src/px/ra_gif.c

#ifndef lint
static const char       RCSid[] = "$Id: ra_gif.c,v 2.7 2003/02/22 02:07:27 greg Exp $";
#endif
/*
 * Convert from Radiance picture file to Compuserve GIF.
 * Currently, we don't know how to get back.
 */

#include  <stdio.h>
#include  <time.h>
#include  <math.h>

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

#define MAXCOLORS               256

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

int currow;

extern long  ftell();

long  picstart;

BYTE  clrtab[256][3];

extern int  samplefac;

extern int  getgifpix();

COLR    *scanln;
BYTE    *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;


main(argc, argv)
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);
}


getrow(y)                       /* 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);
}


mkclrmap(nc)                    /* 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 = (BYTE *)malloc(xmax)) == NULL)
                goto memerr;
        return;
memerr:
        fprintf(stderr, "%s: out of memory\n", progname);
        exit(1);
}


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

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


int
getgifpix(x, y)                 /* get a single pixel from our picture */
int  x, y;
{
        int pix;

        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-Zim compression based on "compress".
 *
 */

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

#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;

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

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

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

    long cur_accum = 0;
    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
 */
Putword( w, fp )
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 */

/*
 * 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;

/*
 *
 * 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;

compress( init_bits, outfile, ReadValue )
int init_bits;
FILE *outfile;
ifunptr 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 };

output( code )
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
 */
cl_block ()             /* table clear for block compress */
{
        cl_hash ( (count_int) hsize );
        free_ent = ClearCode + 2;
        clear_flg = 1;
        output( (code_int)ClearCode );
}

cl_hash(hsize)          /* 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;
}

writeerr()
{
        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
 */
char_init()
{
        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.
 */
char_out( c )
int c;
{
        accum[ a_count++ ] = c;
        if( a_count >= 254 )
                flush_char();
}

/*
 * Flush the packet to disk, and reset the accumulator
 */
flush_char()
{
        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];

