/* This file is part of dvi2bitmap; see README for copyrights and licence */
/*
* GIFEncode.cc - GIF image compression interface.
*
* This file is based on ppmtogif.c program which is part of the
* pbmplus distribution.
*
* The header at the top of ppmtogif.c is reproduced below.
*/
/* ppmtogif.c - read a portable pixmap and produce a GIF file
**
** Based on GIFENCOD by David Rowley <mgardi@watdscu.waterloo.edu>.A
** Lempel-Zim compression based on "compress".
**
** Modified by Marcel Wijkstra <wijkstra@fwi.uva.nl>
**
**
** Copyright (C) 1989 by Jef Poskanzer.
**
** 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 software is provided "as is" without express or
** implied warranty.
**
** The Graphics Interchange Format(c) is the Copyright property of
** CompuServe Incorporated. GIF(sm) is a Service Mark property of
** CompuServe Incorporated.
*/
#include <config.h>
// Minimally converted to a C++ class
#include "Bitmap.h" // for BitmapError exception class
#include "GIFBitmap.h"
#ifdef HAVE_CSTD_INCLUDE
#include <cmath>
#else
#include <math.h> // for floor() and ceil() in iround
#endif
using STD::fopen;
using STD::fwrite;
using STD::fputc;
using STD::fclose;
using STD::fflush;
using STD::fprintf;
using STD::floor;
using STD::ceil;
using STD::sqrt;
const unsigned long GIFBitmap::masks[]
= { 0x0000,
0x0001, 0x0003, 0x0007, 0x000F,
0x001F, 0x003F, 0x007F, 0x00FF,
0x01FF, 0x03FF, 0x07FF, 0x0FFF,
0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
GIFBitmap::GIFBitmap (const int w, const int h, const int bpp)
: BitmapImage (w, h, bpp),
Pass(0), maxbits(BITS), hsize(HSIZE), free_ent(0), clear_flg(0),
in_count(1), out_count(0), cur_accum(0), cur_bits(0)
{
maxmaxcode = (code_int)1 << BITS;
if (verbosity_ > normal)
fprintf (stderr, "GIFBitmap: w=%d h=%d\n", w, h);
}
GIFBitmap::~GIFBitmap()
{
}
inline int iround (float f)
{
return static_cast<int>(f>0 ? floor(f+0.5) : ceil(f-0.5));
}
void GIFBitmap::write (const string filename)
{
if (bitmapRows_ != h_)
throw DviBug ("attempt to GIFBitmap::write with incomplete bitmap");
// make a colour table, appropriate for bpp_ bits-per-pixel
if (bpp_ > 8)
throw DviBug ("max of 8 bits-per-pixel");
const int ncolours = 1<<bpp_;
int *RedCT = new int[ncolours];
int *GreenCT = new int[ncolours];
int *BlueCT = new int[ncolours];
int diffred = fg_.red -bg_.red;
int diffgreen = fg_.green-bg_.green;
int diffblue = fg_.blue -bg_.blue;
for (int i=0; i<ncolours; i++)
{
// Following is a rather `steeper' colour table than the
// obvious linear one, which should plausibly therefore be
// less prone to the `halo' you can get when transparent
// images are viewed against a substantially different
// background from the one they were intended for. Having
// said that, however, I can't see much difference when I
// examine them.
#if 1
double rat = sqrt(static_cast<double>(i)/(ncolours-1));
#else
float rat = static_cast<float>(i)/(ncolours-1);
#endif
RedCT[i] = bg_.red + iround(rat*diffred);
GreenCT[i] = bg_.green + iround(rat*diffgreen);
BlueCT[i] = bg_.blue + iround(rat*diffblue);
}
if (verbosity_ > normal)
{
fprintf (stderr, "GIFBitmap colour tables:\n");
for (int i=0; i<ncolours; i++)
fprintf (stderr, "%d\t%d\t%d\t%d\n",
i, RedCT[i], GreenCT[i], BlueCT[i]);
}
//const int step = 256 >> bpp_;
//int *CT = new int[ncolours];
//for (int i=0, val=255; i<ncolours-1; i++, val-=step)
//CT[i] = val;
//CT[ncolours-1] = 0;
FILE *F = fopen (filename.c_str(), "wb");
if (F == 0)
throw BitmapError ("can't open GIF file "+filename+" to write");
GIFEncode (F, // open file
w_, h_, // width and height of bitmap
1, // interlace?
