src/hd/rhd_ctab.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#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 "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 */
        bzero((void *)histo, 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);
        bcopy((void *)box, (void *)kb, 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:	3.3
Committed:	Tue May 13 17:58:33 2003 UTC (20 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 3.2:	+2 -2 lines
Log Message:	Changed (char ) casts for memory copies to (void ) and other fixes
#	User	Rev	Content
1	gregl	3.1	#ifndef lint
2	greg	3.2	static const char RCSid[] = "$Id$";
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			#include "standard.h"
20			#include "color.h"
21			/* histogram resolution */
22			#define NRED 24
23			#define NGRN 32
24			#define NBLU 16
25			#define HMAX NGRN
26			/* minimum box count for adaptive partition */
27			#define MINSAMP 7
28			/* maximum distance^2 before color reassign */
29			#define MAXDST2 12
30			/* color partition tree */
31			#define CNODE short
32			#define set_branch(p,c) ((c)<<2\|(p))
33			#define set_pval(pv) ((pv)<<2\|3)
34			#define is_branch(cn) (((cn)&3)!=3)
35			#define is_pval(cn) (((cn)&3)==3)
36			#define part(cn) ((cn)>>2)
37			#define prim(cn) ((cn)&3)
38			#define pval(cn) ((cn)>>2)
39			/* our color table */
40			static struct tabent {
41			long sum[3]; /* sum of colors using this entry */
42			int n; /* number of colors */
43			BYTE ent[3]; /* current table value */
44			} *clrtab = NULL;
45			/* color cube partition */
46			static CNODE *ctree = NULL;
47			/* histogram of colors used */
48			static unsigned short histo[NRED][NGRN][NBLU];
49			/* initial color cube boundary */
50			static int CLRCUBE[3][2] = {{0,NRED},{0,NGRN},{0,NBLU}};
51
52			static int split(), cut();
53
54
55			int
56			new_ctab(ncolors) /* start new color table with max ncolors */
57			int ncolors;
58			{
59			int treesize;
60
61			if (ncolors < 1)
62			return(0);
63			/* free old tables */
64			if (clrtab != NULL)
65	greg	3.2	free((void *)clrtab);
66	gregl	3.1	if (ctree != NULL)
67	greg	3.2	free((void *)ctree);
68	gregl	3.1	/* get new tables */
69			for (treesize = 1; treesize < ncolors; treesize <<= 1)
70			;
71			treesize <<= 1;
72			clrtab = (struct tabent *)calloc(ncolors, sizeof(struct tabent));
73			ctree = (CNODE )malloc(treesizesizeof(CNODE));
74			if (clrtab == NULL \|\| ctree == NULL)
75			return(0);
76			/* partition color space */
77			cut(ctree, 0, CLRCUBE, 0, ncolors);
78			/* clear histogram */
79	greg	3.3	bzero((void *)histo, sizeof(histo));
80	gregl	3.1	/* return number of colors used */
81			return(ncolors);
82			}
83
84
85			int
86			get_pixel(rgb, set_pixel) /* get pixel for color */
87			BYTE rgb[3];
88			int (*set_pixel)();
89			{
90			extern char errmsg[];
91			int r, g, b;
92			int cv[3];
93			register CNODE *tp;
94			register int h;
95			/* get desired color */
96			r = rgb[RED];
97			g = rgb[GRN];
98			b = rgb[BLU];
99			/* reduce resolution */
100			cv[RED] = (r*NRED)>>8;
101			cv[GRN] = (g*NGRN)>>8;
102			cv[BLU] = (b*NBLU)>>8;
103			/* add to histogram */
104			histo[cv[RED]][cv[GRN]][cv[BLU]]++;
105			/* find pixel in tree */
106			for (tp = ctree, h = 0; is_branch(*tp); h++)
107			if (cv[prim(tp)] < part(tp))
108			tp += 1<<h; /* left branch */
