1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: color.c,v 2.32 2023/12/07 23:16:58 greg Exp $"; |
3 |
#endif |
4 |
/* |
5 |
* color.c - routines for color calculations. |
6 |
* |
7 |
* Externals declared in color.h |
8 |
*/ |
9 |
|
10 |
#include "copyright.h" |
11 |
|
12 |
#include <stdio.h> |
13 |
#include <stdlib.h> |
14 |
#include <math.h> |
15 |
#include "color.h" |
16 |
|
17 |
#ifdef getc_unlocked /* avoid horrendous overhead of flockfile */ |
18 |
#undef getc |
19 |
#undef putc |
20 |
#undef ferror |
21 |
#define getc getc_unlocked |
22 |
#define putc putc_unlocked |
23 |
#define ferror ferror_unlocked |
24 |
#endif |
25 |
|
26 |
#define MINELEN 8 /* minimum scanline length for encoding */ |
27 |
#define MAXELEN 0x7fff /* maximum scanline length for encoding */ |
28 |
#define MINRUN 4 /* minimum run length */ |
29 |
|
30 |
|
31 |
int CNDX[4] = {0,1,2,3}; /* RGBE indices for SCOLOR, SCOLR */ |
32 |
float WLPART[4] = {780,588,480,380}; /* RGB wavelength limits+partitions (nm) */ |
33 |
|
34 |
|
35 |
int |
36 |
setspectrsamp( /* assign spectral sampling, 1 if good, -1 if bad */ |
37 |
int cn[4], /* input cn[3]=nsamps */ |
38 |
float wlpt[4] /* input wlpt[0],wlpt[3]=extrema */ |
39 |
) |
40 |
{ |
41 |
static const float PKWL[3] = {607, 553, 469}; |
42 |
int i, j; |
43 |
|
44 |
if (cn[3] < 3) |
45 |
return(-1); /* reject this */ |
46 |
|
47 |
if (wlpt[0] < wlpt[3]) { |
48 |
float tf = wlpt[0]; |
49 |
wlpt[0] = wlpt[3]; wlpt[3] = tf; |
50 |
} |
51 |
if (wlpt[0] - wlpt[3] < 50.f) |
52 |
return(-1); /* also reject */ |
53 |
|
54 |
if (cn[3] > MAXCSAMP) |
55 |
cn[3] = MAXCSAMP; |
56 |
|
57 |
if ((wlpt[3] >= PKWL[2]) | (wlpt[0] <= PKWL[0])) { |
58 |
wlpt[1] = wlpt[0] + 0.333333f*(wlpt[3]-wlpt[0]); |
59 |
wlpt[2] = wlpt[0] + 0.666667f*(wlpt[3]-wlpt[0]); |
60 |
cn[0] = 0; cn[1] = cn[3]/3; cn[2] = cn[3]*2/3; |
61 |
return(0); /* unhappy but non-fatal return value */ |
62 |
} |
63 |
wlpt[1] = 588.f; /* tuned for standard green channel */ |
64 |
wlpt[2] = 480.f; |
65 |
if (cn[3] == 3) { /* nothing to tune? */ |
66 |
cn[0] = 0; cn[1] = 1; cn[2] = 2; |
67 |
} else { /* else find nearest color indices */ |
68 |
double curwl[3]; |
69 |
memset(curwl, 0, sizeof(curwl)); |
70 |
for (i = cn[3]; i--; ) { |
71 |
const float cwl = (i+.5f)/cn[3]*(wlpt[3]-wlpt[0]) + wlpt[0]; |
72 |
for (j = 3; j--; ) |
73 |
if (fabs(cwl - PKWL[j]) < fabs(curwl[j] - PKWL[j])) { |
74 |
curwl[j] = cwl; |
75 |
cn[j] = i; |
76 |
} |
77 |
} |
78 |
} |
79 |
return(1); /* happy return value */ |
80 |
} |
81 |
|
82 |
|
83 |
void |
84 |
setscolor( /* assign spectral color from RGB */ |
85 |
SCOLOR scol, |
86 |
double r, |
87 |
double g, |
88 |
double b |
89 |
) |
90 |
{ |
91 |
const double step = (WLPART[3] - WLPART[0])/(double)NCSAMP; |
