1 |
greg |
1.1 |
/* Copyright (c) 1989 Regents of the University of California */ |
2 |
|
|
|
3 |
|
|
#ifndef lint |
4 |
|
|
static char SCCSid[] = "$SunId$ LBL"; |
5 |
|
|
#endif |
6 |
|
|
|
7 |
|
|
/* |
8 |
|
|
* colortab.c - allocate and control dynamic color table. |
9 |
|
|
* |
10 |
|
|
* We start off with a uniform partition of color space. |
11 |
|
|
* As pixels are sent to the frame buffer, a histogram is built. |
12 |
|
|
* When a new color table is requested, the histogram is used |
13 |
|
|
* to make a pseudo-optimal partition, after which the |
14 |
|
|
* histogram is cleared. This algorithm |
15 |
|
|
* performs only as well as the next drawing's color |
16 |
|
|
* distribution is correlated to the last. |
17 |
|
|
*/ |
18 |
|
|
|
19 |
|
|
#include "color.h" |
20 |
|
|
|
21 |
|
|
#define NULL 0 |
22 |
|
|
/* histogram resolution */ |
23 |
greg |
1.2 |
#define NRED 28 |
24 |
greg |
1.1 |
#define NGRN 32 |
25 |
greg |
1.2 |
#define NBLU 22 |
26 |
greg |
1.1 |
#define HMAX NGRN |
27 |
|
|
/* minimum box count for adaptive partition */ |
28 |
|
|
#define MINSAMP 7 |
29 |
|
|
/* maximum frame buffer depth */ |
30 |
|
|
#define FBDEPTH 8 |
31 |
|
|
/* color map resolution */ |
32 |
|
|
#define MAPSIZ 128 |
33 |
|
|
/* map a color */ |
34 |
|
|
#define map_col(c,p) clrmap[p][ colval(c,p)<1. ? \ |
35 |
|
|
(int)(colval(c,p)*MAPSIZ) : MAPSIZ-1 ] |
36 |
|
|
/* color partition tree */ |
37 |
|
|
#define CNODE short |
38 |
|
|
#define set_branch(p,c) ((c)<<2|(p)) |
39 |
|
|
#define set_pval(pv) ((pv)<<2|3) |
40 |
|
|
#define is_pval(cn) (((cn)&3)==3) |
41 |
|
|
#define part(cn) ((cn)>>2) |
42 |
|
|
#define prim(cn) ((cn)&3) |
43 |
|
|
#define pval(cn) ((cn)>>2) |
44 |
|
|
/* our color table */ |
45 |
|
|
COLR clrtab[1<<FBDEPTH]; |
46 |
|
|
/* our color correction map */ |
47 |
|
|
static BYTE clrmap[3][MAPSIZ]; |
48 |
|
|
/* histogram of colors used */ |
49 |
|
|
static unsigned histo[NRED][NGRN][NBLU]; |
50 |
|
|
/* initial color cube boundaries */ |
51 |
|
|
static int CLRCUBE[3][2] = {0,NRED,0,NGRN,0,NBLU}; |
52 |
|
|
/* color cube partition */ |
53 |
|
|
static CNODE ctree[1<<(FBDEPTH+1)]; |
54 |
|
|
|
55 |
|
|
|
56 |
|
|
COLR * |
57 |
|
|
get_ctab(ncolors) /* assign a color table with max ncolors */ |
58 |
|
|
int ncolors; |
59 |
|
|
{ |
60 |
|
|
if (ncolors < 1 || ncolors > 1<<FBDEPTH) |
61 |
|
|
return(NULL); |
62 |
|
|
/* partition color table */ |
63 |
|
|
cut(ctree, FBDEPTH, CLRCUBE, 0, ncolors); |
