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Comparing ray/src/px/clrtab.c (file contents):
Revision 2.1 by greg, Mon Oct 12 12:58:39 1992 UTC vs.
Revision 2.7 by greg, Thu Jun 10 15:45:18 1993 UTC

#	Line 1 | Line 1
1	<	/* Copyright (c) 1992 Regents of the University of California */
1	>	/* Copyright (c) 1993 Regents of the University of California */
2
3		#ifndef lint
4		static char SCCSid[] = "$SunId$ LBL";
#	Line 31 | Line 31 | static unsigned        histo[NRED][NGRN][NBLU];
31		static int      CLRCUBE[3][2] = {0,NRED,0,NGRN,0,NBLU};
32		/* maximum propagated error during dithering */
33		#define MAXERR          20
34	+	/* define CLOSEST to get closest colors */
35	+	#ifndef CLOSEST
36	+	#ifdef SPEED
37	+	#if  SPEED > 8
38	+	#define CLOSEST         1       /* this step takes a little longer */
39	+	#endif
40	+	#endif
41	+	#endif
42
43
44		new_histo()             /* clear our histogram */
#	Line 66 | Line 74 | int    ncolors;
74		ncolors = 256;
75		/* partition color space */
76		cut(CLRCUBE, 0, ncolors);
77	+	#ifdef CLOSEST
78	+	closest(ncolors);       /* ensure colors picked are closest */
79	+	#endif
80		/* return new color table size */
81		return(ncolors);
82		}
#	Line 170 | Line 181 | register int   box[3][2];
181		#define c0      r
182		register int    r, g, b;
183		int     pri;
184	<	int     t[HMAX], med;
184	>	long    t[HMAX], med;
185		/* find dominant axis */
186		pri = RED;
187		if (box[GRN][1]-box[GRN][0] > box[pri][1]-box[pri][0])
#	Line 226 | Line 237 | mktabent(p, box)       /* compute average color for box and
237		int     p;
238		register int    box[3][2];
239		{
240	<	long    sum[3];
241	<	int     r, g, n;
242	<	register int    b, c;
240	>	unsigned long   sum[3];
241	>	unsigned        r, g;
242	>	unsigned long   n;
243	>	register unsigned       b, c;
244		/* sum pixels in box */
245		n = 0;
246		sum[RED] = sum[GRN] = sum[BLU] = 0;
#	Line 243 | Line 255 | register int   box[3][2];
255		}
256		histo[r][g][b] = p;         /* assign pixel */
257		}
258	+	if (n >= (1L<<23)/HMAX) {               /* avoid overflow */
259	+	sum[RED] /= n;
260	+	sum[GRN] /= n;
261	+	sum[BLU] /= n;
262	+	n = 1;
263	+	}
264		if (n) {                                /* compute average */
265		clrtab[p][RED] = sum[RED]*256/NRED/n;
266		clrtab[p][GRN] = sum[GRN]*256/NGRN/n;
#	Line 253 | Line 271 | register int   box[3][2];
271		clrtab[p][BLU] = (box[BLU][0]+box[BLU][1])*256/NBLU/2;
272		}
273		}
274	+
275	+
276	+	#ifdef CLOSEST
277	+	#define NBSIZ           32
278	+	static
279	+	closest(n)                      /* make sure we have the closest colors */
280	+	int     n;
281	+	{
282	+	BYTE    *neigh[256];
283	+	register int    r, g, b;
284	+	#define i r
285	+	/* get space for neighbor lists */
286	+	for (i = 0; i < n; i++) {
287	+	if ((neigh[i] = (BYTE *)malloc(NBSIZ)) == NULL) {
288	+	while (i--)
289	+	free(neigh[i]);
290	+	return;                 /* ENOMEM -- abandon effort */
291	+	}
292	+	neigh[i][0] = i;                /* identity is terminator */
293	+	}
294	+	/* make neighbor lists */
295	+	for (r = 0; r < NRED; r++)
296	+	for (g = 0; g < NGRN; g++)
297	+	for (b = 0; b < NBLU; b++) {
298	+	if (r < NRED-1 && histo[r][g][b] != histo[r+1][g][b])
299	+	addneigh(neigh, histo[r][g][b], histo[r+1][g][b]);
300	+	if (g < NGRN-1 && histo[r][g][b] != histo[r][g+1][b])
301	+	addneigh(neigh, histo[r][g][b], histo[r][g+1][b]);
302	+	if (b < NBLU-1 && histo[r][g][b] != histo[r][g][b+1])
303	+	addneigh(neigh, histo[r][g][b], histo[r][g][b+1]);
304	+	}
305	+	/* assign closest values */
306	+	for (r = 0; r < NRED; r++)
307	+	for (g = 0; g < NGRN; g++)
308	+	for (b = 0; b < NBLU; b++)
309	+	setclosest(neigh, r, g, b);
310	+	/* free neighbor lists */
311	+	for (i = 0; i < n; i++)
312	+	free(neigh[i]);
313	+	#undef i
314	+	}
315	+
316	+
317	+	static
318	+	addneigh(nl, i, j)              /* i and j are neighbors; add them to list */
319	+	register BYTE   *nl[];
320	+	register int    i;
321	+	int     j;
322	+	{
323	+	int     nc;
324	+	char    *nnl;
325	+	register int    t;
326	+
327	+	for (nc = 0; nc < 2; nc++) {            /* do both neighbors */
328	+	for (t = 0; nl[i][t] != i; t++)
329	+	if (nl[i][t] == j)
330	+	break;          /* in list already */
331	+	if (nl[i][t] == i) {            /* add to list */
332	+	nl[i][t++] = j;
333	+	if (t % NBSIZ == 0) {   /* enlarge list */
334	+	if ((nnl = realloc(nl[i], t+NBSIZ)) == NULL)
335	+	t--;
336	+	else
337	+	nl[i] = (BYTE *)nnl;
338	+	}
339	+	nl[i][t] = i;           /* terminator */
340	+	}
341	+	t = i; i = j; j = t;            /* swap and do it again */
342	+	}
343	+	}
344	+
345	+
346	+	static unsigned
347	+	dist(col, r, g, b)              /* find distance from clrtab entry to r,g,b */
348	+	register BYTE   col[3];
349	+	int     r, g, b;
350	+	{
351	+	register int    tmp;
352	+	register unsigned       sum;
353	+
354	+	tmp = col[RED]*NRED/256 - r;
355	+	sum = tmp*tmp;
356	+	tmp = col[GRN]*NGRN/256 - g;
357	+	sum += tmp*tmp;
358	+	tmp = col[BLU]*NBLU/256 - b;
359	+	sum += tmp*tmp;
360	+	return(sum);
361	+	}
362	+
363	+
364	+	static
365	+	setclosest(nl, r, g, b)         /* find index closest to color and assign */
366	+	BYTE    *nl[];
367	+	int     r, g, b;
368	+	{
369	+	int     ident;
370	+	unsigned        min;
371	+	register unsigned       d;
372	+	register BYTE   *p;
373	+	/* get starting value */
374	+	min = dist(clrtab[ident=histo[r][g][b]], r, g, b);
375	+	/* find minimum */
376	+	for (p = nl[ident]; *p != ident; p++)
377	+	if ((d = dist(clrtab[*p], r, g, b)) < min) {
378	+	min = d;
379	+	histo[r][g][b] = *p;
380	+	}
381	+	}
382	+	#endif

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