src/px/ra_gif.c

#ifndef lint
static const char       RCSid[] = "$Id: ra_gif.c,v 2.12 2011/05/20 02:06:39 greg Exp $";
#endif
/*
 * Convert from Radiance picture file to Compuserve GIF.
 * Currently, we don't know how to get back.
 */

#include  <math.h>

#include  "rtio.h"
#include  "platform.h"
#include  "color.h"
#include  "resolu.h"
#include  "clrtab.h"

#define MAXCOLORS               256

int rmap[MAXCOLORS];
int gmap[MAXCOLORS];
int bmap[MAXCOLORS];

int currow;
long  picstart;
uby8  clrtab[256][3];

extern int  samplefac;


COLR    *scanln;
uby8    *pixscan;

int  xmax, ymax;                        /* picture size */
double  gamv = 2.2;                     /* gamma correction */
int  greyscale = 0;                     /* convert to B&W? */
int  dither = 1;                        /* dither colors? */
int  bradj = 0;                         /* brightness adjustment */
int  ncolors = 0;                       /* number of colors requested */

char  *progname;

typedef int ifun_t(int x, int y); /* required by the GIF code below */

static void getrow(int  y);
static void mkclrmap(int        nc);
static void mkgrymap(int        nc);
static ifun_t getgifpix;

static void GIFEncode(FILE *fp, int GWidth, int GHeight, int GInterlace,
                int Background, int BitsPerPixel, int Red[], int Green[], int Blue[],
                ifun_t* GetPixel);


int
main(int  argc, char  *argv[])
{
        int  bitsperpix;
        int  i;
        SET_DEFAULT_BINARY();
        SET_FILE_BINARY(stdin);
        SET_FILE_BINARY(stdout);
        progname = argv[0];
        samplefac = 0;

        for (i = 1; i < argc; i++)
                if (argv[i][0] == '-')
                        switch (argv[i][1]) {
                        case 'g':
                                gamv = atof(argv[++i]);
                                break;
                        case 'b':
                                greyscale = 1;
                                break;
                        case 'd':
                                dither = !dither;
                                break;
                        case 'c':
                                ncolors = atoi(argv[++i]);
                                break;
                        case 'e':
                                if (argv[i+1][0] != '+' && argv[i+1][0] != '-')
                                        goto userr;
                                bradj = atoi(argv[++i]);
                                break;
                        case 'n':
                                samplefac = atoi(argv[++i]);
                                break;
                        default:
                                goto userr;
                        }
                else
                        break;

        if (i < argc-2)
                goto userr;
        if (i <= argc-1 && freopen(argv[i], "r", stdin) == NULL) {
                fprintf(stderr, "%s: cannot open input \"%s\"\n",
                                progname, argv[i]);
                exit(1);
        }
        if (i == argc-2 && freopen(argv[i+1], "w", stdout) == NULL) {
                fprintf(stderr, "%s: cannot open output \"%s\"\n",
                                progname, argv[i+1]);
                exit(1);
        }
        if (checkheader(stdin, COLRFMT, NULL) < 0 ||
                        fgetresolu(&xmax, &ymax, stdin) < 0) {
                fprintf(stderr, "%s: bad picture format\n", progname);
                exit(1);
        }
        picstart = ftell(stdin);
        currow = -1;
        scanln = (COLR *)malloc(xmax*sizeof(COLR));
        if (scanln == NULL) {
                fprintf(stderr, "%s: out of memory\n", progname);
                exit(1);
        }
                                /* set up gamma correction */
        setcolrgam(gamv);
                                /* figure out the bits per pixel */
        if ((ncolors < 2) | (ncolors > MAXCOLORS))
                ncolors = MAXCOLORS;
        for (bitsperpix = 1; ncolors > 1<<bitsperpix; bitsperpix++)
                ;
                                /* compute color map */
        if (greyscale)
                mkgrymap(ncolors);
        else
                mkclrmap(ncolors);
                                /* convert image */
        GIFEncode(stdout, xmax, ymax, 0, 0, bitsperpix,
                        rmap, gmap, bmap, getgifpix);
        exit(0);
userr:
        fprintf(stderr,
        "Usage: %s [-b][-d][-n samp][-c ncolors][-g gamv][-e +/-stops] input [output]\n",
                        progname);
        exit(1);
}


static void
getrow(                 /* get the specified row from our image */
        int  y
)
{
        if (y == currow)
                return;
        if (y < currow) {
                fseek(stdin, picstart, 0);
                currow = -1;
        }
        do
                if (freadcolrs(scanln, xmax, stdin) < 0) {
                        fprintf(stderr, "%s: error reading picture (y==%d)\n",
                                        progname, ymax-1-y);
                        exit(1);
                }
        while (++currow < y);
        if (bradj)
                shiftcolrs(scanln, xmax, bradj);
        colrs_gambs(scanln, xmax);
        if (pixscan != NULL) {
                if (samplefac)
                        neu_dith_colrs(pixscan, scanln, xmax);
                else
                        dith_colrs(pixscan, scanln, xmax);
        }
}


