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fltk/fluid/gif.cxx

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//
// "$Id: gif.cxx,v 1.3.2.5 2001/01/22 15:13:39 easysw Exp $"
//
// GIF support for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2001 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems to "fltk-bugs@fltk.org".
//
// Read a .gif file and convert it to a "xpm" format (actually my
// modified one with compressed colormaps).
// 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.
*
* This file is provided AS IS with no warranties of any kind. The author
* shall have no liability with respect to the infringement of copyrights,
* trade secrets or any patents by this file or any part thereof. In no
* event will the author be liable for any lost revenue or profits or
* other special, indirect and consequential damages.
*
* Comments and additions should be sent to the author:
*
* Patrick J. Naughton
* Sun Microsystems, Inc.
* 2550 Garcia Ave, MS 14-40
* Mountain View, CA 94043
* (415) 336-1080
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef unsigned char uchar;
#define NEXTBYTE getc(GifFile)
#define GETSHORT(var) var = NEXTBYTE; var += NEXTBYTE << 8
int gif2xpm(
const char *infname,// filename for error messages
FILE *GifFile, // file to read
char*** datap, // return xpm data here
int** lengthp, // return line lengths here
int inumber // which image in movie (0 = first)
) {
{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') {
fprintf(stderr,"%s is not a GIF file.\n", infname); return 0;}
if (b[3]!='8' || b[4]>'9' || b[5]!= 'a')
fprintf(stderr,"%s is version %c%c%c.\n",infname,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 (int i=0; i < ColorMapSize; i++) {
Red[i] = NEXTBYTE;
Green[i] = NEXTBYTE;
Blue[i] = NEXTBYTE;
}
} else {
fprintf(stderr,"%s does not have a colormap.\n", infname);
for (int 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 (;;) {
int i = NEXTBYTE;
if (i<0) {fprintf(stderr,"%s: unexpected EOF\n",infname); 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 if (ch == 0xFE) { //Gif Comment
#if 0
if(blocklen>0) {
char *comment=new char[blocklen+1];
int l;
for(l=0;blocklen;l++,blocklen--)
comment[l]=NEXTBYTE;
comment[l]=0;
fprintf(stderr,"%s: Gif Comment: '%s'\n", infname, comment);
delete comment;
NEXTBYTE; //End marker
}
#endif
} else {
fprintf(stderr,"%s: unknown gif extension 0x%02x\n", infname, 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 {
fprintf(stderr,"%s: unknown gif code 0x%02x\n", infname, i);
blocklen = 0;
}
// skip the data:
while (blocklen>0) {while (blocklen--) {NEXTBYTE;} blocklen=NEXTBYTE;}
}
uchar *Image = new uchar[Width*Height];
if (!Image) {
fprintf (stderr, "Insufficient memory\n");
exit (2);
}
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<<CodeSize) - 1;
int FreeCode = FirstFree;
int OldCode = ClearCode;
// tables used by LZW decompresser:
short int Prefix[4096];
uchar Suffix[4096];
int blocklen = NEXTBYTE;
uchar thisbyte = NEXTBYTE; blocklen--;
int frombit = 0;
for (;;) {
/* Fetch the next code from the raster data stream. The codes can be
* any length from 3 to 12 bits, packed into 8-bit bytes, so we have to
* maintain our location as a pointer and a bit offset.
* In addition, gif adds totally useless and annoying block counts
* that must be correctly skipped over. */
int CurCode = thisbyte;
if (frombit+CodeSize > 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<<CodeSize) - 1;
FreeCode = FirstFree;
OldCode = ClearCode;
continue;
}
if (CurCode == EOFCode) break;
uchar OutCode[1025]; // temporary array for reversing codes
uchar *tp = OutCode;
int i;
if (CurCode < FreeCode) i = CurCode;
else if (CurCode == FreeCode) {*tp++ = FinChar; i = OldCode;}
else {fprintf(stderr,"%s : LZW Barf!\n",infname); break;}
while (i >= 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:
// allocate line pointer arrays:
char** data = new char*[Height+3];
*datap = data;
int* length = new int[Height+2];
*lengthp = length;
// 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;
}
// find out what colors are actually used:
uchar used[256]; uchar remap[256];
int i;
for (i = 0; i < ColorMapSize; i++) used[i] = 0;
p = Image+Width*Height;
while (p-- > Image) used[*p] = 1;
// remap them to start with printing characters:
int base = has_transparent && used[0] ? ' ' : ' '+1;
int numcolors = 0;
for (i = 0; i < ColorMapSize; i++) if (used[i]) {
remap[i] = base++;
numcolors++;
}
// write the first line of xpm data (use suffix as temp array):
length[0] = sprintf((char*)(Suffix),
"%d %d %d %d",Width,Height,-numcolors,1);
data[0] = new char[length[0]+1];
strcpy(data[0], (char*)Suffix);
// write the colormap
length[1] = 4*numcolors;
data[1] = (char*)(p = new uchar[4*numcolors]);
for (i = 0; i < ColorMapSize; i++) if (used[i]) {
*p++ = remap[i];
*p++ = Red[i];
*p++ = Green[i];
*p++ = Blue[i];
}
// remap the image data:
p = Image+Width*Height;
while (p-- > Image) *p = remap[*p];
// split the image data into lines:
for (i=0; i<Height; i++) {
data[i+2] = (char*)(Image + i*Width);
length[i+2] = Width;
}
data[Height+2] = 0; // null to end string array
return Height+2;
}
//
// End of "$Id: gif.cxx,v 1.3.2.5 2001/01/22 15:13:39 easysw Exp $".
//
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