92 |
double cwl = WLPART[0] + .5*step; |
93 |
int i; |
94 |
|
95 |
for (i = 0; i < NCSAMP; i++) { |
96 |
if (cwl >= WLPART[1]) |
97 |
scol[i] = r; |
98 |
else if (cwl >= WLPART[2]) |
99 |
scol[i] = g; |
100 |
else |
101 |
scol[i] = b; |
102 |
cwl += step; |
103 |
} |
104 |
} |
105 |
|
106 |
|
107 |
void |
108 |
scolor2color( /* assign RGB color from spectrum */ |
109 |
COLOR col, |
110 |
SCOLOR scol, /* uses average over bands */ |
111 |
int ncs, |
112 |
const float wlpt[4] |
113 |
) |
114 |
{ |
115 |
const double step = (wlpt[3] - wlpt[0])/(double)ncs; |
116 |
double cwl = wlpt[0] + .5*step; |
117 |
int i, j=0, n=0; |
118 |
|
119 |
setcolor(col, 0, 0, 0); |
120 |
for (i = 0; i < ncs; i++) { |
121 |
if (cwl < wlpt[j+1]) { |
122 |
if (n > 1) col[j] /= (COLORV)n; |
123 |
j++; |
124 |
n = 0; |
125 |
} |
126 |
col[j] += scol[i]; |
127 |
n++; |
128 |
cwl += step; |
129 |
} |
130 |
if (n > 1) col[j] /= (COLORV)n; |
131 |
} |
132 |
|
133 |
|
134 |
void |
135 |
scolor2colr( /* assign RGBE from spectral color */ |
136 |
COLR clr, |
137 |
SCOLOR scol, /* uses average over bands */ |
138 |
int ncs, |
139 |
const float wlpt[4] |
140 |
) |
141 |
{ |
142 |
COLOR col; |
143 |
|
144 |
scolor2color(col, scol, ncs, wlpt); |
145 |
setcolr(clr, col[RED], col[GRN], col[BLU]); |
146 |
} |
147 |
|
148 |
|
149 |
void |
150 |
scolr2color( /* assign RGB from common exponent */ |
151 |
COLOR col, |
152 |
SCOLR sclr, |
153 |
int ncs, |
154 |
const float wlpt[4] |
155 |
) |
156 |
{ |
157 |
SCOLOR scol; |
158 |
|
159 |
scolr2scolor(scol, sclr, ncs); |
160 |
scolor2color(col, scol, ncs, wlpt); |
161 |
} |
162 |
|
163 |
|
164 |
void |
165 |
scolor2scolr( /* float spectrum to common exponent */ |
166 |
SCOLR sclr, |
167 |
SCOLOR scol, |
168 |
int ncs |
169 |
) |
170 |
{ |
171 |
int i = ncs; |
172 |
COLORV p = scol[--i]; |
173 |
|
174 |
while (i) |
175 |
if (scol[--i] > p) |
176 |
p = scol[i]; |
177 |
if (p <= 1e-32) { |
178 |
memset(sclr, 0, ncs+1); |
179 |
return; |
180 |
} |
181 |
p = frexp(p, &i) * 256.0 / p; |
182 |
sclr[ncs] = i + COLXS; |
183 |
for (i = ncs; i--; ) |
184 |
sclr[i] = (scol[i] > 0) * (int)(scol[i]*p); |
185 |
} |
186 |
|
187 |
|
188 |
void |
189 |
scolr2scolor( /* common exponent to float spectrum */ |
190 |
SCOLOR scol, |
191 |
SCOLR sclr, |
192 |
int ncs |
193 |
) |
194 |
{ |
195 |
double f; |
196 |
int i; |
197 |
|
198 |
if (sclr[ncs] == 0) { |
199 |
memset(scol, 0, sizeof(COLORV)*ncs); |
200 |
return; |
201 |
} |
202 |
f = ldexp(1.0, (int)sclr[ncs]-(COLXS+8)); |
203 |
|
204 |
for (i = ncs; i--; ) |
205 |
scol[i] = (sclr[i] + 0.5)*f; |
206 |
} |
207 |
|
208 |
|
209 |
double |
210 |
scolor_mean( /* compute average for spectral color */ |
211 |
SCOLOR scol |
