int bpc) {
283: switch (bpc) {
284: case 1:
285: case 2:
286: case 4:
287: break;
288: case 3:
289: return 4;
290: default:
291: return 8;
292: }
293: return bpc;
294: }
295:
296: protected void readContents() throws IOException {
297: // read GIF file content blocks
298: boolean done = false;
299: while (!done) {
300: int code = in.read();
301: switch (code) {
302:
303: case 0x2C: // image separator
304: readImage();
305: break;
306:
307: case 0x21: // extension
308: code = in.read();
309: switch (code) {
310:
311: case 0xf9: // graphics control extension
312: readGraphicControlExt();
313: break;
314:
315: case 0xff: // application extension
316: readBlock();
317: skip(); // don't care
318: break;
319:
320: default: // uninteresting extension
321: skip();
322: }
323: break;
324:
325: default:
326: done = true;
327: break;
328: }
329: }
330: }
331:
332: /**
333: * Reads next frame image
334: */
335: protected void readImage() throws IOException {
336: ix = readShort(); // (sub)image position & size
337: iy = readShort();
338: iw = readShort();
339: ih = readShort();
340:
341: int packed = in.read();
342: lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
343: interlace = (packed & 0x40) != 0; // 2 - interlace flag
344: // 3 - sort flag
345: // 4-5 - reserved
346: lctSize = 2 << (packed & 7); // 6-8 - local color table size
347: m_bpc = newBpc(m_gbpc);
348: if (lctFlag) {
349: m_curr_table = readColorTable((packed & 7) + 1); // read table
350: m_bpc = newBpc((packed & 7) + 1);
351: } else {
352: m_curr_table = m_global_table;
353: }
354: if (transparency && transIndex >= m_curr_table.length / 3)
355: transparency = false;
356: if (transparency && m_bpc == 1) { // Acrobat 5.05 doesn't like this combination
357: byte tp[] = new byte[12];
358: System.arraycopy(m_curr_table, 0, tp, 0, 6);
359: m_curr_table = tp;
360: m_bpc = 2;
361: }
362: boolean skipZero = decodeImageData(); // decode pixel data
363: if (!skipZero)
364: skip();
365:
366: Image img = null;
367: try {
368: img = new ImgRaw(iw, ih, 1, m_bpc, m_out);
369: PdfArray colorspace = new PdfArray();
370: colorspace.add(PdfName.INDEXED);
371: colorspace.add(PdfName.DEVICERGB);
372: int len = m_curr_table.length;
373: colorspace.add(new PdfNumber(len / 3 - 1));
374: colorspace.add(new PdfString(m_curr_table));
375: PdfDictionary ad = new PdfDictionary();
376: ad.put(PdfName.COLORSPACE, colorspace);
377: img.setAdditional(ad);
378: if (transparency) {
379: img
380: .setTransparency(new int[] { transIndex,
381: transIndex });
382: }
383: } catch (Exception e) {
384: throw new ExceptionConverter(e);
385: }
386: img.setOriginalType(Image.ORIGINAL_GIF);
387: img.setOriginalData(fromData);
388: img.setUrl(fromUrl);
389: GifFrame gf = new GifFrame();
390: gf.image = img;
391: gf.ix = ix;
392: gf.iy = iy;
393: frames.add(gf); // add image to frame list
394:
395: //resetFrame();
396:
397: }
398:
399: protected boolean decodeImageData() throws IOException {
400: int NullCode = -1;
401: int npix = iw * ih;
402: int available, clear, code_mask, code_size, end_of_information, in_code, old_code, bits, code, count, i, datum, data_size, first, top, bi;
403: boolean skipZero = false;
404:
405: if (prefix == null)
406: prefix = new short[MaxStackSize];
407: if (suffix == null)
408: suffix = new byte[MaxStackSize];
409: if (pixelStack == null)
410: pixelStack = new byte[MaxStackSize + 1];
411:
412: m_line_stride = (iw * m_bpc + 7) / 8;
413: m_out = new byte[m_line_stride * ih];
414: int pass = 1;
415: int inc = interlace ? 8 : 1;
416: int line = 0;
417: int xpos = 0;
418:
419: // Initialize GIF data stream decoder.
420:
421: data_size = in.read();
422: clear = 1 << data_size;
423: end_of_information = clear + 1;
424: available = clear + 2;
425: old_code = NullCode;
426: code_size = data_size + 1;
427: code_mask = (1 << code_size) - 1;
428: for (code = 0; code < clear; code++) {
429: prefix[code] = 0;
430: suffix[code] = (byte) code;
431: }
432:
433: // Decode GIF pixel stream.