static void
mkclrmap(                       /* make our color map */
        int     nc
)
{
        register int    i;

        if ((samplefac ? neu_init(xmax*ymax) : new_histo(xmax*ymax)) == -1)
                goto memerr;
        for (i = 0; i < ymax; i++) {
                getrow(i);
                if (samplefac)
                        neu_colrs(scanln, xmax);
                else
                        cnt_colrs(scanln, xmax);
        }
        if (samplefac)
                neu_clrtab(nc);
        else
                new_clrtab(nc);
        for (i = 0; i < nc; i++) {
                rmap[i] = clrtab[i][RED];
                gmap[i] = clrtab[i][GRN];
                bmap[i] = clrtab[i][BLU];
        }
        if (dither && (pixscan = (uby8 *)malloc(xmax)) == NULL)
                goto memerr;
        return;
memerr:
        fprintf(stderr, "%s: out of memory\n", progname);
        exit(1);
}


static void
mkgrymap(
        int     nc
)
{
        register int    i;

        for (i = 0; i < nc; i++) {
                rmap[i] =
                gmap[i] =
                bmap[i] = ((unsigned)i<<8)/nc;
        }
}


static int
getgifpix(                      /* get a single pixel from our picture */
        int  x,
        int  y
)
{
        getrow(y);
        if (greyscale)
                return((normbright(scanln[x])*ncolors)>>8);
        if (pixscan != NULL)
                return(pixscan[x]);
        return(samplefac ? neu_map_pixel(scanln[x]) : map_pixel(scanln[x]));
}


/*
 * SCARY GIF code follows . . . . sorry.
 *
 * Based on GIFENCOD by David Rowley <[email protected]>.A
 * Lempel-Ziv compression based on "compress".
 *
 */

/*****************************************************************************
 *
 * GIFENCODE.C    - GIF Image compression interface
 *
 * GIFEncode( FName, GHeight, GWidth, GInterlace, Background,
 *            BitsPerPixel, Red, Green, Blue, GetPixel )
 *
 *****************************************************************************/

#define TRUE 1
#define FALSE 0

int Width, Height;
int curx, cury;
long CountDown;
int Pass;
int Interlace;
unsigned long cur_accum = 0;
int cur_bits = 0;

static void BumpPixel(void);
static int GIFNextPixel(ifun_t* getpixel);
static void Putword(int w, FILE *fp);
static void compress(int init_bits, FILE *outfile, ifun_t* ReadValue);


/* a code_int must be able to hold 2**CBITS values of type int, and also -1 */
typedef int             code_int;
typedef long int        count_int;
typedef unsigned char   char_type;

static void output(code_int  code);
static void cl_block(void);
static void cl_hash(count_int hsize);
static void writeerr(void);

static void char_init(void);
static void char_out(int c);
static void flush_char(void);
static void gammawarp(short *sbuf, float gam, int n);


/*
 * Bump the 'curx' and 'cury' to point to the next pixel
 */
static void
BumpPixel(void)
{
    curx++;
    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
 */
static int
GIFNextPixel(
        ifun_t* getpixel
)
{
    int r;

    if( CountDown == 0 )
        return EOF;
    CountDown--;
    r = (*getpixel)( curx, cury );
    BumpPixel();
    return r;
}

/*
 * public GIFEncode
 */
static void
GIFEncode(
        FILE *fp,
        int GWidth,
        int GHeight,
        int GInterlace,
        int Background,
        int BitsPerPixel,
        int Red[],
        int Green[],
        int Blue[],
        ifun_t* GetPixel
)
{
    int B;
    int RWidth, RHeight;
    int LeftOfs, TopOfs;
    int Resolution;
    int ColorMapSize;
    int InitCodeSize;
    int i;

    cur_accum = 0; /* globals */
    cur_bits = 0;

    Interlace = GInterlace;
    ColorMapSize = 1 << BitsPerPixel;
    RWidth = Width = GWidth;
    RHeight = Height = GHeight;
    LeftOfs = TopOfs = 0;
    Resolution = BitsPerPixel;

    CountDown = (long)Width * (long)Height;
    Pass = 0;
    if( BitsPerPixel <= 1 )
        InitCodeSize = 2;
    else
        InitCodeSize = BitsPerPixel;
    curx = cury = 0;
    fwrite( "GIF87a", 1, 6, fp );
    Putword( RWidth, fp );
    Putword( RHeight, fp );
    B = 0x80;       /* Yes, there is a color map */
    B |= (Resolution - 1) << 5;
    B |= (BitsPerPixel - 1);
    fputc( B, fp );
    fputc( Background, fp );
    fputc( 0, fp );
    for( i=0; i<ColorMapSize; i++ ) {
        fputc( Red[i], fp );
        fputc( Green[i], fp );
        fputc( Blue[i], fp );
    }
    fputc( ',', fp );
    Putword( LeftOfs, fp );
    Putword( TopOfs, fp );
    Putword( Width, fp );
    Putword( Height, fp );
    if( Interlace )
        fputc( 0x40, fp );
    else
        fputc( 0x00, fp );
    fputc( InitCodeSize, fp );
    compress( InitCodeSize+1, fp, GetPixel );
    fputc( 0, fp );
    fputc( ';', fp );
    fclose( fp );
}