212 |
) |
213 |
{ |
214 |
int i = NCSAMP; |
215 |
double sum = 0; |
216 |
|
217 |
while (i--) |
218 |
sum += scol[i]; |
219 |
|
220 |
return sum/(double)NCSAMP; |
221 |
} |
222 |
|
223 |
|
224 |
double |
225 |
sintens( /* find maximum value from spectrum */ |
226 |
SCOLOR scol |
227 |
) |
228 |
{ |
229 |
int i = NCSAMP; |
230 |
COLORV peak = scol[--i]; |
231 |
|
232 |
while (i) |
233 |
if (scol[--i] > peak) |
234 |
peak = scol[i]; |
235 |
|
236 |
return peak; |
237 |
} |
238 |
|
239 |
|
240 |
void |
241 |
convertscolor( /* spectrum conversion, zero-fill ends */ |
242 |
SCOLOR dst, /* destination spectrum */ |
243 |
int dnc, /* destination # of spectral samples/intervals */ |
244 |
double dwl0, /* starting destination wavelength (longer) */ |
245 |
double dwl1, /* ending destination wavelength (shorter) */ |
246 |
const COLORV src[], /* source spectrum array */ |
247 |
int snc, |
248 |
double swl0, /* long/short wavelengths may be reversed */ |
249 |
double swl1 |
250 |
) |
251 |
{ |
252 |
const int sdir = 1 - 2*(swl0 < swl1); |
253 |
const double sstp = (swl1 - swl0)/(double)snc; |
254 |
const double dstp = (dwl1 - dwl0)/(double)dnc; |
255 |
const double rdstp = 1./dstp; |
256 |
int si, ssi, di; |
257 |
double wl; |
258 |
|
259 |
if ((dnc < 3) | (dwl0 <= dwl1) | (dst == src)) |
260 |
return; /* invalid destination */ |
261 |
|
262 |
if (dnc == snc && (dwl0-swl0)*(dwl0-swl0) + (dwl1-swl1)*(dwl1-swl1) <= .5) { |
263 |
memcpy(dst, src, sizeof(COLORV)*dnc); |
264 |
return; /* same spectral sampling */ |
265 |
} |
266 |
memset(dst, 0, sizeof(COLORV)*dnc); |
267 |
/* set starting positions */ |
268 |
if ((sdir>0 ? swl0 : swl1) <= dwl0) { |
269 |
if (sdir > 0) { |
270 |
wl = swl0; |
271 |
ssi = 0; |
272 |
} else { |
273 |
wl = swl1; |
274 |
ssi = snc-1; |
275 |
} |
276 |
si = 0; |
277 |
di = (wl - dwl0)*rdstp; |
278 |
} else { |
279 |
wl = dwl0; |
280 |
if (sdir > 0) { |
281 |
ssi = si = (wl - swl0)/sstp; |
282 |
} else { |
283 |
si = (wl - swl1)/sstp; |
284 |
ssi = snc-1 - si; |
285 |
} |
286 |
di = 0; |
287 |
} |
288 |
swl0 += (sdir < 0)*sstp; |
289 |
/* step through intervals */ |
290 |
while ((si < snc) & (di < dnc)) { |
291 |
double intvl; |
292 |
if (swl0 + (ssi+sdir)*sstp < dwl0 + (di+1)*dstp) { |
293 |
intvl = dwl0 + (di+1)*dstp - wl; |
294 |
dst[di++] += src[ssi]*intvl*rdstp; |
295 |
} else { |
296 |
intvl = swl0 + (ssi+sdir)*sstp - wl; |
297 |
dst[di] += src[ssi]*intvl*rdstp; |
298 |
ssi += sdir; |
299 |
si++; |
300 |
} |
301 |
wl += intvl; |
302 |
} |
303 |
} |
304 |
|
305 |
|
306 |
void * |
307 |
tempbuffer( /* get a temporary buffer */ |
308 |
size_t len |
309 |
) |
310 |
{ |
311 |
static void *tempbuf = NULL; |
312 |
static size_t tempbuflen = 0; |
313 |
|
314 |