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

    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:	2.8
Committed:	Thu Jun 5 19:29:34 2003 UTC (22 years, 4 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.7:	+6 -15 lines
Log Message:	Macros for setting binary file mode. Replacing MSDOS by _WIN32.
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	schorsch	2.8	static const char RCSid[] = "$Id: ra_gif.c,v 2.7 2003/02/22 02:07:27 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			#include <stdio.h>
10	greg	2.7	#include <time.h>
11	schorsch	2.8	#include <math.h>
12	greg	2.1
13	schorsch	2.8	#include "platform.h"
14	greg	2.1	#include "color.h"
15			#include "resolu.h"
16
17			#define MAXCOLORS 256
18
19			int rmap[MAXCOLORS];
20			int gmap[MAXCOLORS];
21			int bmap[MAXCOLORS];
22
23			int currow;
24
25			extern long ftell();
26
27			long picstart;
28
29	greg	2.4	BYTE clrtab[256][3];
30	greg	2.1
31	greg	2.4	extern int samplefac;
32
33	greg	2.1	extern int getgifpix();
34
35			COLR *scanln;
36	greg	2.2	BYTE *pixscan;
37	greg	2.1
38			int xmax, ymax; /* picture size */
39
40			double gamv = 2.2; /* gamma correction */
41
42			int greyscale = 0; /* convert to B&W? */
43
44	greg	2.2	int dither = 1; /* dither colors? */
45
46	greg	2.1	int bradj = 0; /* brightness adjustment */
47
48	greg	2.6	int ncolors = 0; /* number of colors requested */
49
50	greg	2.1	char *progname;
51
52
53			main(argc, argv)
54			int argc;
55			char *argv[];
56			{
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			if (ncolors < 2 \| ncolors > MAXCOLORS)
122			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			getrow(y) /* get the specified row from our image */
143			int y;
144			{
145			if (y == currow)
146			return;
147			if (y < currow) {
148			fseek(stdin, picstart, 0);
149			currow = -1;
150			}
151			do
152			if (freadcolrs(scanln, xmax, stdin) < 0) {
153			fprintf(stderr, "%s: error reading picture (y==%d)\n",
154			progname, ymax-1-y);
155	greg	2.3	exit(1);
156	greg	2.1	}
157			while (++currow < y);
158			if (bradj)
159			shiftcolrs(scanln, xmax, bradj);
160			colrs_gambs(scanln, xmax);
161	greg	2.2	if (pixscan != NULL)
162	greg	2.4	if (samplefac)
163			neu_dith_colrs(pixscan, scanln, xmax);
164			else
165			dith_colrs(pixscan, scanln, xmax);
166	greg	2.1	}
167
168
169			mkclrmap(nc) /* make our color map */
170			int nc;
171			{
172			register int i;
173
174	greg	2.4	if ((samplefac ? neu_init(xmaxymax) : new_histo(xmaxymax)) == -1)
175			goto memerr;
176	greg	2.1	for (i = 0; i < ymax; i++) {
177			getrow(i);
178	greg	2.4	if (samplefac)
179			neu_colrs(scanln, xmax);
180			else
181			cnt_colrs(scanln, xmax);
182	greg	2.1	}
183	greg	2.4	if (samplefac)
184			neu_clrtab(nc);
185			else
186			new_clrtab(nc);
187	greg	2.1	for (i = 0; i < nc; i++) {
188			rmap[i] = clrtab[i][RED];
189			gmap[i] = clrtab[i][GRN];
190			bmap[i] = clrtab[i][BLU];
191			}
192	greg	2.4	if (dither && (pixscan = (BYTE *)malloc(xmax)) == NULL)
193			goto memerr;
194			return;
195			memerr:
196			fprintf(stderr, "%s: out of memory\n", progname);
197			exit(1);
198	greg	2.1	}
199
200
201			mkgrymap(nc)
202			int nc;
203			{
204			register int i;
205
206			for (i = 0; i < nc; i++) {
207			rmap[i] =
208			gmap[i] =
209			bmap[i] = ((unsigned)i<<8)/nc;
210			}
211			}
212
213
214			int
215			getgifpix(x, y) /* get a single pixel from our picture */
216			int x, y;
217			{
218			int pix;
219
220			getrow(y);
221			if (greyscale)
222	greg	2.6	return((normbright(scanln[x])*ncolors)>>8);
223	greg	2.2	if (pixscan != NULL)
224			return(pixscan[x]);
225	greg	2.4	return(samplefac ? neu_map_pixel(scanln[x]) : map_pixel(scanln[x]));
226	greg	2.1	}
227
228
229			/*
230			* SCARY GIF code follows . . . . sorry.
231			*
232			* Based on GIFENCOD by David Rowley <[email protected]>.A
233			* Lempel-Zim compression based on "compress".
234			*
235			*/
236
237			/*****************************************************************************
238			*
239			* GIFENCODE.C - GIF Image compression interface
240			*
241			* GIFEncode( FName, GHeight, GWidth, GInterlace, Background,
242			* BitsPerPixel, Red, Green, Blue, GetPixel )
243			*
244			*****************************************************************************/
245			typedef int (* ifunptr)();
246
247			#define TRUE 1
248			#define FALSE 0
249
250			int Width, Height;
251			int curx, cury;
252			long CountDown;
253			int Pass;
254			int Interlace;
255			unsigned long cur_accum = 0;
