/*
 * Apply median cut on an image.
 *
 * median [-c n] [-f] input output
 *     -c n		- set colortable size.  Default is 256.
 *     -f		- use Floyd-Steinberg dithering.
 *     -lzw		- compress output with LZW
 *     -none		- use no compression on output
 *     -picio		- use picio compression on output
 *     -packbits	- use packbits compression on output
 *     -rowsperstrip n	- create output with n rows/strip of data
 * (by default the compression scheme and rows/strip are taken
 *  from the input file)
 *
 * Notes:
 *
 * [1] Floyd-Steinberg dither:
 *  I should point out that the actual fractions we used were, assuming
 *  you are at X, moving left to right:
 *
 *		    X     7/16
 *	     3/16   5/16  1/16    
 *
 *  Note that the error goes to four neighbors, not three.  I think this
 *  will probably do better (at least for black and white) than the
 *  3/8-3/8-1/4 distribution, at the cost of greater processing.  I have
 *  seen the 3/8-3/8-1/4 distribution described as "our" algorithm before,
 *  but I have no idea who the credit really belongs to.

 *  Also, I should add that if you do zig-zag scanning (see my immediately
 *  previous message), it is sufficient (but not quite as good) to send
 *  half the error one pixel ahead (e.g. to the right on lines you scan
 *  left to right), and half one pixel straight down.  Again, this is for
 *  black and white;  I've not tried it with color.
 *  -- 
 *					    Lou Steinberg
 *
 * [2] Color Image Quantization for Frame Buffer Display, Paul Heckbert,
 *	Siggraph '82 proceedings, pp. 297-307
 */
#include <stdio.h>
#include <sys/types.h>
#include <rasterfile.h>

#define	MAX_CMAP_SIZE	256
#define	howmany(x, y)	(((x)+((y)-1))/(y))
#define	streq(a,b)	(strcmp(a,b) == 0)

#define	COLOR_DEPTH	8
#define	MAX_COLOR	256

#define	B_DEPTH		4		/* # bits/pixel to use */
#define	B_LEN		(1<<B_DEPTH)

#define	C_DEPTH		2
#define	C_LEN		(1<<C_DEPTH)	/* # cells/color to use */

#define	COLOR_SHIFT	(COLOR_DEPTH-B_DEPTH)
#define COMPRESSION_NONE 0
#define COMPRESSION_PACKBITS 1
#define COMPRESSION_LZW 2
#define COMPRESSION_PICIO 3


typedef	struct colorbox {
	struct	colorbox *next, *prev;
	int	rmin, rmax;
	int	gmin, gmax;
	int	bmin, bmax;
	int	total;
} Colorbox;

typedef struct {
	int	num_ents;
	int	entries[MAX_CMAP_SIZE][2];
} C_cell;

u_short	rm[MAX_CMAP_SIZE], gm[MAX_CMAP_SIZE], bm[MAX_CMAP_SIZE];
int	bytes_per_pixel;
long	num_colors, width, hieght, length;
int	histogram[B_LEN][B_LEN][B_LEN];
Colorbox *freeboxes;
Colorbox *usedboxes;
Colorbox *largest_box();
C_cell	**ColorCells;
FILE	*in, *out;

char	*usage = "usage: median [-c n] [-f] [-none] [-lzw] [-picio] [-packbits] [-rowsperstrip r] input output\n";

main(argc, argv)
	int argc;
	char **argv;
{
	struct rasterfile header;
	int i, j, dither = 0;
	long chunk;
	char *ifile_name = NULL, *ofile_name = NULL, color;
	Colorbox *box_list, *ptr;
	u_short rowsperstrip = 128, compression = -1, shortv;
	u_short bitspersample, samplesperpixel, photometric;
	float floatv;