0, // which CT entry is the background?
(isTransparent_ ? 0 : -1), // make entry 0 transparent, if req'd
bpp_, // bits-per-pixel
//CT, CT, CT // colour tables
RedCT, GreenCT, BlueCT
);
// GIFEncode closes the stream when it's finished
delete[] RedCT;
delete[] GreenCT;
delete[] BlueCT;
}
/*****************************************************************************
*
* GIFENCODE.C - GIF Image compression interface
*
* GIFEncode( FName, GHeight, GWidth, GInterlace, Background, Transparent,
* BitsPerPixel, Red, Green, Blue, GetPixel )
*
*****************************************************************************/
#define TRUE 1
#define FALSE 0
//static int Width, Height;
//static int curx, cury;
//static long CountDown;
//static int Pass = 0;
//static int Interlace;
/*
* Bump the 'curx' and 'cury' to point to the next pixel
*/
void GIFBitmap::BumpPixel(void)
{
/*
* Bump the current X position
*/
++curx;
/*
* If we are at the end of a scan line, set curx back to the beginning
* If we are interlaced, bump the cury to the appropriate spot,
* otherwise, just increment it.
*/
if( curx == Width ) {
curx = 0;
if( !Interlace )
++cury;
else {
switch( Pass ) {
case 0:
cury += 8;
if( cury >= Height ) {
++Pass;
cury = 4;
}
break;
case 1:
cury += 8;
if( cury >= Height ) {
++Pass;
cury = 2;
}
break;
case 2:
cury += 4;
if( cury >= Height ) {
++Pass;
cury = 1;
}
break;
case 3:
cury += 2;
break;
}
}
}
}
/*
* Return the next pixel from the image
*/
int GIFBitmap::GIFNextPixel(void)
{
int r;
if( CountDown == 0 )
return EOF;
--CountDown;
//r = ( * getpixel )( curx, cury );
r = static_cast<int>(bitmap_[cury*w_+curx]);
//fputc ((bitmap_[cury*w_+curx] ? '*' : '.'), stderr);
//if (curx == w_-1)
// fputc ('\n', stderr);
BumpPixel();
return r;
}
/* public */
void GIFBitmap::GIFEncode(FILE* fp,
int GWidth, int GHeight,
int GInterlace,
int Background,
int Transparent,
int BitsPerPixel,
int *Red, int *Green, int *Blue)
{
int B;
int RWidth, RHeight;
int LeftOfs, TopOfs;
int Resolution;
int ColorMapSize;
int InitCodeSize;
int i;
Interlace = GInterlace;
ColorMapSize = 1 << BitsPerPixel;
RWidth = Width = GWidth;
RHeight = Height = GHeight;
LeftOfs = TopOfs = 0;
Resolution = BitsPerPixel;
/*
* Calculate number of bits we are expecting
*/
CountDown = (long)Width * (long)Height;
/*
* Indicate which pass we are on (if interlace)
*/
Pass = 0;
/*
* The initial code size
*/
if( BitsPerPixel <= 1 )
InitCodeSize = 2;
else
InitCodeSize = BitsPerPixel;
/*
* Set up the current x and y position
*/
curx = cury = 0;
/*
* Write the Magic header
*/
fwrite( Transparent < 0 ? "GIF87a" : "GIF89a", 1, 6, fp );
/*
* Write out the screen width and height
*/
Putword( RWidth, fp );
Putword( RHeight, fp );
/*
* Indicate that there is a global colour map
*/
B = 0x80; /* Yes, there is a color map */
/*
* OR in the resolution
*/
B |= (Resolution - 1) << 5;
/*
* OR in the Bits per Pixel
*/
B |= (BitsPerPixel - 1);
/*
* Write it out
*/
fputc( B, fp );
/*
* Write out the Background colour
*/
fputc( Background, fp );
/*
* Byte of 0's (future expansion)
*/
fputc( 0, fp );
/*
* Write out the Global Colour Map
*/
for( i=0; i<ColorMapSize; ++i ) {
fputc( Red[i], fp );
fputc( Green[i], fp );
fputc( Blue[i], fp );
}
/*
* Write out extension for transparent colour index, if necessary.