/*
 * Write out a word to the GIF file
 */
static void
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 ([email protected])
 *
 ***************************************************************************/

#define CBITS    12
#define HSIZE  5003            /* 80% occupancy */

/*
 *
 * 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))

int n_bits;                        /* number of bits/code */
int maxbits = CBITS;                /* user settable max # bits/code */
code_int maxcode;                  /* maximum code, given n_bits */
code_int maxmaxcode = (code_int)1 << CBITS; /* should NEVER generate this code */
# define MAXCODE(n_bits)        (((code_int) 1 << (n_bits)) - 1)

count_int htab [HSIZE];
unsigned short codetab [HSIZE];
#define HashTabOf(i)       htab[i]
#define CodeTabOf(i)    codetab[i]

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**CBITS 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<<CBITS))

code_int free_ent = 0;                  /* first unused entry */

/*
 * block compression parameters -- after all codes are used up,
 * and compression rate changes, start over.
 */
int clear_flg = 0;
int offset;
long int in_count = 1;            /* length of input */
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.
 */

int g_init_bits;
FILE *g_outfile;
int ClearCode;
int EOFCode;

static void
compress(
        int init_bits,
        FILE *outfile,
        ifun_t* ReadValue
)
{
    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( ReadValue );
    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 );
    while ( (c = GIFNextPixel( ReadValue )) != EOF ) {
        in_count++;
        fcode = (long) (((long) c << maxbits) + ent);
        /* i = (((code_int)c << hshift) ~ ent); */   /* xor hashing */
        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;
        if ( free_ent < maxmaxcode ) {
            CodeTabOf (i) = 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 );
    return;
}

/*****************************************************************
 * 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 CBITS 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.
 */

unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
                                  0x001F, 0x003F, 0x007F, 0x00FF,
                                  0x01FF, 0x03FF, 0x07FF, 0x0FFF,
                                  0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };

static void
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 ) )
                writeerr();
    }
}

/*
 * Clear out the hash table
 */
static void
cl_block (void)             /* table clear for block compress */
{
        cl_hash ( (count_int) hsize );
        free_ent = ClearCode + 2;
        clear_flg = 1;
        output( (code_int)ClearCode );
}

static void
cl_hash(          /* reset code table */
        register count_int hsize
)
{
        register count_int *htab_p = htab+hsize;
        register long i;
        register long m1 = -1;

        i = 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(void)
{
        printf( "error writing output file\n" );
        exit(1);
}

/******************************************************************************
 *
 * GIF Specific routines
 *
 ******************************************************************************/

/*
 * Number of characters so far in this 'packet'
 */
int a_count;

/*
 * Set up the 'byte output' routine
 */
static void
char_init(void)
{
        a_count = 0;
}

/*
 * Define the storage for the packet accumulator
 */
char accum[256];

/*
 * Add a character to the end of the current packet, and if it is 254
 * characters, flush the packet to disk.
 */
static void
char_out(
        int c
)
{
        accum[ a_count++ ] = c;
        if( a_count >= 254 )
                flush_char();
}

/*
 * Flush the packet to disk, and reset the accumulator
 */
static void
flush_char(void)
{
        if( a_count > 0 ) {
                fputc( a_count, g_outfile );
                fwrite( accum, 1, a_count, g_outfile );
                a_count = 0;
        }
}

static float curgamma;
static short gamtab[256];

static void
gammawarp(
        short *sbuf,
        float gam,
        int n
)
{
    int i;