	num_colors = MAX_CMAP_SIZE;
	for (argc--, argv++; argc > 0 && argv[0][0] == '-'; argc--, argv++) {
		if (streq(argv[0], "-f")) {
			dither = 1;
			continue;
		}
		if (streq(argv[0], "-c")) {
			argc--, argv++;
			if (argc < 1) {
				fprintf(stderr, "-c: missing colormap size\n%s",
				    usage);
				exit(1);
			}
			num_colors = atoi(argv[0]);
			if (num_colors > MAX_CMAP_SIZE) {
				fprintf(stderr,
				   "-c: colormap too big, max %d\n%s",
				   MAX_CMAP_SIZE, usage);
				exit(1);
			}
			continue;
		}
		if (streq(argv[0], "-none")) {
			compression = COMPRESSION_NONE;
			continue;
		}
		if (streq(argv[0], "-packbits")) {
			compression = COMPRESSION_PACKBITS;
			continue;
		}
		if (streq(argv[0], "-lzw")) {
			compression = COMPRESSION_LZW;
			continue;
		}
		if (streq(argv[0], "-picio")) {
			compression = COMPRESSION_PICIO;
			continue;
		}
		if (streq(argv[0], "-rowsperstrip")) {
			argc--, argv++;
			rowsperstrip = atoi(argv[0]);
			continue;
		}
		fprintf(stderr, "%s: unknown option\n%s", argv[0], usage);
		exit(1);
	}
	if (argc < 2) {
		fprintf(stderr, "%s", usage);
		exit(-1);
	}
	in = fopen(argv[0], "r");
	if (in == NULL)
		exit(-1);

	fread(&width, 4, 1, in); /* Get size of picture */
	fread(&hieght, 4, 1, in);
	length = hieght;

	/*
	 * STEP 1:  create empty boxes
	 */
	usedboxes = NULL;
	box_list = freeboxes = (Colorbox *)malloc(num_colors*sizeof (Colorbox));
	freeboxes[0].next = &freeboxes[1];
	freeboxes[0].prev = NULL;
	for (i = 1; i < num_colors-1; ++i) {
		freeboxes[i].next = &freeboxes[i+1];
		freeboxes[i].prev = &freeboxes[i-1];
	}
	freeboxes[num_colors-1].next = NULL;
	freeboxes[num_colors-1].prev = &freeboxes[num_colors-2];

	/*
	 * STEP 2: get histogram, initialize first box
	 */
	ptr = freeboxes;
	freeboxes = ptr->next;
	if (freeboxes)
		freeboxes->prev = NULL;
	ptr->next = usedboxes;
	usedboxes = ptr;
	if (ptr->next)
		ptr->next->prev = ptr;
	get_histogram(in, ptr);

	/*
	 * STEP 3: continually subdivide boxes until no more free
	 * boxes remain or until all colors assigned.
	 */
	while (freeboxes != NULL) {
		ptr = largest_box();
		if (ptr != NULL)
			splitbox(ptr);
		else
			freeboxes = NULL;
	}

	/*
	 * STEP 4: assign colors to all boxes
	 */
	for (i = 0, ptr = usedboxes; ptr != NULL; ++i, ptr = ptr->next) {
		rm[i] = ((ptr->rmin + ptr->rmax) << COLOR_SHIFT) / 2;
		gm[i] = ((ptr->gmin + ptr->gmax) << COLOR_SHIFT) / 2;
		bm[i] = ((ptr->bmin + ptr->bmax) << COLOR_SHIFT) / 2;
	}

	fprintf(stderr,"Number of colors used %d\n", i);

	/* We're done with the boxes now */
	free(box_list);
	box_list = freeboxes = usedboxes = NULL;

	/*
	 * STEP 5: scan histogram and map all values to closest color
	 */
	/* 5a: create cell list as described in Heckbert[2] */
	ColorCells = (C_cell **)calloc(C_LEN*C_LEN*C_LEN, sizeof (C_cell *));
	/* 5b: create mapping from truncated pixel space to color
	   table entries */
	map_colortable();

	/*
	 * STEP 6: scan image, match input values to table entries
	 */
	out = fopen(argv[1], "w");
	if (out == NULL)
		exit(-2);

	header.ras_magic= 0x59a66a95;
	header.ras_width= width;
  	header.ras_height= hieght;
  	header.ras_depth= 8;
	header.ras_length= width * hieght;
  	header.ras_type= RT_STANDARD;
  	header.ras_maptype= RMT_EQUAL_RGB;
  	header.ras_maplength= 3*256;