256			int cur_bits = 0;
257
258			/*
259			* Bump the 'curx' and 'cury' to point to the next pixel
260			*/
261			BumpPixel()
262			{
263			curx++;
264			if( curx == Width ) {
265			curx = 0;
266			if( !Interlace ) {
267			cury++;
268			} else {
269			switch( Pass ) {
270			case 0:
271			cury += 8;
272			if( cury >= Height ) {
273			Pass++;
274			cury = 4;
275			}
276			break;
277			case 1:
278			cury += 8;
279			if( cury >= Height ) {
280			Pass++;
281			cury = 2;
282			}
283			break;
284			case 2:
285			cury += 4;
286			if( cury >= Height ) {
287			Pass++;
288			cury = 1;
289			}
290			break;
291			case 3:
292			cury += 2;
293			break;
294			}
295			}
296			}
297			}
298
299			/*
300			* Return the next pixel from the image
301			*/
302			GIFNextPixel( getpixel )
303			ifunptr getpixel;
304			{
305			int r;
306
307			if( CountDown == 0 )
308			return EOF;
309			CountDown--;
310			r = (*getpixel)( curx, cury );
311			BumpPixel();
312			return r;
313			}
314
315			/*
316			* public GIFEncode
317			*/
318			GIFEncode( fp, GWidth, GHeight, GInterlace, Background,
319			BitsPerPixel, Red, Green, Blue, GetPixel )
320			FILE *fp;
321			int GWidth, GHeight;
322			int GInterlace;
323			int Background;
324			int BitsPerPixel;
325			int Red[], Green[], Blue[];
326			ifunptr GetPixel;
327			{
328			int B;
329			int RWidth, RHeight;
330			int LeftOfs, TopOfs;
331			int Resolution;
332			int ColorMapSize;
333			int InitCodeSize;
334			int i;
335
336			long cur_accum = 0;
337			cur_bits = 0;
338
339			Interlace = GInterlace;
340			ColorMapSize = 1 << BitsPerPixel;
341			RWidth = Width = GWidth;
342			RHeight = Height = GHeight;
343			LeftOfs = TopOfs = 0;
344			Resolution = BitsPerPixel;
345
346			CountDown = (long)Width * (long)Height;
347			Pass = 0;
348			if( BitsPerPixel <= 1 )
349			InitCodeSize = 2;
350			else
351			InitCodeSize = BitsPerPixel;
352			curx = cury = 0;
353			fwrite( "GIF87a", 1, 6, fp );
354			Putword( RWidth, fp );
355			Putword( RHeight, fp );
356			B = 0x80; /* Yes, there is a color map */
357			B \|= (Resolution - 1) << 5;
358			B \|= (BitsPerPixel - 1);
359			fputc( B, fp );
360			fputc( Background, fp );
361			fputc( 0, fp );
362			for( i=0; i<ColorMapSize; i++ ) {
363			fputc( Red[i], fp );
364			fputc( Green[i], fp );
365			fputc( Blue[i], fp );
366			}
367			fputc( ',', fp );
368			Putword( LeftOfs, fp );
369			Putword( TopOfs, fp );
370			Putword( Width, fp );
371			Putword( Height, fp );
372			if( Interlace )
373			fputc( 0x40, fp );
374			else
375			fputc( 0x00, fp );
376			fputc( InitCodeSize, fp );
377			compress( InitCodeSize+1, fp, GetPixel );
378			fputc( 0, fp );
379			fputc( ';', fp );
380			fclose( fp );
381			}
382
383			/*
384			* Write out a word to the GIF file
385			*/
386			Putword( w, fp )
387			int w;
388			FILE *fp;
389			{
390			fputc( w & 0xff, fp );
391			fputc( (w/256) & 0xff, fp );
392			}
393
394
395			/***************************************************************************
396			*
397			* GIFCOMPR.C - GIF Image compression routines
398			*
399			* Lempel-Ziv compression based on 'compress'. GIF modifications by
400			* David Rowley ([email protected])
401			*
402			***************************************************************************/
403
404			#define CBITS 12
405			#define HSIZE 5003 /* 80% occupancy */
406
407			/*
408			* a code_int must be able to hold 2**CBITS values of type int, and also -1
409			*/
410			typedef int code_int;
411			typedef long int count_int;
412			typedef unsigned char char_type;
413
414			/*
415			*
416			* GIF Image compression - modified 'compress'
417			*
418			* Based on: compress.c - File compression ala IEEE Computer, June 1984.
419			*
420			* By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
421			* Jim McKie (decvax!mcvax!jim)
422			* Steve Davies (decvax!vax135!petsd!peora!srd)
423			* Ken Turkowski (decvax!decwrl!turtlevax!ken)
424			* James A. Woods (decvax!ihnp4!ames!jaw)
425			* Joe Orost (decvax!vax135!petsd!joe)
426			*
427			*/
428			#include <ctype.h>
429
430			#define ARGVAL() (++(argv) \|\| (--argc && *++argv))
431
432			int n_bits; /* number of bits/code */
433			int maxbits = CBITS; /* user settable max # bits/code */
434			code_int maxcode; /* maximum code, given n_bits */
435			code_int maxmaxcode = (code_int)1 << CBITS; /* should NEVER generate this code */
436			# define MAXCODE(n_bits) (((code_int) 1 << (n_bits)) - 1)
437
438			count_int htab [HSIZE];