64 |
|
|
/* clear histogram */ |
65 |
|
|
bzero(histo, sizeof(histo)); |
66 |
|
|
/* return color table */ |
67 |
|
|
return(clrtab); |
68 |
|
|
} |
69 |
|
|
|
70 |
|
|
|
71 |
|
|
int |
72 |
|
|
get_pixel(col) /* get pixel for color */ |
73 |
|
|
COLOR col; |
74 |
|
|
{ |
75 |
|
|
int cv[3]; |
76 |
|
|
register CNODE *tp; |
77 |
|
|
register int h; |
78 |
|
|
/* map color */ |
79 |
|
|
cv[RED] = map_col(col,RED); |
80 |
|
|
cv[GRN] = map_col(col,GRN); |
81 |
|
|
cv[BLU] = map_col(col,BLU); |
82 |
|
|
/* add to histogram */ |
83 |
|
|
histo[cv[RED]][cv[GRN]][cv[BLU]]++; |
84 |
|
|
/* find pixel value in tree */ |
85 |
|
|
tp = ctree; |
86 |
|
|
for (h = FBDEPTH; h > 0; h--) { |
87 |
|
|
if (is_pval(*tp)) |
88 |
|
|
break; |
89 |
|
|
if (cv[prim(*tp)] < part(*tp)) |
90 |
|
|
tp++; /* left branch */ |
91 |
|
|
else |
92 |
|
|
tp += 1<<h; /* right branch */ |
93 |
|
|
} |
94 |
|
|
#ifdef notdef |
95 |
|
|
printf("distance (%d,%d,%d)\n", |
96 |
|
|
cv[RED] - clrtab[pval(*tp)][RED]*NRED/256, |
97 |
|
|
cv[GRN] - clrtab[pval(*tp)][GRN]*NGRN/256, |
98 |
|
|
cv[BLU] - clrtab[pval(*tp)][BLU]*NBLU/256); |
99 |
|
|
#endif |
100 |
|
|
return(pval(*tp)); |
101 |
|
|
} |
102 |
|
|
|
103 |
|
|
|
104 |
|
|
make_cmap(gam) /* make gamma correction map */ |
105 |
|
|
double gam; |
106 |
|
|
{ |
107 |
|
|
extern double pow(); |
108 |
|
|
double d; |
109 |
|
|
register int i; |
110 |
|
|
|
111 |
|
|
for (i = 0; i < MAPSIZ; i++) { |
112 |
|
|
d = pow(i/(double)MAPSIZ, 1.0/gam); |
113 |
|
|
clrmap[RED][i] = d * NRED; |
114 |
|
|
clrmap[GRN][i] = d * NGRN; |
115 |
|
|
clrmap[BLU][i] = d * NBLU; |
116 |
|
|
} |
117 |
|
|
} |
118 |
|
|
|
119 |
|
|
|
120 |
|
|
static |
121 |
|
|
cut(tree, height, box, c0, c1) /* partition color space */ |
122 |
|
|
register CNODE *tree; |
123 |
|
|
int height; |
124 |
|
|
register int box[3][2]; |
125 |
|
|
int c0, c1; |
126 |
|
|
{ |
127 |
|
|
int kb[3][2]; |
128 |
|
|
|
129 |
|
|
if (c1-c0 == 1) { /* assign color */ |
130 |
|
|
clrtab[c0][RED] = ((box[RED][0]+box[RED][1])<<7)/NRED; |
131 |
|
|
clrtab[c0][GRN] = ((box[GRN][0]+box[GRN][1])<<7)/NGRN; |
132 |
|
|
clrtab[c0][BLU] = ((box[BLU][0]+box[BLU][1])<<7)/NBLU; |
133 |
|
|
clrtab[c0][EXP] = COLXS; |
134 |
|
|
*tree = set_pval(c0); |
135 |
|
|
#ifdef notdef |
136 |
|
|
printf("final box size = (%d,%d,%d)\n", |
137 |
|
|
box[RED][1] - box[RED][0], |
138 |
|
|
box[GRN][1] - box[GRN][0], |
139 |
|
|
box[BLU][1] - box[BLU][0]); |
140 |
|
|