/* Write out the rasterfile header to the ouput */

	fwrite(&header, sizeof(header), 1, out);

/* Write the colormap to the ouput */

	for(i=0;i<256;i++) {
	  color = (char)rm[i];
	  fwrite(&color, 1, 1, out);
	}

	for(i=0;i<256;i++) {
	  color = (char)gm[i];
	  fwrite(&color, 1, 1, out);
	}

	for(i=0;i<256;i++) {
	  color = (char)bm[i];
	  fwrite(&color, 1, 1, out);
	}

	rewind(in);		/* rewind input file XXX */

	fread(&chunk, 4, 1, in);
	fread(&chunk, 4, 1, in);
	if (dither)
		quant_fsdither(in, out);
	else
		quant(in, out);
	(void) fclose(out);

}

static
get_histogram(in, box)
	FILE *in;
	register Colorbox *box;
{
	register u_char *inptr;
	register int red, green, blue, j, i;
	u_char *inline;

	i = 24 * width;
	inline = (u_char *)malloc(howmany(i, 8));
	if (inline == NULL) {
		fprintf(stderr, "No space for scanline buffer\n");
		exit(-1);
	}
	box->rmin = box->gmin = box->bmin = 999;
	box->rmax = box->gmax = box->bmax = -1;
	box->total = width * length;

	{ register int *ptr = &histogram[0][0][0];
	  for (i = B_LEN*B_LEN*B_LEN; --i >= 0;)
		*ptr++ = 0;
	}
	for (i = length; i-- > 0;) {
		if (fread(inline, width*3, 1, in) <= 0)
			break;
		inptr = inline;
		for (j = width; j-- > 0;) {
			red = *inptr++ >> COLOR_SHIFT;
			green = *inptr++ >> COLOR_SHIFT;
			blue = *inptr++ >> COLOR_SHIFT; 
			if (red < box->rmin)
				box->rmin = red;
		        if (red > box->rmax)
				box->rmax = red;
		        if (green < box->gmin)
				box->gmin = green;
		        if (green > box->gmax)
				box->gmax = green;
		        if (blue < box->bmin)
				box->bmin = blue;
		        if (blue > box->bmax)
				box->bmax = blue;
		        histogram[red][green][blue]++;
		}
	}
	free(inline);
}

static Colorbox *
largest_box()
{
	register Colorbox *p, *b;
	register int size;

	b = NULL;
	size = -1;
	for (p = usedboxes; p != NULL; p = p->next)
		if ((p->rmax > p->rmin || p->gmax > p->gmin ||
		    p->bmax > p->bmin) &&  p->total > size)
		        size = (b = p)->total;
	return (b);
}

static
splitbox(ptr)
	register Colorbox *ptr;
{
	int		hist2[B_LEN];
	int		first, last;
	register Colorbox	*new;
	register int	*iptr, *histp;
	register int	i, j;
	register int	ir,ig,ib;
	register int sum, sum1, sum2;
	int		total;
	enum { RED, GREEN, BLUE } axis;