*/
if ( Transparent >= 0 ) {
fputc( '!', fp );
fputc( 0xf9, fp );
fputc( 4, fp );
fputc( 1, fp );
fputc( 0, fp );
fputc( 0, fp );
fputc( Transparent, fp );
fputc( 0, fp );
}
/*
* Write an Image separator
*/
fputc( ',', fp );
/*
* Write the Image header
*/
Putword( LeftOfs, fp );
Putword( TopOfs, fp );
Putword( Width, fp );
Putword( Height, fp );
/*
* Write out whether or not the image is interlaced
*/
if( Interlace )
fputc( 0x40, fp );
else
fputc( 0x00, fp );
/*
* Write out the initial code size
*/
fputc( InitCodeSize, fp );
/*
* Go and actually compress the data
*/
compress( InitCodeSize+1, fp);
/*
* Write out a Zero-length packet (to end the series)
*/
fputc( 0, fp );
/*
* Write the GIF file terminator
*/
fputc( ';', fp );
/*
* And close the file
*/
fclose( fp );
}
/*
* Write out a word to the GIF file
*/
void GIFBitmap::Putword(int w, FILE* fp)
{
fputc( w & 0xff, fp );
fputc( (w / 256) & 0xff, fp );
}
/***************************************************************************
*
* GIFCOMPR.C - GIF Image compression routines
*
* Lempel-Ziv compression based on 'compress'. GIF modifications by
* David Rowley (mgardi@watdcsu.waterloo.edu)
*
***************************************************************************/
/*
* General DEFINEs
*/
// These #defines moved to class constants
//#define BITS 12
//#define HSIZE 5003 /* 80% occupancy */
#ifdef NO_UCHAR
typedef char char_type;
#else /*NO_UCHAR*/
typedef unsigned char char_type;
#endif /*NO_UCHAR*/
/*
*
* GIF Image compression - modified 'compress'
*
* Based on: compress.c - File compression ala IEEE Computer, June 1984.
*
* By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
* Jim McKie (decvax!mcvax!jim)
* Steve Davies (decvax!vax135!petsd!peora!srd)
* Ken Turkowski (decvax!decwrl!turtlevax!ken)
* James A. Woods (decvax!ihnp4!ames!jaw)
* Joe Orost (decvax!vax135!petsd!joe)
*
*/
#include <ctype.h>
#define ARGVAL() (*++(*argv) || (--argc && *++argv))
//static int n_bits; /* number of bits/code */
//static int maxbits = BITS; /* user settable max # bits/code */
//static code_int maxcode; /* maximum code, given n_bits */
//static code_int maxmaxcode = (code_int)1 << BITS; /* should NEVER generate this code */
#ifdef COMPATIBLE /* But wrong! */
# define MAXCODE(n_bits) ((code_int) 1 << (n_bits) - 1)
#else /*COMPATIBLE*/
# define MAXCODE(n_bits) (((code_int) 1 << (n_bits)) - 1)
#endif /*COMPATIBLE*/
//static count_int htab [HSIZE];
//static unsigned short codetab [HSIZE];
#define HashTabOf(i) htab[i]
#define CodeTabOf(i) codetab[i]
//static code_int hsize = HSIZE; /* for dynamic table sizing */
/*
* To save much memory, we overlay the table used by compress() with those
* used by decompress(). The tab_prefix table is the same size and type
* as the codetab. The tab_suffix table needs 2**BITS characters. We
* get this from the beginning of htab. The output stack uses the rest
* of htab, and contains characters. There is plenty of room for any
* possible stack (stack used to be 8000 characters).
