src/hd/rhd_ctab.c

#ifndef lint
static const char       RCSid[] = "$Id: rhd_ctab.c,v 3.3 2003/05/13 17:58:33 greg Exp $";
#endif
/*
 * Allocate and control dynamic color table.
 *
 *      We start off with a uniform partition of color space.
 *      As pixels are sent to the frame buffer, a histogram is built.
 *      When a new color table is requested, the histogram is used
 *      to make a pseudo-optimal partition, after which the
 *      histogram is cleared.  This algorithm
 *      performs only as well as the next drawing's color
 *      distribution is correlated to the last.
 *
 *      This module is essentially identical to src/rt/colortab.c,
 *      except there is no color mapping, since the tm library is used.
 */

#include <string.h>

#include "standard.h"
#include "color.h"
                                /* histogram resolution */
#define NRED            24
#define NGRN            32
#define NBLU            16
#define HMAX            NGRN
                                /* minimum box count for adaptive partition */
#define MINSAMP         7
                                /* maximum distance^2 before color reassign */
#define MAXDST2         12
                                /* color partition tree */
#define CNODE           short
#define set_branch(p,c) ((c)<<2|(p))
#define set_pval(pv)    ((pv)<<2|3)
#define is_branch(cn)   (((cn)&3)!=3)
#define is_pval(cn)     (((cn)&3)==3)
#define part(cn)        ((cn)>>2)
#define prim(cn)        ((cn)&3)
#define pval(cn)        ((cn)>>2)
                                /* our color table */
static struct tabent {
        long    sum[3];         /* sum of colors using this entry */
        int     n;              /* number of colors */
        BYTE    ent[3];         /* current table value */
}       *clrtab = NULL;
                                /* color cube partition */
static CNODE    *ctree = NULL;
                                /* histogram of colors used */
static unsigned short   histo[NRED][NGRN][NBLU];
                                /* initial color cube boundary */
static int      CLRCUBE[3][2] = {{0,NRED},{0,NGRN},{0,NBLU}};

static int      split(), cut();


int
new_ctab(ncolors)               /* start new color table with max ncolors */
int     ncolors;
{
        int     treesize;

        if (ncolors < 1)
                return(0);
                                /* free old tables */
        if (clrtab != NULL)
                free((void *)clrtab);
        if (ctree != NULL)
                free((void *)ctree);
                                /* get new tables */
        for (treesize = 1; treesize < ncolors; treesize <<= 1)
                ;
        treesize <<= 1;
        clrtab = (struct tabent *)calloc(ncolors, sizeof(struct tabent));
        ctree = (CNODE *)malloc(treesize*sizeof(CNODE));
        if (clrtab == NULL || ctree == NULL)
                return(0);
                                /* partition color space */
        cut(ctree, 0, CLRCUBE, 0, ncolors);
                                /* clear histogram */
        memset((void *)histo, '\0', sizeof(histo));
                                /* return number of colors used */
        return(ncolors);
}


int
get_pixel(rgb, set_pixel)       /* get pixel for color */
BYTE    rgb[3];
int     (*set_pixel)();
{
        extern char     errmsg[];
        int     r, g, b;
        int     cv[3];
        register CNODE  *tp;
        register int    h;
                                                /* get desired color */
        r = rgb[RED];
        g = rgb[GRN];
        b = rgb[BLU];
                                                /* reduce resolution */
        cv[RED] = (r*NRED)>>8;
        cv[GRN] = (g*NGRN)>>8;
        cv[BLU] = (b*NBLU)>>8;
                                                /* add to histogram */
        histo[cv[RED]][cv[GRN]][cv[BLU]]++;
                                                /* find pixel in tree */
        for (tp = ctree, h = 0; is_branch(*tp); h++)
                if (cv[prim(*tp)] < part(*tp))
                        tp += 1<<h;             /* left branch */
                else
                        tp += 1<<(h+1);         /* right branch */
        h = pval(*tp);
                                                /* add to color table */
        clrtab[h].sum[RED] += r;
        clrtab[h].sum[GRN] += g;
        clrtab[h].sum[BLU] += b;
        clrtab[h].n++;
                                        /* recompute average */
        r = clrtab[h].sum[RED] / clrtab[h].n;
        g = clrtab[h].sum[GRN] / clrtab[h].n;
        b = clrtab[h].sum[BLU] / clrtab[h].n;
                                        /* check for movement */
        if (clrtab[h].n == 1 ||
                        (r-clrtab[h].ent[RED])*(r-clrtab[h].ent[RED]) +
                        (g-clrtab[h].ent[GRN])*(g-clrtab[h].ent[GRN]) +
                        (b-clrtab[h].ent[BLU])*(b-clrtab[h].ent[BLU]) > MAXDST2) {
                clrtab[h].ent[RED] = r;
                clrtab[h].ent[GRN] = g; /* reassign pixel */
                clrtab[h].ent[BLU] = b;
#ifdef DEBUG
                sprintf(errmsg, "pixel %d = (%d,%d,%d) (%d refs)\n",
                                h, r, g, b, clrtab[h].n);
                eputs(errmsg);
#endif
                (*set_pixel)(h, r, g, b);
        }
        return(h);                              /* return pixel value */
}