	/*
	 * See which axis is the largest, do a histogram along that
	 * axis.  Split at median point.  Contract both new boxes to
	 * fit points and return
	 */
	i = ptr->rmax - ptr->rmin;
	if (i >= ptr->gmax - ptr->gmin  && i >= ptr->bmax - ptr->bmin)
		axis = RED;
	else if (ptr->gmax - ptr->gmin >= ptr->bmax - ptr->bmin)
		axis = GREEN;
	else
		axis = BLUE;
	/* get histogram along longest axis */
	switch (axis) {
	case RED:
		histp = &hist2[ptr->rmin];
	        for (ir = ptr->rmin; ir <= ptr->rmax; ++ir) {
			*histp = 0;
			for (ig = ptr->gmin; ig <= ptr->gmax; ++ig) {
				iptr = &histogram[ir][ig][ptr->bmin];
				for (ib = ptr->bmin; ib <= ptr->bmax; ++ib)
					*histp += *iptr++;
			}
			histp++;
	        }
	        first = ptr->rmin;
		last = ptr->rmax;
	        break;
	case GREEN:
	        histp = &hist2[ptr->gmin];
	        for (ig = ptr->gmin; ig <= ptr->gmax; ++ig) {
			*histp = 0;
			for (ir = ptr->rmin; ir <= ptr->rmax; ++ir) {
				iptr = &histogram[ir][ig][ptr->bmin];
				for (ib = ptr->bmin; ib <= ptr->bmax; ++ib)
					*histp += *iptr++;
			}
			histp++;
	        }
	        first = ptr->gmin;
		last = ptr->gmax;
	        break;
	case BLUE:
	        histp = &hist2[ptr->bmin];
	        for (ib = ptr->bmin; ib <= ptr->bmax; ++ib) {
			*histp = 0;
			for (ir = ptr->rmin; ir <= ptr->rmax; ++ir) {
				iptr = &histogram[ir][ptr->gmin][ib];
				for (ig = ptr->gmin; ig <= ptr->gmax; ++ig) {
					*histp += *iptr;
					iptr += B_LEN;
				}
			}
			histp++;
	        }
	        first = ptr->bmin;
		last = ptr->bmax;
	        break;
	}
	/* find median point */
	histp = &hist2[first];
	sum2 = ptr->total / 2;
	histp = &hist2[first];
	sum = 0;
	for (i = first; i <= last && (sum += *histp++) < sum2; ++i)
		;
	if (i == first)
		i++;

	/* Create new box, re-allocate points */
	new = freeboxes;
	freeboxes = new->next;
	if (freeboxes)
		freeboxes->prev = NULL;
	if (usedboxes)
		usedboxes->prev = new;
	new->next = usedboxes;
	usedboxes = new;

	total = ptr->total;
	histp = &hist2[first];
	for (sum1 = 0, j = first; j < i; j++)
		sum1 += *histp++;
	for (sum2 = 0, j = i; j <= last; j++)
	    sum2 += *histp++;
	new->total = sum1;
	ptr->total = sum2;

	new->rmin = ptr->rmin;
	new->rmax = ptr->rmax;
	new->gmin = ptr->gmin;
	new->gmax = ptr->gmax;
	new->bmin = ptr->bmin;
	new->bmax = ptr->bmax;
	switch (axis) {
	case RED:
		new->rmax = i-1;
	        ptr->rmin = i;
	        break;
	case GREEN:
	        new->gmax = i-1;
	        ptr->gmin = i;
	        break;
	case BLUE:
	        new->bmax = i-1;
	        ptr->bmin = i;
	        break;
	}
	shrinkbox(new);
	shrinkbox(ptr);
}

static
shrinkbox(box)
	register Colorbox *box;
{
	register int *histp, ir, ig, ib;