*/
#define tab_prefixof(i) CodeTabOf(i)
#define tab_suffixof(i) ((char_type*)(htab))[i]
#define de_stack ((char_type*)&tab_suffixof((code_int)1<<BITS))
//static code_int free_ent = 0; /* first unused entry */
/*
* block compression parameters -- after all codes are used up,
* and compression rate changes, start over.
*/
//static int clear_flg = 0;
//static int offset;
//static long int in_count = 1; /* length of input */
//static long int out_count = 0; /* # of codes output (for debugging) */
/*
* compress stdin to stdout
*
* Algorithm: use open addressing double hashing (no chaining) on the
* prefix code / next character combination. We do a variant of Knuth's
* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
* secondary probe. Here, the modular division first probe is gives way
* to a faster exclusive-or manipulation. Also do block compression with
* an adaptive reset, whereby the code table is cleared when the compression
* ratio decreases, but after the table fills. The variable-length output
* codes are re-sized at this point, and a special CLEAR code is generated
* for the decompressor. Late addition: construct the table according to
* file size for noticeable speed improvement on small files. Please direct
* questions about this implementation to ames!jaw.
*/
//static int g_init_bits;
//static FILE* g_outfile;
//static int ClearCode;
//static int EOFCode;
void GIFBitmap::compress(int init_bits, FILE* outfile)
{
register long fcode;
register code_int i /* = 0 */;
register int c;
register code_int ent;
register code_int disp;
register code_int hsize_reg;
register int hshift;
/*
* Set up the globals: g_init_bits - initial number of bits
* g_outfile - pointer to output file
*/
g_init_bits = init_bits;
g_outfile = outfile;
/*
* Set up the necessary values
*/
offset = 0;
out_count = 0;
clear_flg = 0;
in_count = 1;
maxcode = MAXCODE(n_bits = g_init_bits);
ClearCode = (1 << (init_bits - 1));
EOFCode = ClearCode + 1;
free_ent = ClearCode + 2;
char_init();
ent = GIFNextPixel();
hshift = 0;
for ( fcode = (long) hsize; fcode < 65536L; fcode *= 2L )
++hshift;
hshift = 8 - hshift; /* set hash code range bound */
hsize_reg = hsize;
cl_hash( (count_int) hsize_reg); /* clear hash table */
output( (code_int)ClearCode );
#ifdef SIGNED_COMPARE_SLOW
while ( (c = GIFNextPixel()) != (unsigned) EOF ) {
#else /*SIGNED_COMPARE_SLOW*/
while ( (c = GIFNextPixel()) != EOF ) { /* } */
#endif /*SIGNED_COMPARE_SLOW*/
++in_count;
fcode = (long) (((long) c << maxbits) + ent);
i = (((code_int)c << hshift) ^ ent); /* xor hashing */
if ( HashTabOf (i) == fcode ) {
ent = CodeTabOf (i);
continue;
} else if ( (long)HashTabOf (i) < 0 ) /* empty slot */
goto nomatch;
disp = hsize_reg - i; /* secondary hash (after G. Knott) */
if ( i == 0 )
disp = 1;
probe:
if ( (i -= disp) < 0 )
i += hsize_reg;
if ( HashTabOf (i) == fcode ) {
ent = CodeTabOf (i);
continue;
}
if ( (long)HashTabOf (i) > 0 )
goto probe;
nomatch:
output ( (code_int) ent );
++out_count;
ent = c;
#ifdef SIGNED_COMPARE_SLOW
if ( (unsigned) free_ent < (unsigned) maxmaxcode) {
#else /*SIGNED_COMPARE_SLOW*/
if ( free_ent < maxmaxcode ) { /* } */
#endif /*SIGNED_COMPARE_SLOW*/
CodeTabOf (i) = (short)free_ent++; /* code -> hashtable */
HashTabOf (i) = fcode;
} else
cl_block();
}
/*
* Put out the final code.
*/
output( (code_int)ent );
++out_count;
output( (code_int) EOFCode );
}
/*****************************************************************
* TAG( output )
*
* Output the given code.
