/* * $Id: readgif.cxx,v 4.1 2004/05/25 06:40:20 hut66au Exp $ * * Imview, the portable image analysis application * http://www.cmis.csiro.au/Hugues.Talbot/imview * ---------------------------------------------------------- * * Imview is an attempt to provide an image display application * suitable for professional image analysis. It was started in * 1997 and is mostly the result of the efforts of Hugues Talbot, * Image Analysis Project, CSIRO Mathematical and Information * Sciences, with help from others (see the CREDITS files for * more information) * * Imview is Copyrighted (C) 1997-2001 by Hugues Talbot and was * supported in parts by the Australian Commonwealth Science and * Industry Research Organisation. Please see the COPYRIGHT file * for full details. Imview also includes the contributions of * many others. Please see the CREDITS file for full details. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. * */ // readgif.C // adapted for my own purposed by Hugues Talbot 21 Jan 1998 // in particular got rid of the silly conversion to pixmap! // now returns the data in a simple GL or RGB buffer // Extensively modified from original code for gif2ras by // Patrick J. Naughton of Sun Microsystems. The original // copyright notice follows: /* gif2ras.c - Converts from a Compuserve GIF (tm) image to a Sun Raster image. * * Copyright (c) 1988 by Patrick J. Naughton * * Author: Patrick J. Naughton * naughton@wind.sun.com * * Permission to use, copy, modify, and distribute this software and its * documentation for any purpose and without fee is hereby granted, * provided that the above copyright notice appear in all copies and that * both that copyright notice and this permission notice appear in * supporting documentation. * */ #include "imnmspc.hxx" // name space definition if needed #include #include #include #include "imview.hxx" #include "imSystem.hxx" #include "imageIO.hxx" #include "readgif.hxx" extern imageIO *IOBlackBox; // DEC cxx doesn't like that! static uchar *loadGifImage(FILE *GifFile, int *imWidth,int *imHeight, int *imDepth, int inumber=0); int readGifImage(const char *GifFileName, // file to read int inumber) // which image in movie (0 = first) { FILE *fp; uchar *outbuf; int imWidth, imHeight, imDepth; if ((fp = im_fopen(GifFileName, "rb")) == 0) { errprintf("Cannot open %s\n", GifFileName); return 0; } outbuf = loadGifImage(fp, &imWidth, &imHeight, &imDepth, inumber); // this will require no translation IOBlackBox->setImData(outbuf); IOBlackBox->setCurrImgWidth(imWidth); IOBlackBox->setCurrImgHeight(imHeight); IOBlackBox->setCurrImgThickness(1); IOBlackBox->setXOffset(0); IOBlackBox->setYOffset(0); IOBlackBox->setZOffset(0); IOBlackBox->setCurrImgNbComps(1); // only a single image in a GIF file IOBlackBox->setCurrImgNbSamples(imDepth); IOBlackBox->setCurrImgSpp(imDepth); // needed here because no currBuffp IOBlackBox->setCurrPixType(IM_UINT1); IOBlackBox->setCurrImgType((imDepth == 3) ? IM_RGB : IM_SPECTRUM); IOBlackBox->setImgDesc("GIF"); fclose(fp); return (outbuf == 0); } #define NEXTBYTE getc(GifFile) #define GETSHORT(var) var = NEXTBYTE; var += NEXTBYTE << 8 // This function returns the number of frames // in an animated GIF file. Negative numbers indicate // errors int gifnbsubfiles(const char *fname) { int i; FILE *GifFile; int inumber = 0; if ((GifFile = im_fopen(fname, "rb")) == NULL) return -1; // can't read the file { char b[6]; if (fread(b,1,6,GifFile)<6) return 0; /* quit on eof */ if (b[0]!='G' || b[1]!='I' || b[2] != 'F') { dbgprintf("not a GIF file!