if (!len) { /* call to free */ |
315 |
if (tempbuflen) { |
316 |
free(tempbuf); |
317 |
tempbuf = NULL; |
318 |
tempbuflen = 0; |
319 |
} |
320 |
return(NULL); |
321 |
} |
322 |
if (len <= tempbuflen) /* big enough already? */ |
323 |
return(tempbuf); |
324 |
/* else free & reallocate */ |
325 |
if (tempbuflen) |
326 |
free(tempbuf); |
327 |
tempbuf = malloc(len); |
328 |
tempbuflen = len*(tempbuf != NULL); |
329 |
return(tempbuf); |
330 |
} |
331 |
|
332 |
|
333 |
int |
334 |
fwritecolrs( /* write out a colr scanline */ |
335 |
COLR *scanline, |
336 |
int len, |
337 |
FILE *fp |
338 |
) |
339 |
{ |
340 |
int i, j, beg, cnt = 1; |
341 |
int c2; |
342 |
|
343 |
if ((len < MINELEN) | (len > MAXELEN)) /* OOBs, write out flat */ |
344 |
return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len); |
345 |
/* put magic header */ |
346 |
putc(2, fp); |
347 |
putc(2, fp); |
348 |
putc(len>>8, fp); |
349 |
putc(len&0xff, fp); |
350 |
/* put components seperately */ |
351 |
for (i = 0; i < 4; i++) { |
352 |
for (j = 0; j < len; j += cnt) { /* find next run */ |
353 |
for (beg = j; beg < len; beg += cnt) { |
354 |
for (cnt = 1; (cnt < 127) & (beg+cnt < len) && |
355 |
scanline[beg+cnt][i] == scanline[beg][i]; cnt++) |
356 |
; |
357 |
if (cnt >= MINRUN) |
358 |
break; /* long enough */ |
359 |
} |
360 |
if ((beg-j > 1) & (beg-j < MINRUN)) { |
361 |
c2 = j+1; |
362 |
while (scanline[c2++][i] == scanline[j][i]) |
363 |
if (c2 == beg) { /* short run */ |
364 |
putc(128+beg-j, fp); |
365 |
putc(scanline[j][i], fp); |
366 |
j = beg; |
367 |
break; |
368 |
} |
369 |
} |
370 |
while (j < beg) { /* write out non-run */ |
371 |
if ((c2 = beg-j) > 128) c2 = 128; |
372 |
putc(c2, fp); |
373 |
while (c2--) |
374 |
putc(scanline[j++][i], fp); |
375 |
} |
376 |
if (cnt >= MINRUN) { /* write out run */ |
377 |
putc(128+cnt, fp); |
378 |
putc(scanline[beg][i], fp); |
379 |
} else |
380 |
cnt = 0; |
381 |
} |
382 |
} |
383 |
return(ferror(fp) ? -1 : 0); |
384 |
} |
385 |
|
386 |
/* |
387 |
* An old-format scanline is either a stream of valid RGBE or XYZE real |
388 |
* pixels or at least one real pixel followed by some number of |
389 |
* invalid real pixels of the form (1,1,1,n), where n is a count. |
390 |
* These can themselves be repeated to create a multibyte repeat |
391 |
* count, with the least significant byte first (little-endian order.) |
392 |
* Repeat counts are limited by the size of an int; if a repetition |
393 |
* leads to an overrun, the rest of the the repetition will be |
394 |
* silently ignored. |
395 |
*/ |
396 |
static int |
397 |
oldreadcolrs( /* read in an old-style colr scanline */ |
398 |
COLR *scanline, |
399 |
int len, |
400 |
FILE *fp |
401 |
) |
402 |
{ |
403 |
int rshift = 0; |