    if(gam!=curgamma) {
        for(i=0; i<256; i++) 
            gamtab[i] = 255*pow(i/255.0,gam)+0.5;
        curgamma = gam;
    }
    while(n--) {
        *sbuf = gamtab[*sbuf];
        sbuf++;
    }
}
Revision:	2.13
Committed:	Fri Jul 19 17:37:56 2019 UTC (4 years, 9 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad5R4, rad5R3, HEAD
Changes since 2.12:	+2 -3 lines
Log Message:	Moved declarations and definitions for header.c from resolu.h to rtio.h
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.13	static const char RCSid[] = "$Id: ra_gif.c,v 2.12 2011/05/20 02:06:39 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Convert from Radiance picture file to Compuserve GIF.
6			* Currently, we don't know how to get back.
7			*/
8
9	schorsch	2.8	#include <math.h>
10	greg	2.1
11	greg	2.13	#include "rtio.h"
12	schorsch	2.8	#include "platform.h"
13	greg	2.1	#include "color.h"
14			#include "resolu.h"
15	schorsch	2.11	#include "clrtab.h"
16	greg	2.1
17			#define MAXCOLORS 256
18
19			int rmap[MAXCOLORS];
20			int gmap[MAXCOLORS];
21			int bmap[MAXCOLORS];
22
23			int currow;
24			long picstart;
25	greg	2.12	uby8 clrtab[256][3];
26	greg	2.1
27	greg	2.4	extern int samplefac;
28
29	greg	2.1
30			COLR *scanln;
31	greg	2.12	uby8 *pixscan;
32	greg	2.1
33			int xmax, ymax; /* picture size */
34			double gamv = 2.2; /* gamma correction */
35			int greyscale = 0; /* convert to B&W? */
36	greg	2.2	int dither = 1; /* dither colors? */
37	greg	2.1	int bradj = 0; /* brightness adjustment */
38	greg	2.6	int ncolors = 0; /* number of colors requested */
39
40	greg	2.1	char *progname;
41
42	schorsch	2.11	typedef int ifun_t(int x, int y); /* required by the GIF code below */
43
44			static void getrow(int y);
45			static void mkclrmap(int nc);
46			static void mkgrymap(int nc);
47			static ifun_t getgifpix;
48
49			static void GIFEncode(FILE *fp, int GWidth, int GHeight, int GInterlace,
50			int Background, int BitsPerPixel, int Red[], int Green[], int Blue[],
51			ifun_t* GetPixel);
52	greg	2.1
53	schorsch	2.11
54			int
55			main(int argc, char *argv[])
56	greg	2.1	{
57			int bitsperpix;
58			int i;
59	schorsch	2.8	SET_DEFAULT_BINARY();
60			SET_FILE_BINARY(stdin);
61			SET_FILE_BINARY(stdout);
62	greg	2.1	progname = argv[0];
63	greg	2.4	samplefac = 0;
64	greg	2.1
65			for (i = 1; i < argc; i++)
66			if (argv[i][0] == '-')
67			switch (argv[i][1]) {
68			case 'g':
69			gamv = atof(argv[++i]);
70			break;
71			case 'b':
72			greyscale = 1;
73			break;
74	greg	2.2	case 'd':
75			dither = !dither;
76			break;
77	greg	2.1	case 'c':
78			ncolors = atoi(argv[++i]);
79			break;
80			case 'e':
81			if (argv[i+1][0] != '+' && argv[i+1][0] != '-')
82			goto userr;
83			bradj = atoi(argv[++i]);
84			break;
85	greg	2.4	case 'n':
86			samplefac = atoi(argv[++i]);
87			break;
88	greg	2.1	default:
89			goto userr;
90			}
91			else
92			break;
93
94			if (i < argc-2)
95			goto userr;
96			if (i <= argc-1 && freopen(argv[i], "r", stdin) == NULL) {
97			fprintf(stderr, "%s: cannot open input \"%s\"\n",
98			progname, argv[i]);
99			exit(1);
100			}
101			if (i == argc-2 && freopen(argv[i+1], "w", stdout) == NULL) {
102			fprintf(stderr, "%s: cannot open output \"%s\"\n",
103			progname, argv[i+1]);
104			exit(1);
105			}
106			if (checkheader(stdin, COLRFMT, NULL) < 0 \|\|
107			fgetresolu(&xmax, &ymax, stdin) < 0) {
108			fprintf(stderr, "%s: bad picture format\n", progname);
109			exit(1);
110			}
111			picstart = ftell(stdin);
112			currow = -1;
113			scanln = (COLR )malloc(xmaxsizeof(COLR));
114			if (scanln == NULL) {
115			fprintf(stderr, "%s: out of memory\n", progname);
116			exit(1);
117			}
118			/* set up gamma correction */
119			setcolrgam(gamv);
120			/* figure out the bits per pixel */
121	schorsch	2.10	if ((ncolors < 2) \| (ncolors > MAXCOLORS))
122	greg	2.1	ncolors = MAXCOLORS;
123			for (bitsperpix = 1; ncolors > 1<<bitsperpix; bitsperpix++)
124			;
125			/* compute color map */
126			if (greyscale)
127			mkgrymap(ncolors);
128			else
129			mkclrmap(ncolors);
130			/* convert image */
131			GIFEncode(stdout, xmax, ymax, 0, 0, bitsperpix,
132			rmap, gmap, bmap, getgifpix);
133			exit(0);
134			userr:
135			fprintf(stderr,
136	greg	2.5	"Usage: %s [-b][-d][-n samp][-c ncolors][-g gamv][-e +/-stops] input [output]\n",
137	greg	2.1	progname);
138			exit(1);
139			}
140