* Inputs:
* code: A n_bits-bit integer. If == -1, then EOF. This assumes
* that n_bits =< (long)wordsize - 1.
* Outputs:
* Outputs code to the file.
* Assumptions:
* Chars are 8 bits long.
* Algorithm:
* Maintain a BITS character long buffer (so that 8 codes will
* fit in it exactly). Use the VAX insv instruction to insert each
* code in turn. When the buffer fills up empty it and start over.
*/
//static unsigned long cur_accum = 0;
//static int cur_bits = 0;
//static unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
// 0x001F, 0x003F, 0x007F, 0x00FF,
// 0x01FF, 0x03FF, 0x07FF, 0x0FFF,
// 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
void GIFBitmap::output(code_int code)
{
cur_accum &= masks[ cur_bits ];
if( cur_bits > 0 )
cur_accum |= ((long)code << cur_bits);
else
cur_accum = code;
cur_bits += n_bits;
while( cur_bits >= 8 ) {
char_out( (unsigned int)(cur_accum & 0xff) );
cur_accum >>= 8;
cur_bits -= 8;
}
/*
* If the next entry is going to be too big for the code size,
* then increase it, if possible.
*/
if ( free_ent > maxcode || clear_flg ) {
if( clear_flg ) {
maxcode = MAXCODE (n_bits = g_init_bits);
clear_flg = 0;
} else {
++n_bits;
if ( n_bits == maxbits )
maxcode = maxmaxcode;
else
maxcode = MAXCODE(n_bits);
}
}
if( code == EOFCode ) {
/*
* At EOF, write the rest of the buffer.
*/
while( cur_bits > 0 ) {
char_out( (unsigned int)(cur_accum & 0xff) );
cur_accum >>= 8;
cur_bits -= 8;
}
flush_char();
fflush( g_outfile );
if( ferror( g_outfile ) )
throw BitmapError ("error in GIFBitmap");
}
}
/*
* Clear out the hash table
*/
void GIFBitmap::cl_block () /* table clear for block compress */
{
cl_hash ( (count_int) hsize );
free_ent = ClearCode + 2;
clear_flg = 1;
output( (code_int)ClearCode );
}
void GIFBitmap::cl_hash(count_int p_hsize) /* reset code table */
/*register count_int hsize;*/
{
register count_int *htab_p = htab+p_hsize;
register long i;
register long m1 = -1;
i = p_hsize - 16;
do { /* might use Sys V memset(3) here */
*(htab_p-16) = m1;
*(htab_p-15) = m1;
*(htab_p-14) = m1;
*(htab_p-13) = m1;
*(htab_p-12) = m1;
*(htab_p-11) = m1;
*(htab_p-10) = m1;
*(htab_p-9) = m1;
*(htab_p-8) = m1;
*(htab_p-7) = m1;
*(htab_p-6) = m1;
*(htab_p-5) = m1;
*(htab_p-4) = m1;
*(htab_p-3) = m1;
*(htab_p-2) = m1;
*(htab_p-1) = m1;
htab_p -= 16;
} while ((i -= 16) >= 0);
for ( i += 16; i > 0; --i )
*--htab_p = m1;
}
/*
static void
writeerr()
{
pm_error( "error writing output file" );
}
*/
/******************************************************************************
*
* GIF Specific routines
*
******************************************************************************/
/*
* Number of characters so far in this 'packet'
*/
//static int a_count;
/*
* Set up the 'byte output' routine
*/
void GIFBitmap::char_init()
{
a_count = 0;
}
/*
* Define the storage for the packet accumulator
*/
//static char accum[ 256 ];
/*
* Add a character to the end of the current packet, and if it is 254
* characters, flush the packet to disk.
*/
void GIFBitmap::char_out( int c )
{
accum[ a_count++ ] = (char)c;
if( a_count >= 254 )
flush_char();
}
/*
* Flush the packet to disk, and reset the accumulator
*/
void GIFBitmap::flush_char()
{
if( a_count > 0 ) {
fputc( a_count, g_outfile );
fwrite( accum, 1, a_count, g_outfile );
a_count = 0;
}
}
/* The End */