404 |
int i; |
405 |
|
406 |
while (len > 0) { |
407 |
scanline[0][RED] = getc(fp); |
408 |
scanline[0][GRN] = getc(fp); |
409 |
scanline[0][BLU] = getc(fp); |
410 |
scanline[0][EXP] = i = getc(fp); |
411 |
if (i == EOF) |
412 |
return(-1); |
413 |
if (scanline[0][GRN] == 1 && |
414 |
(scanline[0][RED] == 1) & |
415 |
(scanline[0][BLU] == 1)) { |
416 |
i = scanline[0][EXP] << rshift; |
417 |
while (i--) { |
418 |
copycolr(scanline[0], scanline[-1]); |
419 |
if (--len <= 0) |
420 |
return(0); |
421 |
scanline++; |
422 |
} |
423 |
rshift += 8; |
424 |
} else { |
425 |
scanline++; |
426 |
len--; |
427 |
rshift = 0; |
428 |
} |
429 |
} |
430 |
return(0); |
431 |
} |
432 |
|
433 |
/* |
434 |
* There are two scanline formats: old and new. The old format |
435 |
* compresses runs of RGBE or XYZE four-byte real pixels; the new |
436 |
* format breaks the pixels into R, G, B, and E lines (or XYZE lines) |
437 |
* which are individually run-length encoded. |
438 |
* |
439 |
* An old-format scanline always begins with a valid real pixel; at |
440 |
* least one of the RGB (or XYZ) values will have its high-order bit |
441 |
* set. A new-format scanline begins with four bytes which are not a |
442 |
* valid real pixel: (2, 2, lenhigh, lenlow) where lenhigh is always |
443 |
* less than 128 and hence never has a high-order bit set. |
444 |
* |
445 |
* A new-format scanline is broken into its RGBE or XYZE components. |
446 |
* Each is output and run-length encoded separately so that a scanline |
447 |
* is broken into four records. In turn, each record is organized |
448 |
* into chunks of up to 128 characters, which begin with a count byte. |
449 |
* If the count byte is greater than 128, the following data byte is |
450 |
* repeated (count-128) times. If not, the count byte is followed by |
451 |
* that many data bytes. |
452 |
*/ |
453 |
int |
454 |
freadcolrs( /* read in an encoded colr scanline */ |
455 |
COLR *scanline, |
456 |
int len, |
457 |
FILE *fp |
458 |
) |
459 |
{ |
460 |
int i, j; |
461 |
int code, val; |
462 |
/* determine scanline type */ |
463 |
if (len <= 0) |
464 |
return(0); |
465 |
if ((i = getc(fp)) == EOF) |
466 |
return(-1); |
467 |
scanline[0][RED] = i; |
468 |
scanline[0][GRN] = getc(fp); |
469 |
scanline[0][BLU] = getc(fp); |
470 |
if ((i = getc(fp)) == EOF) |
471 |
return(-1); |
472 |
if ((scanline[0][RED] != 2) | (scanline[0][GRN] != 2) | |
473 |
(scanline[0][BLU] & 0x80)) { |
474 |
scanline[0][EXP] = i; |
475 |
return(oldreadcolrs(scanline+1, len-1, fp)); |
476 |
} |
477 |
if ((scanline[0][BLU]<<8 | i) != len) |
478 |
return(-1); /* length mismatch! */ |
479 |
/* read each component */ |
480 |
for (i = 0; i < 4; i++) |
481 |
for (j = 0; j < len; ) { |