141
142	schorsch	2.11	static void
143			getrow( /* get the specified row from our image */
144			int y
145			)
146	greg	2.1	{
147			if (y == currow)
148			return;
149			if (y < currow) {
150			fseek(stdin, picstart, 0);
151			currow = -1;
152			}
153			do
154			if (freadcolrs(scanln, xmax, stdin) < 0) {
155			fprintf(stderr, "%s: error reading picture (y==%d)\n",
156			progname, ymax-1-y);
157	greg	2.3	exit(1);
158	greg	2.1	}
159			while (++currow < y);
160			if (bradj)
161			shiftcolrs(scanln, xmax, bradj);
162			colrs_gambs(scanln, xmax);
163	schorsch	2.9	if (pixscan != NULL) {
164	greg	2.4	if (samplefac)
165			neu_dith_colrs(pixscan, scanln, xmax);
166			else
167			dith_colrs(pixscan, scanln, xmax);
168	schorsch	2.9	}
169	greg	2.1	}
170
171
172	schorsch	2.11	static void
173			mkclrmap( /* make our color map */
174			int nc
175			)
176	greg	2.1	{
177			register int i;
178
179	greg	2.4	if ((samplefac ? neu_init(xmaxymax) : new_histo(xmaxymax)) == -1)
180			goto memerr;
181	greg	2.1	for (i = 0; i < ymax; i++) {
182			getrow(i);
183	greg	2.4	if (samplefac)
184			neu_colrs(scanln, xmax);
185			else
186			cnt_colrs(scanln, xmax);
187	greg	2.1	}
188	greg	2.4	if (samplefac)
189			neu_clrtab(nc);
190			else
191			new_clrtab(nc);
192	greg	2.1	for (i = 0; i < nc; i++) {
193			rmap[i] = clrtab[i][RED];
194			gmap[i] = clrtab[i][GRN];
195			bmap[i] = clrtab[i][BLU];
196			}
197	greg	2.12	if (dither && (pixscan = (uby8 *)malloc(xmax)) == NULL)
198	greg	2.4	goto memerr;
199			return;
200			memerr:
201			fprintf(stderr, "%s: out of memory\n", progname);
202			exit(1);
203	greg	2.1	}
204
205
206	schorsch	2.11	static void
207			mkgrymap(
208			int nc
209			)
210	greg	2.1	{
211			register int i;
212
213			for (i = 0; i < nc; i++) {
214			rmap[i] =
215			gmap[i] =
216			bmap[i] = ((unsigned)i<<8)/nc;
217			}
218			}
219
220
221	schorsch	2.11	static int
222			getgifpix( /* get a single pixel from our picture */
223			int x,
224			int y
225			)
226	greg	2.1	{
227			getrow(y);
228			if (greyscale)
229	greg	2.6	return((normbright(scanln[x])*ncolors)>>8);
230	greg	2.2	if (pixscan != NULL)
231			return(pixscan[x]);
232	greg	2.4	return(samplefac ? neu_map_pixel(scanln[x]) : map_pixel(scanln[x]));
233	greg	2.1	}
234
235
236			/*
237			* SCARY GIF code follows . . . . sorry.
238			*
239			* Based on GIFENCOD by David Rowley <[email protected]>.A
240	schorsch	2.11	* Lempel-Ziv compression based on "compress".
241	greg	2.1	*
242			*/
243
244			/*****************************************************************************
245			*
246			* GIFENCODE.C - GIF Image compression interface
247			*
248			* GIFEncode( FName, GHeight, GWidth, GInterlace, Background,
249			* BitsPerPixel, Red, Green, Blue, GetPixel )
250			*
251			*****************************************************************************/
252
253			#define TRUE 1
254			#define FALSE 0
255
256			int Width, Height;
257			int curx, cury;
258			long CountDown;
259			int Pass;
260			int Interlace;
261			unsigned long cur_accum = 0;
262			int cur_bits = 0;
263
264	schorsch	2.11	static void BumpPixel(void);
265			static int GIFNextPixel(ifun_t* getpixel);
266			static void Putword(int w, FILE *fp);
267			static void compress(int init_bits, FILE outfile, ifun_t ReadValue);
268
269
270			/* a code_int must be able to hold 2*CBITS values of type int, and also -1 /
271			typedef int code_int;
272			typedef long int count_int;
273			typedef unsigned char char_type;
274
275			static void output(code_int code);
276			static void cl_block(void);
277			static void cl_hash(count_int hsize);
278			static void writeerr(void);
279
280			static void char_init(void);
281			static void char_out(int c);
282			static void flush_char(void);
283			static void gammawarp(short *sbuf, float gam, int n);
284
285
286	greg	2.1	/*
287			* Bump the 'curx' and 'cury' to point to the next pixel
288			*/
289	schorsch	2.11	static void
290			BumpPixel(void)
291	greg	2.1	{
292			curx++;
293			if( curx == Width ) {
294			curx = 0;
295			if( !Interlace ) {
296			cury++;
297			} else {
298			switch( Pass ) {
299			case 0:
300			cury += 8;
301			if( cury >= Height ) {
302			Pass++;
303			cury = 4;
304			}
305			break;
306			case 1:
307			cury += 8;
308			if( cury >= Height ) {
309			Pass++;
310			cury = 2;
311			}
312			break;
313			case 2:
314			cury += 4;
315			if( cury >= Height ) {
