Initial Commit
This commit is contained in:
597
iTechSharp/iTextSharp/text/pdf/codec/GifImage.cs
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597
iTechSharp/iTextSharp/text/pdf/codec/GifImage.cs
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using System;
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using System.Net;
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using System.IO;
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using System.Collections;
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using iTextSharp.text;
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using iTextSharp.text.pdf;
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/*
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* Copyright 2003 by Paulo Soares.
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*
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* The contents of this file are subject to the Mozilla Public License Version 1.1
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* (the "License"); you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License isp distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the License.
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*
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* The Original Code isp 'iText, a free JAVA-PDF library'.
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*
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* The Initial Developer of the Original Code isp Bruno Lowagie. Portions created by
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* the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
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* All Rights Reserved.
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* Co-Developer of the code isp Paulo Soares. Portions created by the Co-Developer
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* are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
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*
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* Contributor(s): all the names of the contributors are added in the source code
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* where applicable.
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*
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* Alternatively, the contents of this file may be used under the terms of the
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* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
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* provisions of LGPL are applicable instead of those above. If you wish to
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* allow use of your version of this file only under the terms of the LGPL
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* License and not to allow others to use your version of this file under
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* the MPL, indicate your decision by deleting the provisions above and
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* replace them with the notice and other provisions required by the LGPL.
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* If you do not delete the provisions above, a recipient may use your version
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* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
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*
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* This library isp free software; you can redistribute it and/or modify it
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* under the terms of the MPL as stated above or under the terms of the GNU
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* Library General Public License as published by the Free Software Foundation;
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* either version 2 of the License, or any later version.
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*
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* This library isp distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
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* details.
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*
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* If you didn't download this code from the following link, you should check if
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* you aren't using an obsolete version:
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* http://www.lowagie.com/iText/
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*/
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namespace iTextSharp.text.pdf.codec {
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/** Reads gif images of all types. All the images in a gif are read in the constructors
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* and can be retrieved with other methods.
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* @author Paulo Soares (psoares@consiste.pt)
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*/
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public class GifImage {
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protected Stream inp;
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protected int width; // full image width
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protected int height; // full image height
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protected bool gctFlag; // global color table used
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protected int bgIndex; // background color index
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protected int bgColor; // background color
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protected int pixelAspect; // pixel aspect ratio
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protected bool lctFlag; // local color table flag
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protected bool interlace; // interlace flag
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protected int lctSize; // local color table size
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protected int ix, iy, iw, ih; // current image rectangle
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protected byte[] block = new byte[256]; // current data block
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protected int blockSize = 0; // block size
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// last graphic control extension info
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protected int dispose = 0; // 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
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protected bool transparency = false; // use transparent color
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protected int delay = 0; // delay in milliseconds
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protected int transIndex; // transparent color index
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protected const int MaxStackSize = 4096; // max decoder pixel stack size
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// LZW decoder working arrays
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protected short[] prefix;
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protected byte[] suffix;
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protected byte[] pixelStack;
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protected byte[] pixels;
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protected byte[] m_out;
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protected int m_bpc;
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protected int m_gbpc;
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protected byte[] m_global_table;
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protected byte[] m_local_table;
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protected byte[] m_curr_table;
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protected int m_line_stride;
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protected byte[] fromData;
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protected Uri fromUrl;
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protected ArrayList frames = new ArrayList(); // frames read from current file
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/** Reads gif images from an URL.
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* @param url the URL
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* @throws IOException on error
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*/
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public GifImage(Uri url) {
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fromUrl = url;
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Stream isp = null;
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try {
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isp = WebRequest.Create(url).GetResponse().GetResponseStream();
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Process(isp);
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}
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finally {
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if (isp != null) {
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isp.Close();
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}
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}
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}
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/** Reads gif images from a file.
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* @param file the file
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* @throws IOException on error
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*/
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public GifImage(String file) : this(Utilities.ToURL(file)) {
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}
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/** Reads gif images from a byte array.
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* @param data the byte array
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* @throws IOException on error
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*/
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public GifImage(byte[] data) {
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fromData = data;
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Stream isp = null;
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try {
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isp = new MemoryStream(data);
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Process(isp);
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}
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finally {
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if (isp != null) {
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isp.Close();
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}
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}
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}
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/** Reads gif images from a stream. The stream isp not closed.