static
cut(tree, level, box, c0, c1)           /* partition color space */
register CNODE  *tree;
int     level;
register int    box[3][2];
int     c0, c1;
{
        int     kb[3][2];
        
        if (c1-c0 <= 1) {               /* assign pixel */
                *tree = set_pval(c0);
                return;
        }
                                        /* split box */
        *tree = split(box);
        memcpy((void *)kb, (void *)box, sizeof(kb));
                                                /* do left (lesser) branch */
        kb[prim(*tree)][1] = part(*tree);
        cut(tree+(1<<level), level+1, kb, c0, (c0+c1)>>1);
                                                /* do right branch */
        kb[prim(*tree)][0] = part(*tree);
        kb[prim(*tree)][1] = box[prim(*tree)][1];
        cut(tree+(1<<(level+1)), level+1, kb, (c0+c1)>>1, c1);
}


static int
split(box)                              /* find median cut for box */
register int    box[3][2];
{
#define c0      r
        register int    r, g, b;
        int     pri;
        long    t[HMAX], med;
                                        /* find dominant axis */
        pri = RED;
        if (box[GRN][1]-box[GRN][0] > box[pri][1]-box[pri][0])
                pri = GRN;
        if (box[BLU][1]-box[BLU][0] > box[pri][1]-box[pri][0])
                pri = BLU;
                                        /* sum histogram over box */
        med = 0;
        switch (pri) {
        case RED:
                for (r = box[RED][0]; r < box[RED][1]; r++) {
                        t[r] = 0;
                        for (g = box[GRN][0]; g < box[GRN][1]; g++)
                                for (b = box[BLU][0]; b < box[BLU][1]; b++)
                                        t[r] += histo[r][g][b];
                        med += t[r];
                }
                break;
        case GRN:
                for (g = box[GRN][0]; g < box[GRN][1]; g++) {
                        t[g] = 0;
                        for (b = box[BLU][0]; b < box[BLU][1]; b++)
                                for (r = box[RED][0]; r < box[RED][1]; r++)
                                        t[g] += histo[r][g][b];
                        med += t[g];
                }
                break;
        case BLU:
                for (b = box[BLU][0]; b < box[BLU][1]; b++) {
                        t[b] = 0;
                        for (r = box[RED][0]; r < box[RED][1]; r++)
                                for (g = box[GRN][0]; g < box[GRN][1]; g++)
                                        t[b] += histo[r][g][b];
                        med += t[b];
                }
                break;
        }
        if (med < MINSAMP)              /* if too sparse, split at midpoint */
                return(set_branch(pri,(box[pri][0]+box[pri][1])>>1));
                                        /* find median position */
        med >>= 1;
        for (c0 = box[pri][0]; med > 0; c0++)
                med -= t[c0];
        if (c0 > (box[pri][0]+box[pri][1])>>1)  /* if past the midpoint */
                c0--;                           /* part left of median */
        return(set_branch(pri,c0));
#undef c0
}
Revision:	3.4
Committed:	Mon Jun 30 14:59:11 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 3.3:	+5 -3 lines
Log Message:	Replaced most outdated BSD function calls with their posix equivalents, and cleaned up a few other platform dependencies.