316			Pass++;
317			cury = 1;
318			}
319			break;
320			case 3:
321			cury += 2;
322			break;
323			}
324			}
325			}
326			}
327
328			/*
329			* Return the next pixel from the image
330			*/
331	schorsch	2.11	static int
332			GIFNextPixel(
333			ifun_t* getpixel
334			)
335	greg	2.1	{
336			int r;
337
338			if( CountDown == 0 )
339			return EOF;
340			CountDown--;
341			r = (*getpixel)( curx, cury );
342			BumpPixel();
343			return r;
344			}
345
346			/*
347			* public GIFEncode
348			*/
349	schorsch	2.11	static void
350			GIFEncode(
351			FILE *fp,
352			int GWidth,
353			int GHeight,
354			int GInterlace,
355			int Background,
356			int BitsPerPixel,
357			int Red[],
358			int Green[],
359			int Blue[],
360			ifun_t* GetPixel
361			)
362	greg	2.1	{
363			int B;
364			int RWidth, RHeight;
365			int LeftOfs, TopOfs;
366			int Resolution;
367			int ColorMapSize;
368			int InitCodeSize;
369			int i;
370
371	schorsch	2.11	cur_accum = 0; /* globals */
372	greg	2.1	cur_bits = 0;
373
374			Interlace = GInterlace;
375			ColorMapSize = 1 << BitsPerPixel;
376			RWidth = Width = GWidth;
377			RHeight = Height = GHeight;
378			LeftOfs = TopOfs = 0;
379			Resolution = BitsPerPixel;
380
381			CountDown = (long)Width * (long)Height;
382			Pass = 0;
383			if( BitsPerPixel <= 1 )
384			InitCodeSize = 2;
385			else
386			InitCodeSize = BitsPerPixel;
387			curx = cury = 0;
388			fwrite( "GIF87a", 1, 6, fp );
389			Putword( RWidth, fp );
390			Putword( RHeight, fp );
391			B = 0x80; /* Yes, there is a color map */
392			B \|= (Resolution - 1) << 5;
393			B \|= (BitsPerPixel - 1);
394			fputc( B, fp );
395			fputc( Background, fp );
396			fputc( 0, fp );
397			for( i=0; i<ColorMapSize; i++ ) {
398			fputc( Red[i], fp );
399			fputc( Green[i], fp );
400			fputc( Blue[i], fp );
401			}
402			fputc( ',', fp );
403			Putword( LeftOfs, fp );
404			Putword( TopOfs, fp );
405			Putword( Width, fp );
406			Putword( Height, fp );
407			if( Interlace )
408			fputc( 0x40, fp );
409			else
410			fputc( 0x00, fp );
411			fputc( InitCodeSize, fp );
412			compress( InitCodeSize+1, fp, GetPixel );
413			fputc( 0, fp );
414			fputc( ';', fp );
415			fclose( fp );
416			}
417
418			/*
419			* Write out a word to the GIF file
420			*/
421	schorsch	2.11	static void
422			Putword(
423			int w,
424			FILE *fp
425			)
426	greg	2.1	{
427			fputc( w & 0xff, fp );
428			fputc( (w/256) & 0xff, fp );
429			}
430
431
432			/***************************************************************************
433			*
434			* GIFCOMPR.C - GIF Image compression routines
435			*
436			* Lempel-Ziv compression based on 'compress'. GIF modifications by
437			* David Rowley ([email protected])
438			*
439			***************************************************************************/
440
441			#define CBITS 12
442			#define HSIZE 5003 /* 80% occupancy */
443
444			/*
445			*
446			* GIF Image compression - modified 'compress'
447			*
448			* Based on: compress.c - File compression ala IEEE Computer, June 1984.
449			*
450			* By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
451			* Jim McKie (decvax!mcvax!jim)
452			* Steve Davies (decvax!vax135!petsd!peora!srd)
453			* Ken Turkowski (decvax!decwrl!turtlevax!ken)
454			* James A. Woods (decvax!ihnp4!ames!jaw)
455			* Joe Orost (decvax!vax135!petsd!joe)
456			*
457			*/
458			#include <ctype.h>
459
460			#define ARGVAL() (++(argv) \|\| (--argc && *++argv))
461
462			int n_bits; /* number of bits/code */
463			int maxbits = CBITS; /* user settable max # bits/code */
464			code_int maxcode; /* maximum code, given n_bits */
465			code_int maxmaxcode = (code_int)1 << CBITS; /* should NEVER generate this code */
466			# define MAXCODE(n_bits) (((code_int) 1 << (n_bits)) - 1)
467
468			count_int htab [HSIZE];
469			unsigned short codetab [HSIZE];
470			#define HashTabOf(i) htab[i]
471			#define CodeTabOf(i) codetab[i]
472
473			code_int hsize = HSIZE; /* for dynamic table sizing */
474
475			/*
476			* To save much memory, we overlay the table used by compress() with those
477			* used by decompress(). The tab_prefix table is the same size and type
478			* as the codetab. The tab_suffix table needs 2**CBITS characters. We
479			* get this from the beginning of htab. The output stack uses the rest
480			* of htab, and contains characters. There is plenty of room for any