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* @param isp the stream
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* @throws IOException on error
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*/
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public GifImage(Stream isp) {
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Process(isp);
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}
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/** Gets the number of frames the gif has.
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* @return the number of frames the gif has
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*/
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public int GetFrameCount() {
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return frames.Count;
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}
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/** Gets the image from a frame. The first frame isp 1.
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* @param frame the frame to get the image from
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* @return the image
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*/
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public Image GetImage(int frame) {
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GifFrame gf = (GifFrame)frames[frame - 1];
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return gf.image;
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}
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/** Gets the [x,y] position of the frame in reference to the
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* logical screen.
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* @param frame the frame
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* @return the [x,y] position of the frame
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*/
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public int[] GetFramePosition(int frame) {
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GifFrame gf = (GifFrame)frames[frame - 1];
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return new int[]{gf.ix, gf.iy};
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}
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/** Gets the logical screen. The images may be smaller and placed
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* in some position in this screen to playback some animation.
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* No image will be be bigger that this.
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* @return the logical screen dimensions as [x,y]
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*/
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public int[] GetLogicalScreen() {
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return new int[]{width, height};
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}
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internal void Process(Stream isp) {
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inp = new BufferedStream(isp);
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ReadHeader();
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ReadContents();
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if (frames.Count == 0)
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throw new IOException("The file does not contain any valid image.");
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}
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/**
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* Reads GIF file header information.
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*/
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protected void ReadHeader() {
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String id = "";
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for (int i = 0; i < 6; i++)
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id += (char)inp.ReadByte();
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if (!id.StartsWith("GIF8")) {
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throw new IOException("Gif signature nor found.");
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}
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ReadLSD();
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if (gctFlag) {
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m_global_table = ReadColorTable(m_gbpc);
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}
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}
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/**
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* Reads Logical Screen Descriptor
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*/
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protected void ReadLSD() {
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// logical screen size
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width = ReadShort();
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height = ReadShort();
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// packed fields
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int packed = inp.ReadByte();
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gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
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m_gbpc = (packed & 7) + 1;
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bgIndex = inp.ReadByte(); // background color index
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pixelAspect = inp.ReadByte(); // pixel aspect ratio
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}
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/**
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* Reads next 16-bit value, LSB first
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*/
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protected int ReadShort() {
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// read 16-bit value, LSB first
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return inp.ReadByte() | (inp.ReadByte() << 8);
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}
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/**
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* Reads next variable length block from input.
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*
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* @return number of bytes stored in "buffer"
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*/
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protected int ReadBlock() {
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blockSize = inp.ReadByte();
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if (blockSize <= 0)
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return blockSize = 0;
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for (int k = 0; k < blockSize; ++k) {
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int v = inp.ReadByte();
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if (v < 0) {
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return blockSize = k;
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}
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block[k] = (byte)v;
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}
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return blockSize;
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}
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protected byte[] ReadColorTable(int bpc) {
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int ncolors = 1 << bpc;
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int nbytes = 3*ncolors;
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bpc = NewBpc(bpc);
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byte[] table = new byte[(1 << bpc) * 3];
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ReadFully(table, 0, nbytes);
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return table;
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}
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static protected int NewBpc(int bpc) {
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switch (bpc) {
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case 1:
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case 2:
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case 4:
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break;
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case 3:
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return 4;
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default:
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return 8;
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}
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return bpc;
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}
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protected void ReadContents() {
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// read GIF file content blocks
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bool done = false;
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while (!done) {
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int code = inp.ReadByte();
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switch (code) {
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case 0x2C: // image separator
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ReadImage();
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break;
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case 0x21: // extension
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code = inp.ReadByte();
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switch (code) {
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case 0xf9: // graphics control extension
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ReadGraphicControlExt();
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break;
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case 0xff: // application extension