439			unsigned short codetab [HSIZE];
440			#define HashTabOf(i) htab[i]
441			#define CodeTabOf(i) codetab[i]
442
443			code_int hsize = HSIZE; /* for dynamic table sizing */
444
445			/*
446			* To save much memory, we overlay the table used by compress() with those
447			* used by decompress(). The tab_prefix table is the same size and type
448			* as the codetab. The tab_suffix table needs 2**CBITS characters. We
449			* get this from the beginning of htab. The output stack uses the rest
450			* of htab, and contains characters. There is plenty of room for any
451			* possible stack (stack used to be 8000 characters).
452			*/
453			#define tab_prefixof(i) CodeTabOf(i)
454			#define tab_suffixof(i) ((char_type *)(htab))[i]
455			#define de_stack ((char_type *)&tab_suffixof((code_int)1<<CBITS))
456
457			code_int free_ent = 0; /* first unused entry */
458
459			/*
460			* block compression parameters -- after all codes are used up,
461			* and compression rate changes, start over.
462			*/
463			int clear_flg = 0;
464			int offset;
465			long int in_count = 1; /* length of input */
466			long int out_count = 0; /* # of codes output (for debugging) */
467
468			/*
469			* compress stdin to stdout
470			*
471			* Algorithm: use open addressing double hashing (no chaining) on the
472			* prefix code / next character combination. We do a variant of Knuth's
473			* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
474			* secondary probe. Here, the modular division first probe is gives way
475			* to a faster exclusive-or manipulation. Also do block compression with
476			* an adaptive reset, whereby the code table is cleared when the compression
477			* ratio decreases, but after the table fills. The variable-length output
478			* codes are re-sized at this point, and a special CLEAR code is generated
479			* for the decompressor. Late addition: construct the table according to
480			* file size for noticeable speed improvement on small files. Please direct
481			* questions about this implementation to ames!jaw.
482			*/
483
484			int g_init_bits;
485			FILE *g_outfile;
486			int ClearCode;
487			int EOFCode;
488
489			compress( init_bits, outfile, ReadValue )
490			int init_bits;
491			FILE *outfile;
492			ifunptr ReadValue;
493			{
494			register long fcode;
495			register code_int i = 0;
496			register int c;
497			register code_int ent;
498			register code_int disp;
499			register code_int hsize_reg;
500			register int hshift;
501
502			/*
503			* Set up the globals: g_init_bits - initial number of bits
504			* g_outfile - pointer to output file
505			*/
506			g_init_bits = init_bits;
507			g_outfile = outfile;
508			/*
509			* Set up the necessary values
510			*/
511			offset = 0;
512			out_count = 0;
513			clear_flg = 0;
514			in_count = 1;
515			maxcode = MAXCODE(n_bits = g_init_bits);
516			ClearCode = (1 << (init_bits - 1));
517			EOFCode = ClearCode + 1;
518			free_ent = ClearCode + 2;
519			char_init();
520			ent = GIFNextPixel( ReadValue );
521			hshift = 0;
522			for ( fcode = (long) hsize; fcode < 65536L; fcode *= 2L )
523			hshift++;
524			hshift = 8 - hshift; /* set hash code range bound */
525			hsize_reg = hsize;
526			cl_hash( (count_int) hsize_reg); /* clear hash table */
527			output( (code_int)ClearCode );
528			while ( (c = GIFNextPixel( ReadValue )) != EOF ) {
529			in_count++;
530			fcode = (long) (((long) c << maxbits) + ent);
531			/* i = (((code_int)c << hshift) ~ ent); /* xor hashing */
532			i = (((code_int)c << hshift) ^ ent); /* xor hashing */
533			if ( HashTabOf (i) == fcode ) {
534			ent = CodeTabOf (i);
535			continue;
536			} else if ( (long)HashTabOf (i) < 0 ) /* empty slot */
537			goto nomatch;
538			disp = hsize_reg - i; /* secondary hash (after G. Knott) */
539			if ( i == 0 )
540			disp = 1;
541			probe:
542			if ( (i -= disp) < 0 )
543			i += hsize_reg;
544			if ( HashTabOf (i) == fcode ) {
545			ent = CodeTabOf (i);
546			continue;
547			}
548			if ( (long)HashTabOf (i) > 0 )
549			goto probe;
550			nomatch:
551			output ( (code_int) ent );
552			out_count++;
553			ent = c;
554			if ( free_ent < maxmaxcode ) {
555			CodeTabOf (i) = free_ent++; /* code -> hashtable */
556			HashTabOf (i) = fcode;
557			} else
558			cl_block();
559			}
560			/*
561			* Put out the final code.
562			*/
563			output( (code_int)ent );
564			out_count++;
565			output( (code_int) EOFCode );
566			return;
567			}
568