109			else
110			tp += 1<<(h+1); /* right branch */
111			h = pval(*tp);
112			/* add to color table */
113			clrtab[h].sum[RED] += r;
114			clrtab[h].sum[GRN] += g;
115			clrtab[h].sum[BLU] += b;
116			clrtab[h].n++;
117			/* recompute average */
118			r = clrtab[h].sum[RED] / clrtab[h].n;
119			g = clrtab[h].sum[GRN] / clrtab[h].n;
120			b = clrtab[h].sum[BLU] / clrtab[h].n;
121			/* check for movement */
122			if (clrtab[h].n == 1 \|\|
123			(r-clrtab[h].ent[RED])*(r-clrtab[h].ent[RED]) +
124			(g-clrtab[h].ent[GRN])*(g-clrtab[h].ent[GRN]) +
125			(b-clrtab[h].ent[BLU])*(b-clrtab[h].ent[BLU]) > MAXDST2) {
126			clrtab[h].ent[RED] = r;
127			clrtab[h].ent[GRN] = g; /* reassign pixel */
128			clrtab[h].ent[BLU] = b;
129			#ifdef DEBUG
130			sprintf(errmsg, "pixel %d = (%d,%d,%d) (%d refs)\n",
131			h, r, g, b, clrtab[h].n);
132			eputs(errmsg);
133			#endif
134			(*set_pixel)(h, r, g, b);
135			}
136			return(h); /* return pixel value */
137			}
138
139
140			static
141			cut(tree, level, box, c0, c1) /* partition color space */
142			register CNODE *tree;
143			int level;
144			register int box[3][2];
145			int c0, c1;
146			{
147			int kb[3][2];
148
149			if (c1-c0 <= 1) { /* assign pixel */
150			*tree = set_pval(c0);
151			return;
152			}
153			/* split box */
154			*tree = split(box);
155	greg	3.3	bcopy((void )box, (void )kb, sizeof(kb));
156	gregl	3.1	/* do left (lesser) branch */
157			kb[prim(tree)][1] = part(tree);
158			cut(tree+(1<<level), level+1, kb, c0, (c0+c1)>>1);
159			/* do right branch */
160			kb[prim(tree)][0] = part(tree);
161			kb[prim(tree)][1] = box[prim(tree)][1];
162			cut(tree+(1<<(level+1)), level+1, kb, (c0+c1)>>1, c1);
163			}
164
165
166			static int
167			split(box) /* find median cut for box */
168			register int box[3][2];
169			{
170			#define c0 r
171			register int r, g, b;
172			int pri;
173			long t[HMAX], med;
174			/* find dominant axis */
175			pri = RED;
176			if (box[GRN][1]-box[GRN][0] > box[pri][1]-box[pri][0])
177			pri = GRN;
178			if (box[BLU][1]-box[BLU][0] > box[pri][1]-box[pri][0])
179			pri = BLU;
180			/* sum histogram over box */
181			med = 0;
182			switch (pri) {
183			case RED:
184			for (r = box[RED][0]; r < box[RED][1]; r++) {
185			t[r] = 0;
186			for (g = box[GRN][0]; g < box[GRN][1]; g++)
187			for (b = box[BLU][0]; b < box[BLU][1]; b++)
188			t[r] += histo[r][g][b];
189			med += t[r];
190			}
191			break;
192			case GRN:
193			for (g = box[GRN][0]; g < box[GRN][1]; g++) {
194			t[g] = 0;
195			for (b = box[BLU][0]; b < box[BLU][1]; b++)
196			for (r = box[RED][0]; r < box[RED][1]; r++)
197			t[g] += histo[r][g][b];
198			med += t[g];
199			}
200			break;
201			case BLU:
202			for (b = box[BLU][0]; b < box[BLU][1]; b++) {
203			t[b] = 0;
204			for (r = box[RED][0]; r < box[RED][1]; r++)
205			for (g = box[GRN][0]; g < box[GRN][1]; g++)
206			t[b] += histo[r][g][b];
207			med += t[b];
208			}
209			break;
210			}
211			if (med < MINSAMP) /* if too sparse, split at midpoint */
212			return(set_branch(pri,(box[pri][0]+box[pri][1])>>1));
213			/* find median position */
214			med >>= 1;
215			for (c0 = box[pri][0]; med > 0; c0++)
216			med -= t[c0];
217			if (c0 > (box[pri][0]+box[pri][1])>>1) /* if past the midpoint */
218			c0--; /* part left of median */
219			return(set_branch(pri,c0));
220			#undef c0
221			}