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ReadBlock();
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Skip(); // don't care
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break;
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default: // uninteresting extension
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Skip();
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break;
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}
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break;
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default:
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done = true;
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break;
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}
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}
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}
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/**
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* Reads next frame image
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*/
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protected void ReadImage() {
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ix = ReadShort(); // (sub)image position & size
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iy = ReadShort();
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iw = ReadShort();
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ih = ReadShort();
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int packed = inp.ReadByte();
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lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
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interlace = (packed & 0x40) != 0; // 2 - interlace flag
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// 3 - sort flag
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// 4-5 - reserved
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lctSize = 2 << (packed & 7); // 6-8 - local color table size
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m_bpc = NewBpc(m_gbpc);
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if (lctFlag) {
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m_curr_table = ReadColorTable((packed & 7) + 1); // read table
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m_bpc = NewBpc((packed & 7) + 1);
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}
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else {
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m_curr_table = m_global_table;
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}
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if (transparency && transIndex >= m_curr_table.Length / 3)
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transparency = false;
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if (transparency && m_bpc == 1) { // Acrobat 5.05 doesn't like this combination
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byte[] tp = new byte[12];
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Array.Copy(m_curr_table, 0, tp, 0, 6);
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m_curr_table = tp;
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m_bpc = 2;
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}
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bool skipZero = DecodeImageData(); // decode pixel data
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if (!skipZero)
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Skip();
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Image img = null;
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img = new ImgRaw(iw, ih, 1, m_bpc, m_out);
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PdfArray colorspace = new PdfArray();
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colorspace.Add(PdfName.INDEXED);
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colorspace.Add(PdfName.DEVICERGB);
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int len = m_curr_table.Length;
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colorspace.Add(new PdfNumber(len / 3 - 1));
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colorspace.Add(new PdfString(m_curr_table));
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PdfDictionary ad = new PdfDictionary();
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ad.Put(PdfName.COLORSPACE, colorspace);
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img.Additional = ad;
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if (transparency) {
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img.Transparency = new int[]{transIndex, transIndex};
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}
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img.OriginalType = Image.ORIGINAL_GIF;
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img.OriginalData = fromData;
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img.Url = fromUrl;
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GifFrame gf = new GifFrame();
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gf.image = img;
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gf.ix = ix;
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gf.iy = iy;
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frames.Add(gf); // add image to frame list
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//ResetFrame();
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}
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protected bool DecodeImageData() {
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int NullCode = -1;
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int npix = iw * ih;
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int available, clear, code_mask, code_size, end_of_information, in_code, old_code,
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bits, code, count, i, datum, data_size, first, top, bi;
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bool skipZero = false;
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if (prefix == null)
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prefix = new short[MaxStackSize];
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if (suffix == null)
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suffix = new byte[MaxStackSize];
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if (pixelStack == null)
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pixelStack = new byte[MaxStackSize+1];
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m_line_stride = (iw * m_bpc + 7) / 8;
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m_out = new byte[m_line_stride * ih];
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int pass = 1;
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int inc = interlace ? 8 : 1;
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int line = 0;
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int xpos = 0;
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// Initialize GIF data stream decoder.
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data_size = inp.ReadByte();
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clear = 1 << data_size;
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end_of_information = clear + 1;
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available = clear + 2;
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old_code = NullCode;
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code_size = data_size + 1;
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code_mask = (1 << code_size) - 1;
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for (code = 0; code < clear; code++) {
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prefix[code] = 0;
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suffix[code] = (byte) code;
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}
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// Decode GIF pixel stream.
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datum = bits = count = first = top = bi = 0;
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for (i = 0; i < npix; ) {
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if (top == 0) {
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if (bits < code_size) {
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// Load bytes until there are enough bits for a code.
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if (count == 0) {
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// Read a new data block.
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count = ReadBlock();
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if (count <= 0) {
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skipZero = true;
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break;
|
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}
|
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bi = 0;
|
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}
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datum += (((int) block[bi]) & 0xff) << bits;
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bits += 8;
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bi++;
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count--;
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continue;
|
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}
|
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// Get the next code.
|
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code = datum & code_mask;
|
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datum >>= code_size;
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bits -= code_size;
|
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|
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// Interpret the code
|
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|
||||
if ((code > available) || (code == end_of_information))
|
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break;
|
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if (code == clear) {
|
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// Reset decoder.