	if (box->rmax > box->rmin) {
		for (ir = box->rmin; ir <= box->rmax; ++ir)
			for (ig = box->gmin; ig <= box->gmax; ++ig) {
				histp = &histogram[ir][ig][box->bmin];
			        for (ib = box->bmin; ib <= box->bmax; ++ib)
					if (*histp++ != 0) {
						box->rmin = ir;
						goto have_rmin;
					}
			}
	have_rmin:
		if (box->rmax > box->rmin)
			for (ir = box->rmax; ir >= box->rmin; --ir)
				for (ig = box->gmin; ig <= box->gmax; ++ig) {
					histp = &histogram[ir][ig][box->bmin];
					ib = box->bmin;
					for (; ib <= box->bmax; ++ib)
						if (*histp++ != 0) {
							box->rmax = ir;
							goto have_rmax;
						}
			        }
	}
have_rmax:
	if (box->gmax > box->gmin) {
		for (ig = box->gmin; ig <= box->gmax; ++ig)
			for (ir = box->rmin; ir <= box->rmax; ++ir) {
				histp = &histogram[ir][ig][box->bmin];
			        for (ib = box->bmin; ib <= box->bmax; ++ib)
				if (*histp++ != 0) {
					box->gmin = ig;
					goto have_gmin;
				}
			}
	have_gmin:
		if (box->gmax > box->gmin)
			for (ig = box->gmax; ig >= box->gmin; --ig)
				for (ir = box->rmin; ir <= box->rmax; ++ir) {
					histp = &histogram[ir][ig][box->bmin];
					ib = box->bmin;
					for (; ib <= box->bmax; ++ib)
						if (*histp++ != 0) {
							box->gmax = ig;
							goto have_gmax;
						}
			        }
	}
have_gmax:
	if (box->bmax > box->bmin) {
		for (ib = box->bmin; ib <= box->bmax; ++ib)
			for (ir = box->rmin; ir <= box->rmax; ++ir) {
				histp = &histogram[ir][box->gmin][ib];
			        for (ig = box->gmin; ig <= box->gmax; ++ig) {
					if (*histp != 0) {
						box->bmin = ib;
						goto have_bmin;
					}
					histp += B_LEN;
			        }
		        }
	have_bmin:
		if (box->bmax > box->bmin)
			for (ib = box->bmax; ib >= box->bmin; --ib)
				for (ir = box->rmin; ir <= box->rmax; ++ir) {
					histp = &histogram[ir][box->gmin][ib];
					ig = box->gmin;
					for (; ig <= box->gmax; ++ig) {
						if (*histp != 0) {
							box->bmax = ib;
							goto have_bmax;
						}
						histp += B_LEN;
					}
			        }
	}
have_bmax:
	;
}

static C_cell *
create_colorcell(red, green, blue)
	int red, green, blue;
{
	register int ir, ig, ib, i;
	register C_cell *ptr;
	int mindist, next_n;
	register int tmp, dist, n;

	ir = red >> (COLOR_DEPTH-C_DEPTH);
	ig = green >> (COLOR_DEPTH-C_DEPTH);
	ib = blue >> (COLOR_DEPTH-C_DEPTH);
	ptr = (C_cell *)malloc(sizeof (C_cell));
	*(ColorCells + ir*C_LEN*C_LEN + ig*C_LEN + ib) = ptr;
	ptr->num_ents = 0;

	/*
	 * Step 1: find all colors inside this cell, while we're at
	 *	   it, find distance of centermost point to furthest corner
	 */
	mindist = 99999999;
	for (i = 0; i < num_colors; ++i) {
		if (rm[i]>>(COLOR_DEPTH-C_DEPTH) != ir  ||
		    gm[i]>>(COLOR_DEPTH-C_DEPTH) != ig  ||
		    bm[i]>>(COLOR_DEPTH-C_DEPTH) != ib)
			continue;
		ptr->entries[ptr->num_ents][0] = i;
		ptr->entries[ptr->num_ents][1] = 0;
		++ptr->num_ents;
	        tmp = rm[i] - red;
	        if (tmp < (MAX_COLOR/C_LEN/2))
			tmp = MAX_COLOR/C_LEN-1 - tmp;
	        dist = tmp*tmp;
	        tmp = gm[i] - green;
	        if (tmp < (MAX_COLOR/C_LEN/2))
			tmp = MAX_COLOR/C_LEN-1 - tmp;
	        dist += tmp*tmp;
	        tmp = bm[i] - blue;
	        if (tmp < (MAX_COLOR/C_LEN/2))
			tmp = MAX_COLOR/C_LEN-1 - tmp;
	        dist += tmp*tmp;
	        if (dist < mindist)
			mindist = dist;
	}

	/*
	 * Step 3: find all points within that distance to cell.
	 */
	for (i = 0; i < num_colors; ++i) {
		if (rm[i] >> (COLOR_DEPTH-C_DEPTH) == ir  &&
		    gm[i] >> (COLOR_DEPTH-C_DEPTH) == ig  &&
		    bm[i] >> (COLOR_DEPTH-C_DEPTH) == ib)
			continue;
		dist = 0;
	        if ((tmp = red - rm[i]) > 0 ||
		    (tmp = rm[i] - (red + MAX_COLOR/C_LEN-1)) > 0 )
			dist += tmp*tmp;
	        if ((tmp = green - gm[i]) > 0 ||
		    (tmp = gm[i] - (green + MAX_COLOR/C_LEN-1)) > 0 )
			dist += tmp*tmp;
	        if ((tmp = blue - bm[i]) > 0 ||
		    (tmp = bm[i] - (blue + MAX_COLOR/C_LEN-1)) > 0 )
			dist += tmp*tmp;
	        if (dist < mindist) {
			ptr->entries[ptr->num_ents][0] = i;
			ptr->entries[ptr->num_ents][1] = dist;
			++ptr->num_ents;
	        }
	}