569			/*****************************************************************
570			* TAG( output )
571			*
572			* Output the given code.
573			* Inputs:
574			* code: A n_bits-bit integer. If == -1, then EOF. This assumes
575			* that n_bits =< (long)wordsize - 1.
576			* Outputs:
577			* Outputs code to the file.
578			* Assumptions:
579			* Chars are 8 bits long.
580			* Algorithm:
581			* Maintain a CBITS character long buffer (so that 8 codes will
582			* fit in it exactly). Use the VAX insv instruction to insert each
583			* code in turn. When the buffer fills up empty it and start over.
584			*/
585
586			unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
587			0x001F, 0x003F, 0x007F, 0x00FF,
588			0x01FF, 0x03FF, 0x07FF, 0x0FFF,
589			0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
590
591			output( code )
592			code_int code;
593			{
594			cur_accum &= masks[ cur_bits ];
595			if( cur_bits > 0 )
596			cur_accum \|= ((long)code << cur_bits);
597			else
598			cur_accum = code;
599			cur_bits += n_bits;
600			while( cur_bits >= 8 ) {
601			char_out( (unsigned int)(cur_accum & 0xff) );
602			cur_accum >>= 8;
603			cur_bits -= 8;
604			}
605
606			/*
607			* If the next entry is going to be too big for the code size,
608			* then increase it, if possible.
609			*/
610			if ( free_ent > maxcode \|\| clear_flg ) {
611			if( clear_flg ) {
612			maxcode = MAXCODE (n_bits = g_init_bits);
613			clear_flg = 0;
614			} else {
615			n_bits++;
616			if ( n_bits == maxbits )
617			maxcode = maxmaxcode;
618			else
619			maxcode = MAXCODE(n_bits);
620			}
621			}
622			if( code == EOFCode ) {
623			/*
624			* At EOF, write the rest of the buffer.
625			*/
626			while( cur_bits > 0 ) {
627			char_out( (unsigned int)(cur_accum & 0xff) );
628			cur_accum >>= 8;
629			cur_bits -= 8;
630			}
631			flush_char();
632			fflush( g_outfile );
633			if( ferror( g_outfile ) )
634			writeerr();
635			}
636			}
637
638			/*
639			* Clear out the hash table
640			*/
641			cl_block () /* table clear for block compress */
642			{
643			cl_hash ( (count_int) hsize );
644			free_ent = ClearCode + 2;
645			clear_flg = 1;
646			output( (code_int)ClearCode );
647			}
648
649			cl_hash(hsize) /* reset code table */
650			register count_int hsize;
651			{
652			register count_int *htab_p = htab+hsize;
653			register long i;
654			register long m1 = -1;
655
656			i = hsize - 16;
657			do { /* might use Sys V memset(3) here */
658			*(htab_p-16) = m1;
659			*(htab_p-15) = m1;
660			*(htab_p-14) = m1;
661			*(htab_p-13) = m1;
662			*(htab_p-12) = m1;
663			*(htab_p-11) = m1;
664			*(htab_p-10) = m1;
665			*(htab_p-9) = m1;
666			*(htab_p-8) = m1;
667			*(htab_p-7) = m1;
668			*(htab_p-6) = m1;
669			*(htab_p-5) = m1;
670			*(htab_p-4) = m1;
671			*(htab_p-3) = m1;
672			*(htab_p-2) = m1;
673			*(htab_p-1) = m1;
674			htab_p -= 16;
675			} while ((i -= 16) >= 0);
676			for ( i += 16; i > 0; i-- )
677			*--htab_p = m1;
678			}
679
680			writeerr()
681			{
682			printf( "error writing output file\n" );
683			exit(1);
684			}
685
686			/******************************************************************************
687			*
688			* GIF Specific routines
689			*
690			******************************************************************************/
691
692			/*
693			* Number of characters so far in this 'packet'
694			*/
695			int a_count;
696
697			/*
698			* Set up the 'byte output' routine
699			*/
700			char_init()
701			{
702			a_count = 0;
703			}
704
705			/*
706			* Define the storage for the packet accumulator
707			*/
708			char accum[256];
709
710			/*
711			* Add a character to the end of the current packet, and if it is 254
712			* characters, flush the packet to disk.
713			*/
714			char_out( c )
715			int c;
716			{
717			accum[ a_count++ ] = c;
718			if( a_count >= 254 )
719			flush_char();
720			}
721
722			/*
723			* Flush the packet to disk, and reset the accumulator
724			*/
725			flush_char()
726			{
727			if( a_count > 0 ) {
728			fputc( a_count, g_outfile );
729			fwrite( accum, 1, a_count, g_outfile );
730			a_count = 0;
731			}
732			}
733
734			static float curgamma;
735			static short gamtab[256];
736
737			gammawarp(sbuf,gam,n)
738			short *sbuf;
739			float gam;
740			int n;
741			{
742			int i;
743			float f;
744
745			if(gam!=curgamma) {
746			for(i=0; i<256; i++)
747			gamtab[i] = 255*pow(i/255.0,gam)+0.5;
748			curgamma = gam;
749			}
750			while(n--) {
751			sbuf = gamtab[sbuf];
752			sbuf++;
753			}
754			}