434:
435: datum = bits = count = first = top = bi = 0;
436:
437: for (i = 0; i < npix;) {
438: if (top == 0) {
439: if (bits < code_size) {
440: // Load bytes until there are enough bits for a code.
441: if (count == 0) {
442: // Read a new data block.
443: count = readBlock();
444: if (count <= 0) {
445: skipZero = true;
446: break;
447: }
448: bi = 0;
449: }
450: datum += (((int) block[bi]) & 0xff) << bits;
451: bits += 8;
452: bi++;
453: count--;
454: continue;
455: }
456:
457: // Get the next code.
458:
459: code = datum & code_mask;
460: datum >>= code_size;
461: bits -= code_size;
462:
463: // Interpret the code
464:
465: if ((code > available) || (code == end_of_information))
466: break;
467: if (code == clear) {
468: // Reset decoder.
469: code_size = data_size + 1;
470: code_mask = (1 << code_size) - 1;
471: available = clear + 2;
472: old_code = NullCode;
473: continue;
474: }
475: if (old_code == NullCode) {
476: pixelStack[top++] = suffix[code];
477: old_code = code;
478: first = code;
479: continue;
480: }
481: in_code = code;
482: if (code == available) {
483: pixelStack[top++] = (byte) first;
484: code = old_code;
485: }
486: while (code > clear) {
487: pixelStack[top++] = suffix[code];
488: code = prefix[code];
489: }
490: first = ((int) suffix[code]) & 0xff;
491:
492: // Add a new string to the string table,
493:
494: if (available >= MaxStackSize)
495: break;
496: pixelStack[top++] = (byte) first;
497: prefix[available] = (short) old_code;
498: suffix[available] = (byte) first;
499: available++;
500: if (((available & code_mask) == 0)
501: && (available < MaxStackSize)) {
502: code_size++;
503: code_mask += available;
504: }
505: old_code = in_code;
506: }
507:
508: // Pop a pixel off the pixel stack.
509:
510: top--;
511: i++;
512:
513: setPixel(xpos, line, pixelStack[top]);
514: ++xpos;
515: if (xpos >= iw) {
516: xpos = 0;
517: line += inc;
518: if (line >= ih) {
519: if (interlace) {
520: do {
521: pass++;
522: switch (pass) {
523: case 2:
524: line = 4;
525: break;
526: case 3:
527: line = 2;
528: inc = 4;
529: break;
530: case 4:
531: line = 1;
532: inc = 2;
533: break;
534: default: // this shouldn't happen
535: line = ih - 1;
536: inc = 0;
537: }
538: } while (line >= ih);
539: } else {
540: line = ih - 1; // this shouldn't happen
541: inc = 0;
542: }
543: }
544: }
545: }
546: return skipZero;
547: }
548:
549: protected void setPixel(int x, int y, int v) {
550: if (m_bpc == 8) {
551: int pos = x + iw * y;
552: m_out[pos] = (byte) v;
553: } else {
554: int pos = m_line_stride * y + x / (8 / m_bpc);
555: int vout = v << (8 - m_bpc * (x % (8 / m_bpc)) - m_bpc);
556: m_out[pos] |= vout;
557: }
558: }
559:
560: /**
561: * Resets frame state for reading next image.
562: */
563: protected void resetFrame() {
564: // it does nothing in the pdf context
565: //boolean transparency = false;
566: //int delay = 0;
567: }
568:
569: /**
570: * Reads Graphics Control Extension values
571: */
572: protected void readGraphicControlExt() throws IOException {
573: in.read(); // block size
574: int packed = in.read(); // packed fields
575: dispose = (packed & 0x1c) >> 2; // disposal method
576: if (dispose == 0)
577: dispose = 1; // elect to keep old image if discretionary
578: transparency = (packed & 1) != 0;
579: delay = readShort() * 10; // delay in milliseconds
580: transIndex = in.read(); // transparent color index
581: in.read(); // block terminator
582: }
583:
584: /**
585: * Skips variable length blocks up to and including
586: * next zero length block.
587: */
588: protected void skip() throws IOException {
589: do {
590: readBlock();
591: } while (blockSize > 0);
592: }
593:
594: static class GifFrame {
595: Image image;
596: int ix;
597: int iy;
598: }
599: }
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