482 |
if ((code = getc(fp)) == EOF) |
483 |
return(-1); |
484 |
if (code > 128) { /* run */ |
485 |
code &= 127; |
486 |
if ((val = getc(fp)) == EOF) |
487 |
return -1; |
488 |
if (j + code > len) |
489 |
return -1; /* overrun */ |
490 |
while (code--) |
491 |
scanline[j++][i] = val; |
492 |
} else { /* non-run */ |
493 |
if (j + code > len) |
494 |
return -1; /* overrun */ |
495 |
while (code--) { |
496 |
if ((val = getc(fp)) == EOF) |
497 |
return -1; |
498 |
scanline[j++][i] = val; |
499 |
} |
500 |
} |
501 |
} |
502 |
return(0); |
503 |
} |
504 |
|
505 |
|
506 |
/* read an nc-component common-exponent color scanline */ |
507 |
int |
508 |
freadscolrs(uby8 *scanline, int nc, int len, FILE *fp) |
509 |
{ |
510 |
if (nc < 3) |
511 |
return(-1); |
512 |
if (nc == 3) |
513 |
return(freadcolrs((COLR *)scanline, len, fp)); |
514 |
|
515 |
if (fread(scanline, nc+1, len, fp) != len) |
516 |
return(-1); |
517 |
return(0); |
518 |
} |
519 |
|
520 |
|
521 |
/* write an common-exponent spectral color scanline */ |
522 |
int |
523 |
fwritescolrs(uby8 *sscanline, int nc, int len, FILE *fp) |
524 |
{ |
525 |
if (nc < 3) |
526 |
return(-1); |
527 |
if (nc == 3) |
528 |
return(fwritecolrs((COLR *)sscanline, len, fp)); |
529 |
|
530 |
if (fwrite(sscanline, nc+1, len, fp) != len) |
531 |
return(-1); |
532 |
return(0); |
533 |
} |
534 |
|
535 |
|
536 |
int |
537 |
fwritescan( /* write out an RGB or XYZ scanline */ |
538 |
COLOR *scanline, |
539 |
int len, |
540 |
FILE *fp |
541 |
) |
542 |
{ |
543 |
COLR *clrscan; |
544 |
int n; |
545 |
COLR *sp; |
546 |
/* get scanline buffer */ |
547 |
if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
548 |
return(-1); |
549 |
clrscan = sp; |
550 |
/* convert scanline */ |
551 |
n = len; |
552 |
while (n-- > 0) { |
553 |
setcolr(sp[0], scanline[0][RED], |
554 |
scanline[0][GRN], |
555 |
scanline[0][BLU]); |
556 |
scanline++; |
557 |
sp++; |
558 |
} |
559 |
return(fwritecolrs(clrscan, len, fp)); |
560 |
} |
561 |
|
562 |
|
563 |
int |
564 |
freadscan( /* read in an RGB or XYZ scanline */ |
565 |
COLOR *scanline, |
566 |
int len, |
567 |
FILE *fp |
568 |
) |
569 |
{ |
570 |
COLR *clrscan; |
571 |
|
572 |
if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
573 |
return(-1); |
574 |
if (freadcolrs(clrscan, len, fp) < 0) |
575 |
return(-1); |
576 |
/* convert scanline */ |
577 |
colr_color(scanline[0], clrscan[0]); |
578 |
while (--len > 0) { |
579 |
scanline++; clrscan++; |
580 |
if (clrscan[0][GRN] == clrscan[-1][GRN] && |
581 |
(clrscan[0][RED] == clrscan[-1][RED]) & |
582 |
(clrscan[0][BLU] == clrscan[-1][BLU]) & |
583 |
(clrscan[0][EXP] == clrscan[-1][EXP])) |
584 |
copycolor(scanline[0], scanline[-1]); |
585 |
else |
586 |
colr_color(scanline[0], clrscan[0]); |