	/*
	 * Sort color cells by distance, use cheap exchange sort
	 */
	for (n = ptr->num_ents - 1; n > 0; n = next_n) {
		next_n = 0;
		for (i = 0; i < n; ++i)
			if (ptr->entries[i][1] > ptr->entries[i+1][1]) {
				tmp = ptr->entries[i][0];
				ptr->entries[i][0] = ptr->entries[i+1][0];
				ptr->entries[i+1][0] = tmp;
				tmp = ptr->entries[i][1];
				ptr->entries[i][1] = ptr->entries[i+1][1];
				ptr->entries[i+1][1] = tmp;
				next_n = i;
		        }
	}
	return (ptr);
}

static
map_colortable()
{
	register int *histp = &histogram[0][0][0];
	register C_cell *cell;
	register int j, tmp, d2, dist;
	int ir, ig, ib, i;

	for (ir = 0; ir < B_LEN; ++ir)
		for (ig = 0; ig < B_LEN; ++ig)
			for (ib = 0; ib < B_LEN; ++ib, histp++) {
				if (*histp == 0) {
					*histp = -1;
					continue;
				}
				cell = *(ColorCells +
				    (((ir>>(B_DEPTH-C_DEPTH)) << C_DEPTH*2) +
				    ((ig>>(B_DEPTH-C_DEPTH)) << C_DEPTH) +
				    (ib>>(B_DEPTH-C_DEPTH))));
				if (cell == NULL )
					cell = create_colorcell(
					    ir << COLOR_SHIFT,
					    ig << COLOR_SHIFT,
					    ib << COLOR_SHIFT);
				dist = 9999999;
				for (i = 0; i < cell->num_ents &&
				    dist > cell->entries[i][1]; ++i) {
					j = cell->entries[i][0];
					d2 = rm[j] - (ir << COLOR_SHIFT);
					d2 *= d2;
					tmp = gm[j] - (ig << COLOR_SHIFT);
					d2 += tmp*tmp;
					tmp = bm[j] - (ib << COLOR_SHIFT);
					d2 += tmp*tmp;
					if (d2 < dist) {
						dist = d2;
						*histp = j;
					}
				}
			}
}

/*
 * straight quantization.  Each pixel is mapped to the colors
 * closest to it.  Color values are rounded to the nearest color
 * table entry.
 */
static
quant(in, out)
	FILE *in, *out;
{
	u_char	*outline, *inline;
	register u_char	*outptr, *inptr;
	register int i, j, red, green, blue;

	i = 24 * width;
	inline = (u_char *)malloc(howmany(i, 8));
	outline = (u_char *)malloc(width);
	for (i = 0; i < length; i++) {
		if (fread(inline, 3*width, 1, in) <= 0)
			break;
		inptr = inline;
		outptr = outline;
		for (j = 0; j < width; j++) {
			red = *inptr++ >> COLOR_SHIFT;
			green = *inptr++ >> COLOR_SHIFT;
			blue = *inptr++ >> COLOR_SHIFT;
			*outptr++ = histogram[red][green][blue];
		}
		if (fwrite(outline, width, 1, out) <= 0)
			break;
	}
	free(inline);
	free(outline);
}

static
quant_fsdither(in, out)
	FILE *in, *out;
{
	u_char *outline, *inline, *inptr;
	short *thisline, *nextline, *tmpptr;
	register u_char	*outptr;
	register short *thisptr, *nextptr;
	register int i, j, tmp;
	int imax, jmax, lastline, lastpixel;

	imax = length - 1;
	jmax = width - 1;
	i = 12 * width;
	inline = (u_char *)malloc(howmany(i, 8));
	thisline = (short *)malloc(width * 3 * sizeof (short));
	nextline = (short *)malloc(width * 3 * sizeof (short));
	outline = (unsigned char *) malloc(width);

