gd.c

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		}
	} else {
		if (old == color) {
			/* Nothing to be done */
			return;
		}
	}
	/* Seek left */
	leftLimit = (-1);
	for (i = x; (i >= 0); i--) {
		if (gdImageGetPixel(im, i, y) != old) {
			break;
		}
		gdImageSetPixel(im, i, y, color);
		leftLimit = i;
	}
	if (leftLimit == (-1)) {
		return;
	}
	/* Seek right */
	rightLimit = x;
	for (i = (x+1); (i < im->sx); i++) {	
		if (gdImageGetPixel(im, i, y) != old) {
			break;
		}
		gdImageSetPixel(im, i, y, color);
		rightLimit = i;
	}
	/* Look at lines above and below and start paints */
	/* Above */
	if (y > 0) {
		lastBorder = 1;
		for (i = leftLimit; (i <= rightLimit); i++) {
			int c;
			c = gdImageGetPixel(im, i, y-1);
			if (lastBorder) {
				if (c == old) {	
					gdImageFill(im, i, y-1, color);		
					lastBorder = 0;
				}
			} else if (c != old) {
				lastBorder = 1;
			}
		}
	}
	/* Below */
	if (y < ((im->sy) - 1)) {
		lastBorder = 1;
		for (i = leftLimit; (i <= rightLimit); i++) {
			int c;
			c = gdImageGetPixel(im, i, y+1);
			if (lastBorder) {
				if (c == old) {
					gdImageFill(im, i, y+1, color);		
					lastBorder = 0;
				}
			} else if (c != old) {
				lastBorder = 1;
			}
		}
	}
}
	
#ifdef TEST_CODE
void gdImageDump(gdImagePtr im)
{
	int i, j;
	for (i=0; (i < im->sy); i++) {
		for (j=0; (j < im->sx); j++) {
			printf("%d", im->pixels[j][i]);
		}
		printf("\n");
	}
}
#endif

/* Code drawn from ppmtogif.c, from the pbmplus package
**
** Based on GIFENCOD by David Rowley <[e-mail]>. A
** Lempel-Zim compression based on "compress".
**
** Modified by Marcel Wijkstra <[e-mail]>
**
** 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.
*/

/*
 * a code_int must be able to hold 2**GIFBITS values of type int, and also -1
 */
typedef int             code_int;

#ifdef SIGNED_COMPARE_SLOW
typedef unsigned long int count_int;
typedef unsigned short int count_short;
#else /*SIGNED_COMPARE_SLOW*/
typedef long int          count_int;
#endif /*SIGNED_COMPARE_SLOW*/

static int colorstobpp(int colors);
static void BumpPixel (void);
static int GIFNextPixel (gdImagePtr im);
static void GIFEncode (FILE *fp, int GWidth, int GHeight, int GInterlace, int Background, int Transparent, int BitsPerPixel, int *Red, int *Green, int *Blue, gdImagePtr im);
static void Putword (int w, FILE *fp);
static void compress (int init_bits, FILE *outfile, gdImagePtr im);
static void output (code_int code);
static void cl_block (void);
static void cl_hash (register count_int hsize);
static void char_init (void);
static void char_out (int c);
static void flush_char (void);
/* Allows for reuse */
static void init_statics(void);

void gdImageGif(gdImagePtr im, FILE *out)
{
	int interlace, transparent, BitsPerPixel;
	interlace = im->interlace;
	transparent = im->transparent;

	BitsPerPixel = colorstobpp(im->colorsTotal);
	/* Clear any old values in statics strewn through the GIF code */
	init_statics();
	/* All set, let's do it. */
	GIFEncode(
		out, im->sx, im->sy, interlace, 0, transparent, BitsPerPixel,
		im->red, im->green, im->blue, im);
}

static int
colorstobpp(int colors)
{
    int bpp = 0;

    if ( colors <= 2 )
        bpp = 1;
    else if ( colors <= 4 )
        bpp = 2;
    else if ( colors <= 8 )
        bpp = 3;
    else if ( colors <= 16 )
        bpp = 4;
    else if ( colors <= 32 )
        bpp = 5;
    else if ( colors <= 64 )
        bpp = 6;
    else if ( colors <= 128 )
        bpp = 7;
    else if ( colors <= 256 )
        bpp = 8;
    return bpp;
    }

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

#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
 */
static void
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
 */
static int
GIFNextPixel(gdImagePtr im)
{
        int r;

        if( CountDown == 0 )
                return EOF;

        --CountDown;

        r = gdImageGetPixel(im, curx, cury);

        BumpPixel();

        return r;
}

/* public */

static void
GIFEncode(FILE *fp, int GWidth, int GHeight, int GInterlace, int Background, int Transparent, int BitsPerPixel, int *Red, int *Green, int *Blue, gdImagePtr im)
{
        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( (unsigned char) 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, im );

        /*
         * Write out a Zero-length packet (to end the series)
         */
        fputc( 0, fp );

        /*
         * Write the GIF file terminator
         */
        fputc( ';', 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 ([e-mail])
 *
 ***************************************************************************/

/*
 * General DEFINEs
 */

#define GIFBITS    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 = GIFBITS;                /* user settable max # bits/code */
static code_int maxcode;                  /* maximum code, given n_bits */
static code_int maxmaxcode = (code_int)1 << GIFBITS; /* 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**GIFBITS 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<<GIFBITS))

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;

static void
compress(int init_bits, FILE *outfile, gdImagePtr im)
{
    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( im );

    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( im )) != (unsigned) EOF ) {
#else /*SIGNED_COMPARE_SLOW*/
    while ( (c = GIFNextPixel( im )) != 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) = 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 GIFBITS character long buffer (so that 8 codes will