#endif |
141 |
|
|
return; |
142 |
|
|
} |
143 |
|
|
/* split box */ |
144 |
|
|
*tree = split(box); |
145 |
|
|
bcopy(box, kb, sizeof(kb)); |
146 |
|
|
kb[prim(*tree)][1] = part(*tree); |
147 |
|
|
cut(tree+1, height-1, kb, c0, (c0+c1)>>1); /* lesser */ |
148 |
|
|
kb[prim(*tree)][0] = part(*tree); |
149 |
|
|
kb[prim(*tree)][1] = box[prim(*tree)][1]; |
150 |
|
|
cut(tree+(1<<height), height-1, kb, (c0+c1)>>1, c1); /* greater */ |
151 |
|
|
} |
152 |
|
|
|
153 |
|
|
|
154 |
|
|
static int |
155 |
|
|
split(box) /* find median cut for box */ |
156 |
|
|
register int box[3][2]; |
157 |
|
|
{ |
158 |
|
|
#define c0 r |
159 |
|
|
register int r, g, b; |
160 |
|
|
int pri; |
161 |
|
|
int t[HMAX], med; |
162 |
|
|
/* find dominant axis */ |
163 |
|
|
pri = RED; |
164 |
|
|
if (box[GRN][1]-box[GRN][0] > box[pri][1]-box[pri][0]) |
165 |
|
|
pri = GRN; |
166 |
|
|
if (box[BLU][1]-box[BLU][0] > box[pri][1]-box[pri][0]) |
167 |
|
|
pri = BLU; |
168 |
|
|
/* sum histogram over box */ |
169 |
|
|
med = 0; |
170 |
|
|
switch (pri) { |
171 |
|
|
case RED: |
172 |
|
|
for (r = box[RED][0]; r < box[RED][1]; r++) { |
173 |
|
|
t[r] = 0; |
174 |
|
|
for (g = box[GRN][0]; g < box[GRN][1]; g++) |
175 |
|
|
for (b = box[BLU][0]; b < box[BLU][1]; b++) |
176 |
|
|
t[r] += histo[r][g][b]; |
177 |
|
|
med += t[r]; |
178 |
|
|
} |
179 |
|
|
break; |
180 |
|
|
case GRN: |
181 |
|
|
for (g = box[GRN][0]; g < box[GRN][1]; g++) { |
182 |
|
|
t[g] = 0; |
183 |
|
|
for (b = box[BLU][0]; b < box[BLU][1]; b++) |
184 |
|
|
for (r = box[RED][0]; r < box[RED][1]; r++) |
185 |
|
|
t[g] += histo[r][g][b]; |
186 |
|
|
med += t[g]; |
187 |
|
|
} |
188 |
|
|
break; |
189 |
|
|
case BLU: |
190 |
|
|
for (b = box[BLU][0]; b < box[BLU][1]; b++) { |
191 |
|
|
t[b] = 0; |
192 |
|
|
for (r = box[RED][0]; r < box[RED][1]; r++) |
193 |
|
|
for (g = box[GRN][0]; g < box[GRN][1]; g++) |
194 |
|
|
t[b] += histo[r][g][b]; |
195 |
|
|
med += t[b]; |
196 |
|
|
} |
197 |
|
|
break; |
198 |
|
|
} |
199 |
|
|
if (med < MINSAMP) /* if too sparse, split at midpoint */ |
200 |
|
|
return(set_branch(pri,(box[pri][0]+box[pri][1])>>1)); |
201 |
|
|
/* find median position */ |
202 |
|
|
med >>= 1; |
203 |
|
|
for (c0 = box[pri][0]; med > 0; c0++) |
204 |
|
|
med -= t[c0]; |
205 |
|
|
if (c0 > (box[pri][0]+box[pri][1])>>1) /* if past the midpoint */ |
206 |
|
|
c0--; /* part left of median */ |
207 |
|
|
return(set_branch(pri,c0)); |
208 |
|
|
#undef c0 |
209 |
|
|
} |