\n"); return 0;} if (b[3]!='8' || b[4]>'9' || b[5]!= 'a') dbgprintf("GIF version %c%c%c. May cause trouble\n",b[3],b[4],b[5]); } int Width; GETSHORT(Width); int Height; GETSHORT(Height); uchar ch = NEXTBYTE; char HasColormap = ((ch & 0x80) != 0); int BitsPerPixel = (ch & 7) + 1; int ColorMapSize = 1 << BitsPerPixel; // int OriginalResolution = ((ch>>4)&7)+1; // int SortedTable = (ch&8)!=0; NEXTBYTE; // Background Color index NEXTBYTE; // Aspect ratio is N/64 // Read in global colormap: uchar transparent_pixel = 0; char has_transparent = 0; if (HasColormap) { for (i=0; i < ColorMapSize; i++) { NEXTBYTE; NEXTBYTE; NEXTBYTE; } } else { dbgprintf("File does not have a colormap.\n"); } int CodeSize; /* Code size, init from GIF header, increases... */ char Interlace; for (;;) { i = NEXTBYTE; if (i<0) {dbgprintf("reached EOF\n"); break;} int blocklen; if (i == 0x21) { // a "gif extension" ch = NEXTBYTE; blocklen = NEXTBYTE; if (ch==0xF9 && blocklen==4) { // Netscape animation extension char bits; bits = NEXTBYTE; NEXTBYTE; NEXTBYTE; // GETSHORT(delay); transparent_pixel = NEXTBYTE; if (bits & 1) has_transparent = 1; blocklen = NEXTBYTE; } else if (ch == 0xFF) { ; // Netscape repeat count } else { dbgprintf("unknown gif extension 0x%02x\n", ch); } } else if (i == 0x2c) { // an image NEXTBYTE; NEXTBYTE; // GETSHORT(x_position); NEXTBYTE; NEXTBYTE; // GETSHORT(y_position); GETSHORT(Width); GETSHORT(Height); ch = NEXTBYTE; Interlace = ((ch & 0x40) != 0); if (ch&0x80) { // skip over local color map int n = 1<<((ch&7)+1); // does this replace ColorMapSize ?? for (i=0; i < n; i++) { NEXTBYTE; NEXTBYTE; NEXTBYTE; } } CodeSize = NEXTBYTE+1; inumber++; // count the next block blocklen = NEXTBYTE; } else { dbgprintf("unknown gif code 0x%02x, piking out.\n", i); blocklen = 0; break; // taking no chance there. } // skip the data: while (blocklen>0) {while (blocklen--) {NEXTBYTE;} blocklen=NEXTBYTE;} } fclose(GifFile); return inumber; } static uchar *loadGifImage(FILE *GifFile, // file to read int *imWidth, int *imHeight, int *imDepth, int inumber // which image in movie (0 = first) ) { uchar *outbuf = 0; int i; { char b[6]; if (fread(b,1,6,GifFile)<6) return 0; /* quit on eof */ if (b[0]!='G' || b[1]!='I' || b[2] != 'F') { dbgprintf("not a GIF file!\n"); return 0;} if (b[3]!='8' || b[4]>'9' || b[5]!= 'a') dbgprintf("GIF version %c%c%c. May cause trouble\n",b[3],b[4],b[5]); } int Width; GETSHORT(Width); int Height; GETSHORT(Height); uchar ch = NEXTBYTE; char HasColormap = ((ch & 0x80) != 0); int BitsPerPixel = (ch & 7) + 1; int ColorMapSize = 1 << BitsPerPixel; // int OriginalResolution = ((ch>>4)&7)+1; // int SortedTable = (ch&8)!=0; NEXTBYTE; // Background Color index NEXTBYTE; // Aspect ratio is N/64 // Read in global colormap: uchar transparent_pixel = 0; char has_transparent = 0; uchar Red[256], Green[256], Blue[256]; /* color map */ if (HasColormap) { for (i=0; i < ColorMapSize; i++) { Red[i] = NEXTBYTE; Green[i] = NEXTBYTE; Blue[i] = NEXTBYTE; } } else { dbgprintf("File does not have a colormap.