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code_size = data_size + 1;
|
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code_mask = (1 << code_size) - 1;
|
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available = clear + 2;
|
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old_code = NullCode;
|
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continue;
|
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}
|
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if (old_code == NullCode) {
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pixelStack[top++] = suffix[code];
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old_code = code;
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first = code;
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continue;
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}
|
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in_code = code;
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if (code == available) {
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pixelStack[top++] = (byte) first;
|
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code = old_code;
|
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}
|
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while (code > clear) {
|
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pixelStack[top++] = suffix[code];
|
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code = prefix[code];
|
||||
}
|
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first = ((int) suffix[code]) & 0xff;
|
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|
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// Add a new string to the string table,
|
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|
||||
if (available >= MaxStackSize)
|
||||
break;
|
||||
pixelStack[top++] = (byte) first;
|
||||
prefix[available] = (short) old_code;
|
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suffix[available] = (byte) first;
|
||||
available++;
|
||||
if (((available & code_mask) == 0) && (available < MaxStackSize)) {
|
||||
code_size++;
|
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code_mask += available;
|
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}
|
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old_code = in_code;
|
||||
}
|
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|
||||
// Pop a pixel off the pixel stack.
|
||||
|
||||
top--;
|
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i++;
|
||||
|
||||
SetPixel(xpos, line, pixelStack[top]);
|
||||
++xpos;
|
||||
if (xpos >= iw) {
|
||||
xpos = 0;
|
||||
line += inc;
|
||||
if (line >= ih) {
|
||||
if (interlace) {
|
||||
do {
|
||||
pass++;
|
||||
switch (pass) {
|
||||
case 2:
|
||||
line = 4;
|
||||
break;
|
||||
case 3:
|
||||
line = 2;
|
||||
inc = 4;
|
||||
break;
|
||||
case 4:
|
||||
line = 1;
|
||||
inc = 2;
|
||||
break;
|
||||
default: // this shouldn't happen
|
||||
line = ih - 1;
|
||||
inc = 0;
|
||||
break;
|
||||
}
|
||||
} while (line >= ih);
|
||||
}
|
||||
else {
|
||||
line = ih - 1; // this shouldn't happen
|
||||
inc = 0;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
return skipZero;
|
||||
}
|
||||
|
||||
|
||||
protected void SetPixel(int x, int y, int v) {
|
||||
if (m_bpc == 8) {
|
||||
int pos = x + iw * y;
|
||||
m_out[pos] = (byte)v;
|
||||
}
|
||||
else {
|
||||
int pos = m_line_stride * y + x / (8 / m_bpc);
|
||||
int vout = v << (8 - m_bpc * (x % (8 / m_bpc))- m_bpc);
|
||||
m_out[pos] |= (byte)vout;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Resets frame state for reading next image.
|
||||
*/
|
||||
protected void ResetFrame() {
|
||||
}
|
||||
|
||||
/**
|
||||
* Reads Graphics Control Extension values
|
||||
*/
|
||||
protected void ReadGraphicControlExt() {
|
||||
inp.ReadByte(); // block size
|
||||
int packed = inp.ReadByte(); // packed fields
|
||||
dispose = (packed & 0x1c) >> 2; // disposal method
|
||||
if (dispose == 0)
|
||||
dispose = 1; // elect to keep old image if discretionary
|
||||
transparency = (packed & 1) != 0;
|
||||
delay = ReadShort() * 10; // delay inp milliseconds
|
||||
transIndex = inp.ReadByte(); // transparent color index
|
||||
inp.ReadByte(); // block terminator
|
||||
}
|
||||
|
||||
/**
|
||||
* Skips variable length blocks up to and including
|
||||
* next zero length block.
|
||||
*/
|
||||
protected void Skip() {
|
||||
do {
|
||||
ReadBlock();
|
||||
} while (blockSize > 0);
|
||||
}
|
||||
|
||||
private void ReadFully(byte[] b, int offset, int count) {
|
||||
while (count > 0) {
|
||||
int n = inp.Read(b, offset, count);
|
||||
if (n <= 0)
|
||||
throw new IOException("Insufficient data.");
|
||||
count -= n;
|
||||
offset += n;
|
||||
}
|
||||
}
|
||||
|
||||
internal class GifFrame {
|
||||
internal Image image;
|
||||
internal int ix;
|
||||
internal int iy;
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user