481			* possible stack (stack used to be 8000 characters).
482			*/
483			#define tab_prefixof(i) CodeTabOf(i)
484			#define tab_suffixof(i) ((char_type *)(htab))[i]
485			#define de_stack ((char_type *)&tab_suffixof((code_int)1<<CBITS))
486
487			code_int free_ent = 0; /* first unused entry */
488
489			/*
490			* block compression parameters -- after all codes are used up,
491			* and compression rate changes, start over.
492			*/
493			int clear_flg = 0;
494			int offset;
495			long int in_count = 1; /* length of input */
496			long int out_count = 0; /* # of codes output (for debugging) */
497
498			/*
499			* compress stdin to stdout
500			*
501			* Algorithm: use open addressing double hashing (no chaining) on the
502			* prefix code / next character combination. We do a variant of Knuth's
503			* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
504			* secondary probe. Here, the modular division first probe is gives way
505			* to a faster exclusive-or manipulation. Also do block compression with
506			* an adaptive reset, whereby the code table is cleared when the compression
507			* ratio decreases, but after the table fills. The variable-length output
508			* codes are re-sized at this point, and a special CLEAR code is generated
509			* for the decompressor. Late addition: construct the table according to
510			* file size for noticeable speed improvement on small files. Please direct
511			* questions about this implementation to ames!jaw.
512			*/
513
514			int g_init_bits;
515			FILE *g_outfile;
516			int ClearCode;
517			int EOFCode;
518
519	schorsch	2.11	static void
520			compress(
521			int init_bits,
522			FILE *outfile,
523			ifun_t* ReadValue
524			)
525	greg	2.1	{
526			register long fcode;
527			register code_int i = 0;
528			register int c;
529			register code_int ent;
530			register code_int disp;
531			register code_int hsize_reg;
532			register int hshift;
533
534			/*
535			* Set up the globals: g_init_bits - initial number of bits
536			* g_outfile - pointer to output file
537			*/
538			g_init_bits = init_bits;
539			g_outfile = outfile;
540			/*
541			* Set up the necessary values
542			*/
543			offset = 0;
544			out_count = 0;
545			clear_flg = 0;
546			in_count = 1;
547			maxcode = MAXCODE(n_bits = g_init_bits);
548			ClearCode = (1 << (init_bits - 1));
549			EOFCode = ClearCode + 1;
550			free_ent = ClearCode + 2;
551			char_init();
552			ent = GIFNextPixel( ReadValue );
553			hshift = 0;
554			for ( fcode = (long) hsize; fcode < 65536L; fcode *= 2L )
555			hshift++;
556			hshift = 8 - hshift; /* set hash code range bound */
557			hsize_reg = hsize;
558			cl_hash( (count_int) hsize_reg); /* clear hash table */
559			output( (code_int)ClearCode );
560			while ( (c = GIFNextPixel( ReadValue )) != EOF ) {
561			in_count++;
562			fcode = (long) (((long) c << maxbits) + ent);
563	schorsch	2.11	/* i = (((code_int)c << hshift) ~ ent); / / xor hashing */
564	greg	2.1	i = (((code_int)c << hshift) ^ ent); /* xor hashing */
565			if ( HashTabOf (i) == fcode ) {
566			ent = CodeTabOf (i);
567			continue;
568			} else if ( (long)HashTabOf (i) < 0 ) /* empty slot */
569			goto nomatch;
570			disp = hsize_reg - i; /* secondary hash (after G. Knott) */
571			if ( i == 0 )
572			disp = 1;
573			probe:
574			if ( (i -= disp) < 0 )
575			i += hsize_reg;
576			if ( HashTabOf (i) == fcode ) {
577			ent = CodeTabOf (i);
578			continue;
579			}
580			if ( (long)HashTabOf (i) > 0 )
581			goto probe;
582			nomatch:
583			output ( (code_int) ent );
584			out_count++;
585			ent = c;
586			if ( free_ent < maxmaxcode ) {
587			CodeTabOf (i) = free_ent++; /* code -> hashtable */
588			HashTabOf (i) = fcode;
589			} else
590			cl_block();
591			}
592			/*
593			* Put out the final code.
594			*/
595			output( (code_int)ent );
596			out_count++;
597			output( (code_int) EOFCode );
598			return;
599			}
600
601			/*****************************************************************
602			* TAG( output )
603			*
604			* Output the given code.
605			* Inputs:
606			* code: A n_bits-bit integer. If == -1, then EOF. This assumes
607			* that n_bits =< (long)wordsize - 1.
608			* Outputs:
609			* Outputs code to the file.
610			* Assumptions:
611			* Chars are 8 bits long.
612			* Algorithm:
613			* Maintain a CBITS character long buffer (so that 8 codes will