\n"); for (i = 0; i < ColorMapSize; i++) Red[i] = Green[i] = Blue[i] = (i*256+ColorMapSize-1)/ColorMapSize; } int CodeSize; /* Code size, init from GIF header, increases... */ char Interlace; for (;;) { i = NEXTBYTE; if (i<0) {dbgprintf("unexpected EOF\n"); return 0;} int blocklen; // if (i == 0x3B) return 0; eof code if (i == 0x21) { // a "gif extension" ch = NEXTBYTE; blocklen = NEXTBYTE; if (ch==0xF9 && blocklen==4) { // Netscape animation extension char bits; bits = NEXTBYTE; NEXTBYTE; NEXTBYTE; // GETSHORT(delay); transparent_pixel = NEXTBYTE; if (bits & 1) has_transparent = 1; blocklen = NEXTBYTE; } else if (ch == 0xFF) { ; // Netscape repeat count } else { dbgprintf("unknown gif extension 0x%02x\n", ch); } } else if (i == 0x2c) { // an image NEXTBYTE; NEXTBYTE; // GETSHORT(x_position); NEXTBYTE; NEXTBYTE; // GETSHORT(y_position); GETSHORT(Width); GETSHORT(Height); ch = NEXTBYTE; Interlace = ((ch & 0x40) != 0); if (ch&0x80) { // read local color map int n = 1<<((ch&7)+1); // does this replace ColorMapSize ?? for (i=0; i < n; i++) { Red[i] = NEXTBYTE; Green[i] = NEXTBYTE; Blue[i] = NEXTBYTE; } } CodeSize = NEXTBYTE+1; if (!inumber--) break; // okay, this is the image we want blocklen = NEXTBYTE; } else { dbgprintf("unknown gif code 0x%02x\n", i); blocklen = 0; } // skip the data: while (blocklen>0) {while (blocklen--) {NEXTBYTE;} blocklen=NEXTBYTE;} } uchar *Image = new uchar[Width*Height]; if (!Image) { errprintf("Insufficient memory\n"); return(outbuf); } int YC = 0, Pass = 0; /* Used to de-interlace the picture */ uchar *p = Image; uchar *eol = p+Width; int InitCodeSize = CodeSize; int ClearCode = (1 << (CodeSize-1)); int EOFCode = ClearCode + 1; int FirstFree = ClearCode + 2; int FinChar = 0; int ReadMask = (1< 7) { if (blocklen <= 0) { blocklen = NEXTBYTE; if (blocklen <= 0) break; } thisbyte = NEXTBYTE; blocklen--; CurCode |= thisbyte<<8; } if (frombit+CodeSize > 15) { if (blocklen <= 0) { blocklen = NEXTBYTE; if (blocklen <= 0) break; } thisbyte = NEXTBYTE; blocklen--; CurCode |= thisbyte<<16; } CurCode = (CurCode>>frombit)&ReadMask; frombit = (frombit+CodeSize)%8; if (CurCode == ClearCode) { CodeSize = InitCodeSize; ReadMask = (1<= ColorMapSize) {*tp++ = Suffix[i]; i = Prefix[i];} *tp++ = FinChar = i; while (tp > OutCode) { *p++ = *--tp; if (p >= eol) { if (!Interlace) YC++; else switch (Pass) { case 0: YC += 8; if (YC >= Height) {Pass++; YC = 4;} break; case 1: YC += 8; if (YC >= Height) {Pass++; YC = 2;} break; case 2: YC += 4; if (YC >= Height) {Pass++; YC = 1;} break; case 3: YC += 2; break; } if (YC>=Height) YC=0; /* cheap bug fix when excess data */ p = Image + YC*Width; eol = p+Width; } } if (OldCode != ClearCode) { Prefix[FreeCode] = OldCode; Suffix[FreeCode] = FinChar; FreeCode++; if (FreeCode > ReadMask) { if (CodeSize < 12) { CodeSize++; ReadMask = (1 << CodeSize) - 1; } else FreeCode--; } } OldCode = CurCode; } // We are done reading the file, now convert to xpm: // transparent pixel must be zero, swap if it isn't: if (has_transparent && transparent_pixel != 0) { // swap transparent pixel with zero p = Image+Width*Height; while (p-- > Image) { if (*p==transparent_pixel) *p = 0; else if (!*p) *p = transparent_pixel; } uchar t; t = Red[0]; Red[0] = Red[transparent_pixel]; Red[transparent_pixel] = t; t =Green[0];Green[0]=Green[transparent_pixel];Green[transparent_pixel]=t; t =Blue[0];Blue[0] =Blue[transparent_pixel];Blue[transparent_pixel] = t; } // is the image colour or Grey-level? *imDepth = 1; for (i = 0 ; i < ColorMapSize ; i++) { if ((Red[i] != Green[i]) || (Red[i] != Blue[i])) { *imDepth = 3; break; } } *imWidth = Width; *imHeight = Height; int nbBytes = (*imWidth)*(*imHeight)*(*imDepth); outbuf = new uchar[nbBytes]; if (outbuf != 0) { uchar *end; uchar *q = Image; p = outbuf; end = p + nbBytes; // interprets the colour LUT if (*imDepth == 1) { while (p != end) { *p++ = Red[*q++]; } } else { while (p != end) { *p++ = Red[*q]; *p++ = Green[*q]; *p++ = Blue[*q++]; } } } delete[] Image; return outbuf; }