	/*
	 * Get first line
	 */
	if (fread(inline, 3*width, 1, in) <= 0)
		return;
	inptr = inline;
	nextptr = nextline;
	for (j = 0; j < width; ++j) {
		*nextptr++ = *inptr++;
		*nextptr++ = *inptr++;
		*nextptr++ = *inptr++;
	}
	for (i = 0; i < length; ++i) {
		tmpptr = thisline;
		thisline = nextline;
		nextline = tmpptr;
		lastline = (i == imax);
		if (fread(inline, 3*width, 1, in) <= 0)
			break;
		inptr = inline;
		nextptr = nextline;
		for (j = 0; j < width; ++j) {
			*nextptr++ = *inptr++;
			*nextptr++ = *inptr++;
			*nextptr++ = *inptr++;
		}
		thisptr = thisline;
		nextptr = nextline;
		outptr = outline;
		for (j = 0; j < width; ++j) {
			int red, green, blue;
			register int oval, r2, g2, b2;

			lastpixel = (j == jmax);
			b2 = *thisptr++;
			g2 = *thisptr++;
			r2 = *thisptr++;
			if (r2 < 0)
				r2 = 0;
			else if (r2 >= MAX_COLOR)
				r2 = MAX_COLOR-1;
			if (g2 < 0)
				g2 = 0;
			else if (g2 >= MAX_COLOR)
				g2 = MAX_COLOR-1;
			if (b2 < 0)
				b2 = 0;
			else if (b2 >= MAX_COLOR)
				b2 = MAX_COLOR-1;
			red = r2;
			green = g2;
			blue = b2;
			r2 >>= COLOR_SHIFT;
			g2 >>= COLOR_SHIFT;
			b2 >>= COLOR_SHIFT;
			oval = histogram[r2][g2][b2];
			if (oval == -1) {
				int ci;
				register int cj, tmp, d2, dist;
				register C_cell	*cell;

				cell = *(ColorCells +
				    (((r2>>(B_DEPTH-C_DEPTH)) << C_DEPTH*2) +
				    ((g2>>(B_DEPTH-C_DEPTH)) << C_DEPTH ) +
				    (b2>>(B_DEPTH-C_DEPTH))));
				if (cell == NULL )
					cell = create_colorcell(red,
					    green, blue);
				dist = 9999999;
				for (ci = 0; ci < cell->num_ents && dist > cell->entries[ci][1]; ++ci) {
					cj = cell->entries[ci][0];
					d2 = (rm[cj] >> COLOR_SHIFT) - r2;
					d2 *= d2;
					tmp = (gm[cj] >> COLOR_SHIFT) - g2;
					d2 += tmp*tmp;
					tmp = (bm[cj] >> COLOR_SHIFT) - b2;
					d2 += tmp*tmp;
					if (d2 < dist) {
						dist = d2;
						oval = cj;
					}
				}
				histogram[r2][g2][b2] = oval;
			}
			*outptr++ = oval;
			red -= rm[oval];
			green -= gm[oval];
			blue -= bm[oval];
			if (!lastpixel) {
				thisptr[0] += blue * 7 / 16;
				thisptr[1] += green * 7 / 16;
				thisptr[2] += red * 7 / 16;
			}
			if (!lastline) {
				if (j != 0) {
					nextptr[-3] += blue * 3 / 16;
					nextptr[-2] += green * 3 / 16;
					nextptr[-1] += red * 3 / 16;
				}
				nextptr[0] += blue * 5 / 16;
				nextptr[1] += green * 5 / 16;
				nextptr[2] += red * 5 / 16;
				if (!lastpixel) {
					nextptr[3] += blue / 16;
				        nextptr[4] += green / 16;
				        nextptr[5] += red / 16;
				}
				nextptr += 3;
			}
		}
		if (fwrite(outline, width, 1, out) < 0)
			break;
	}
	free(inline);
	free(thisline);
	free(nextline);
	free(outline);
}