614			* fit in it exactly). Use the VAX insv instruction to insert each
615			* code in turn. When the buffer fills up empty it and start over.
616			*/
617
618			unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
619			0x001F, 0x003F, 0x007F, 0x00FF,
620			0x01FF, 0x03FF, 0x07FF, 0x0FFF,
621			0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
622
623	schorsch	2.11	static void
624			output(
625			code_int code
626			)
627	greg	2.1	{
628			cur_accum &= masks[ cur_bits ];
629			if( cur_bits > 0 )
630			cur_accum \|= ((long)code << cur_bits);
631			else
632			cur_accum = code;
633			cur_bits += n_bits;
634			while( cur_bits >= 8 ) {
635			char_out( (unsigned int)(cur_accum & 0xff) );
636			cur_accum >>= 8;
637			cur_bits -= 8;
638			}
639
640			/*
641			* If the next entry is going to be too big for the code size,
642			* then increase it, if possible.
643			*/
644			if ( free_ent > maxcode \|\| clear_flg ) {
645			if( clear_flg ) {
646			maxcode = MAXCODE (n_bits = g_init_bits);
647			clear_flg = 0;
648			} else {
649			n_bits++;
650			if ( n_bits == maxbits )
651			maxcode = maxmaxcode;
652			else
653			maxcode = MAXCODE(n_bits);
654			}
655			}
656			if( code == EOFCode ) {
657			/*
658			* At EOF, write the rest of the buffer.
659			*/
660			while( cur_bits > 0 ) {
661			char_out( (unsigned int)(cur_accum & 0xff) );
662			cur_accum >>= 8;
663			cur_bits -= 8;
664			}
665			flush_char();
666			fflush( g_outfile );
667			if( ferror( g_outfile ) )
668			writeerr();
669			}
670			}
671
672			/*
673			* Clear out the hash table
674			*/
675	schorsch	2.11	static void
676			cl_block (void) /* table clear for block compress */
677	greg	2.1	{
678			cl_hash ( (count_int) hsize );
679			free_ent = ClearCode + 2;
680			clear_flg = 1;
681			output( (code_int)ClearCode );
682			}
683
684	schorsch	2.11	static void
685			cl_hash( /* reset code table */
686			register count_int hsize
687			)
688	greg	2.1	{
689			register count_int *htab_p = htab+hsize;
690			register long i;
691			register long m1 = -1;
692
693			i = hsize - 16;
694			do { /* might use Sys V memset(3) here */
695			*(htab_p-16) = m1;
696			*(htab_p-15) = m1;
697			*(htab_p-14) = m1;
698			*(htab_p-13) = m1;
699			*(htab_p-12) = m1;
700			*(htab_p-11) = m1;
701			*(htab_p-10) = m1;
702			*(htab_p-9) = m1;
703			*(htab_p-8) = m1;
704			*(htab_p-7) = m1;
705			*(htab_p-6) = m1;
706			*(htab_p-5) = m1;
707			*(htab_p-4) = m1;
708			*(htab_p-3) = m1;
709			*(htab_p-2) = m1;
710			*(htab_p-1) = m1;
711			htab_p -= 16;
712			} while ((i -= 16) >= 0);
713			for ( i += 16; i > 0; i-- )
714			*--htab_p = m1;
715			}
716
717	schorsch	2.11	static void
718			writeerr(void)
719	greg	2.1	{
720			printf( "error writing output file\n" );
721			exit(1);
722			}
723
724			/******************************************************************************
725			*
726			* GIF Specific routines
727			*
728			******************************************************************************/
729
730			/*
731			* Number of characters so far in this 'packet'
732			*/
733			int a_count;
734
735			/*
736			* Set up the 'byte output' routine
737			*/
738	schorsch	2.11	static void
739			char_init(void)
740	greg	2.1	{
741			a_count = 0;
742			}
743
744			/*
745			* Define the storage for the packet accumulator
746			*/
747			char accum[256];
748
749			/*
750			* Add a character to the end of the current packet, and if it is 254
751			* characters, flush the packet to disk.
752			*/
753	schorsch	2.11	static void
754			char_out(
755			int c
756			)
757	greg	2.1	{
758			accum[ a_count++ ] = c;
759			if( a_count >= 254 )
760			flush_char();
761			}
762
763			/*
764			* Flush the packet to disk, and reset the accumulator
765			*/
766	schorsch	2.11	static void
767			flush_char(void)
768	greg	2.1	{
769			if( a_count > 0 ) {
770			fputc( a_count, g_outfile );
771			fwrite( accum, 1, a_count, g_outfile );
772			a_count = 0;
773			}
774			}
775
776			static float curgamma;
777			static short gamtab[256];
778
779	schorsch	2.11	static void
780			gammawarp(
781			short *sbuf,
782			float gam,
783			int n
784			)
785	greg	2.1	{
786			int i;
787
788			if(gam!=curgamma) {
789			for(i=0; i<256; i++)
790			gamtab[i] = 255*pow(i/255.0,gam)+0.5;
791			curgamma = gam;
792			}
793			while(n--) {
794			sbuf = gamtab[sbuf];
795			sbuf++;
796			}
797			}