#	User	Rev	Content
1	gregl	3.1	#ifndef lint
2	schorsch	3.4	static const char RCSid[] = "$Id: rhd_ctab.c,v 3.3 2003/05/13 17:58:33 greg Exp $";
3	gregl	3.1	#endif
4			/*
5			* Allocate and control dynamic color table.
6			*
7			* We start off with a uniform partition of color space.
8			* As pixels are sent to the frame buffer, a histogram is built.
9			* When a new color table is requested, the histogram is used
10			* to make a pseudo-optimal partition, after which the
11			* histogram is cleared. This algorithm
12			* performs only as well as the next drawing's color
13			* distribution is correlated to the last.
14			*
15			* This module is essentially identical to src/rt/colortab.c,
16			* except there is no color mapping, since the tm library is used.
17			*/
18
19	schorsch	3.4	#include <string.h>
20
21	gregl	3.1	#include "standard.h"
22			#include "color.h"
23			/* histogram resolution */
24			#define NRED 24
25			#define NGRN 32
26			#define NBLU 16
27			#define HMAX NGRN
28			/* minimum box count for adaptive partition */
29			#define MINSAMP 7
30			/* maximum distance^2 before color reassign */
31			#define MAXDST2 12
32			/* color partition tree */
33			#define CNODE short
34			#define set_branch(p,c) ((c)<<2\|(p))
35			#define set_pval(pv) ((pv)<<2\|3)
36			#define is_branch(cn) (((cn)&3)!=3)
37			#define is_pval(cn) (((cn)&3)==3)
38			#define part(cn) ((cn)>>2)
39			#define prim(cn) ((cn)&3)
40			#define pval(cn) ((cn)>>2)
41			/* our color table */
42			static struct tabent {
43			long sum[3]; /* sum of colors using this entry */
44			int n; /* number of colors */
45			BYTE ent[3]; /* current table value */
46			} *clrtab = NULL;
47			/* color cube partition */
48			static CNODE *ctree = NULL;
49			/* histogram of colors used */
50			static unsigned short histo[NRED][NGRN][NBLU];
51			/* initial color cube boundary */
52			static int CLRCUBE[3][2] = {{0,NRED},{0,NGRN},{0,NBLU}};
53
54			static int split(), cut();
55
56
57			int
58			new_ctab(ncolors) /* start new color table with max ncolors */
59			int ncolors;
60			{
61			int treesize;
62
63			if (ncolors < 1)
64			return(0);
65			/* free old tables */
66			if (clrtab != NULL)
67	greg	3.2	free((void *)clrtab);
68	gregl	3.1	if (ctree != NULL)
69	greg	3.2	free((void *)ctree);
70	gregl	3.1	/* get new tables */
71			for (treesize = 1; treesize < ncolors; treesize <<= 1)
72			;
73			treesize <<= 1;
74			clrtab = (struct tabent *)calloc(ncolors, sizeof(struct tabent));
75			ctree = (CNODE )malloc(treesizesizeof(CNODE));
76			if (clrtab == NULL \|\| ctree == NULL)
77			return(0);
78			/* partition color space */
79			cut(ctree, 0, CLRCUBE, 0, ncolors);
80			/* clear histogram */
81	schorsch	3.4	memset((void *)histo, '\0', sizeof(histo));
82	gregl	3.1	/* return number of colors used */
83			return(ncolors);
84			}
85
86
87			int
88			get_pixel(rgb, set_pixel) /* get pixel for color */
89			BYTE rgb[3];
90			int (*set_pixel)();
91			{
92			extern char errmsg[];
93			int r, g, b;
94			int cv[3];
95			register CNODE *tp;
96			register int h;
97			/* get desired color */
98			r = rgb[RED];
99			g = rgb[GRN];
100			b = rgb[BLU];
101			/* reduce resolution */
102			cv[RED] = (r*NRED)>>8;
103			cv[GRN] = (g*NGRN)>>8;
104			cv[BLU] = (b*NBLU)>>8;
105			/* add to histogram */
106			histo[cv[RED]][cv[GRN]][cv[BLU]]++;
107			/* find pixel in tree */
108			for (tp = ctree, h = 0; is_branch(*tp); h++)