587 |
} |
588 |
return(0); |
589 |
} |
590 |
|
591 |
|
592 |
/* read an nc-component color scanline */ |
593 |
int |
594 |
freadsscan(COLORV *sscanline, int nc, int len, FILE *fp) |
595 |
{ |
596 |
uby8 *tscn = (uby8 *)tempbuffer((nc+1)*len); |
597 |
int i; |
598 |
|
599 |
if (tscn == NULL || freadscolrs(tscn, nc, len, fp) < 0) |
600 |
return(-1); |
601 |
for (i = len; i-- > 0; ) { |
602 |
scolr2scolor(sscanline, tscn, nc); |
603 |
sscanline += nc; |
604 |
tscn += nc+1; |
605 |
} |
606 |
return(0); |
607 |
} |
608 |
|
609 |
|
610 |
/* write an nc-component spectral color scanline */ |
611 |
int |
612 |
fwritesscan(COLORV *sscanline, int nc, int len, FILE *fp) |
613 |
{ |
614 |
uby8 *tscn = (uby8 *)tempbuffer((nc+1)*len); |
615 |
int i; |
616 |
|
617 |
if (tscn == NULL) |
618 |
return(-1); |
619 |
for (i = 0; i < len; i++) { |
620 |
scolor2scolr(tscn+i*(nc+1), sscanline, nc); |
621 |
sscanline += nc; |
622 |
} |
623 |
return(fwritescolrs(tscn, nc, len, fp)); |
624 |
} |
625 |
|
626 |
|
627 |
void |
628 |
setcolr( /* assign a short color value */ |
629 |
COLR clr, |
630 |
double r, |
631 |
double g, |
632 |
double b |
633 |
) |
634 |
{ |
635 |
double d; |
636 |
int e; |
637 |
|
638 |
d = r > g ? r : g; |
639 |
if (b > d) d = b; |
640 |
|
641 |
if (d <= 1e-32) { |
642 |
clr[RED] = clr[GRN] = clr[BLU] = 0; |
643 |
clr[EXP] = 0; |
644 |
return; |
645 |
} |
646 |
|
647 |
d = frexp(d, &e) * 256.0 / d; |
648 |
|
649 |
clr[RED] = (r > 0) * (int)(r*d); |
650 |
clr[GRN] = (g > 0) * (int)(g*d); |
651 |
clr[BLU] = (b > 0) * (int)(b*d); |
652 |
clr[EXP] = e + COLXS; |
653 |
} |
654 |
|
655 |
|
656 |
void |
657 |
colr_color( /* convert short to float color */ |
658 |
COLOR col, |
659 |
COLR clr |
660 |
) |
661 |
{ |
662 |
double f; |
663 |
|
664 |
if (clr[EXP] == 0) { |
665 |
col[RED] = col[GRN] = col[BLU] = 0.0; |
666 |
return; |
667 |
} |
668 |
f = ldexp(1.0, (int)clr[EXP]-(COLXS+8)); |
669 |
col[RED] = (clr[RED] + 0.5)*f; |
670 |
col[GRN] = (clr[GRN] + 0.5)*f; |
671 |
col[BLU] = (clr[BLU] + 0.5)*f; |
672 |
} |
673 |
|
674 |
|
675 |
int |
676 |
bigdiff( /* c1 delta c2 > md? */ |
677 |
COLOR c1, |
678 |
COLOR c2, |
679 |
double md |
680 |
) |
681 |
{ |
682 |
int i; |
683 |
|
684 |
for (i = 0; i < 3; i++) |
685 |
if ((colval(c1,i)-colval(c2,i) > md*colval(c2,i)) | |
686 |
(colval(c2,i)-colval(c1,i) > md*colval(c1,i))) |
687 |
return(1); |
688 |
return(0); |
689 |
} |
690 |
|
691 |
|
692 |
int |
693 |
sbigsdiff( /* sc1 delta sc2 > md? */ |
694 |
SCOLOR c1, |
695 |
SCOLOR c2, |
696 |
double md |
697 |
) |
698 |
{ |
699 |
int i = NCSAMP; |
700 |
|
701 |
while (i--) |
702 |
if ((c1[i]-c2[i] > md*c2[i]) | (c2[i]-c1[i] > md*c1[i])) |
703 |
return(1); |
704 |
return(0); |
705 |
} |