109			if (cv[prim(tp)] < part(tp))
110			tp += 1<<h; /* left branch */
111			else
112			tp += 1<<(h+1); /* right branch */
113			h = pval(*tp);
114			/* add to color table */
115			clrtab[h].sum[RED] += r;
116			clrtab[h].sum[GRN] += g;
117			clrtab[h].sum[BLU] += b;
118			clrtab[h].n++;
119			/* recompute average */
120			r = clrtab[h].sum[RED] / clrtab[h].n;
121			g = clrtab[h].sum[GRN] / clrtab[h].n;
122			b = clrtab[h].sum[BLU] / clrtab[h].n;
123			/* check for movement */
124			if (clrtab[h].n == 1 \|\|
125			(r-clrtab[h].ent[RED])*(r-clrtab[h].ent[RED]) +
126			(g-clrtab[h].ent[GRN])*(g-clrtab[h].ent[GRN]) +
127			(b-clrtab[h].ent[BLU])*(b-clrtab[h].ent[BLU]) > MAXDST2) {
128			clrtab[h].ent[RED] = r;
129			clrtab[h].ent[GRN] = g; /* reassign pixel */
130			clrtab[h].ent[BLU] = b;
131			#ifdef DEBUG
132			sprintf(errmsg, "pixel %d = (%d,%d,%d) (%d refs)\n",
133			h, r, g, b, clrtab[h].n);
134			eputs(errmsg);
135			#endif
136			(*set_pixel)(h, r, g, b);
137			}
138			return(h); /* return pixel value */
139			}
140
141
142			static
143			cut(tree, level, box, c0, c1) /* partition color space */
144			register CNODE *tree;
145			int level;
146			register int box[3][2];
147			int c0, c1;
148			{
149			int kb[3][2];
150
151			if (c1-c0 <= 1) { /* assign pixel */
152			*tree = set_pval(c0);
153			return;
154			}
155			/* split box */
156			*tree = split(box);
157	schorsch	3.4	memcpy((void )kb, (void )box, sizeof(kb));
158	gregl	3.1	/* do left (lesser) branch */
159			kb[prim(tree)][1] = part(tree);
160			cut(tree+(1<<level), level+1, kb, c0, (c0+c1)>>1);
161			/* do right branch */
162			kb[prim(tree)][0] = part(tree);
163			kb[prim(tree)][1] = box[prim(tree)][1];
164			cut(tree+(1<<(level+1)), level+1, kb, (c0+c1)>>1, c1);
165			}
166
167
168			static int
169			split(box) /* find median cut for box */
170			register int box[3][2];
171			{
172			#define c0 r
173			register int r, g, b;
174			int pri;
175			long t[HMAX], med;
176			/* find dominant axis */
177			pri = RED;
178			if (box[GRN][1]-box[GRN][0] > box[pri][1]-box[pri][0])
179			pri = GRN;
180			if (box[BLU][1]-box[BLU][0] > box[pri][1]-box[pri][0])
181			pri = BLU;
182			/* sum histogram over box */
183			med = 0;
184			switch (pri) {
185			case RED:
186			for (r = box[RED][0]; r < box[RED][1]; r++) {
187			t[r] = 0;
188			for (g = box[GRN][0]; g < box[GRN][1]; g++)
189			for (b = box[BLU][0]; b < box[BLU][1]; b++)
190			t[r] += histo[r][g][b];
191			med += t[r];
192			}
193			break;
194			case GRN:
195			for (g = box[GRN][0]; g < box[GRN][1]; g++) {
196			t[g] = 0;
197			for (b = box[BLU][0]; b < box[BLU][1]; b++)
198			for (r = box[RED][0]; r < box[RED][1]; r++)
199			t[g] += histo[r][g][b];
200			med += t[g];
201			}
202			break;
203			case BLU:
204			for (b = box[BLU][0]; b < box[BLU][1]; b++) {
205			t[b] = 0;
206			for (r = box[RED][0]; r < box[RED][1]; r++)
207			for (g = box[GRN][0]; g < box[GRN][1]; g++)
208			t[b] += histo[r][g][b];
209			med += t[b];
210			}
211			break;
212			}
213			if (med < MINSAMP) /* if too sparse, split at midpoint */
214			return(set_branch(pri,(box[pri][0]+box[pri][1])>>1));
215			/* find median position */
216			med >>= 1;
217			for (c0 = box[pri][0]; med > 0; c0++)
218			med -= t[c0];
219			if (c0 > (box[pri][0]+box[pri][1])>>1) /* if past the midpoint */
220			c0--; /* part left of median */
221			return(set_branch(pri,c0));
222			#undef c0
223			}