| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: color.c,v 2.31 2023/11/27 21:00:14 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 |
|
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|
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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) |
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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) |
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return(-1); /* also reject */ |
| 53 |
|
| 54 |
if (cn[3] > MAXCSAMP) |
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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? */ |
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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--; ) { |
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const float cwl = (i+.5f)/cn[3]*(wlpt[3]-wlpt[0]) + wlpt[0]; |
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for (j = 3; j--; ) |
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if (fabs(cwl - PKWL[j]) < fabs(curwl[j] - PKWL[j])) { |
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curwl[j] = cwl; |
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cn[j] = i; |
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} |
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} |
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} |
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return(1); /* happy return value */ |
| 80 |
} |
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|
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|
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void |
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setscolor( /* assign spectral color from RGB */ |
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SCOLOR scol, |
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double r, |
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double g, |
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double b |
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) |
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{ |
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const double step = (WLPART[3] - WLPART[0])/(double)NCSAMP; |
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double cwl = WLPART[0] + .5*step; |
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int i; |
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|
| 95 |
for (i = 0; i < NCSAMP; i++) { |
| 96 |
if (cwl >= WLPART[1]) |
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scol[i] = r; |
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else if (cwl >= WLPART[2]) |
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scol[i] = g; |
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else |
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scol[i] = b; |
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cwl += step; |
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} |
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} |
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|
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|
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void |
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scolor2color( /* assign RGB color from spectrum */ |
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COLOR col, |
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SCOLOR scol, /* uses average over bands */ |
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int ncs, |
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const float wlpt[4] |
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) |
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{ |
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const double step = (wlpt[3] - wlpt[0])/(double)ncs; |
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double cwl = wlpt[0] + .5*step; |
| 117 |
int i, j=0, n=0; |
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|
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setcolor(col, 0, 0, 0); |
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for (i = 0; i < ncs; i++) { |
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if (cwl < wlpt[j+1]) { |
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if (n > 1) col[j] /= (COLORV)n; |
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j++; |
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n = 0; |
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} |
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col[j] += scol[i]; |
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n++; |
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cwl += step; |
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} |
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if (n > 1) col[j] /= (COLORV)n; |
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} |
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|
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|
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void |
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scolor2colr( /* assign RGBE from spectral color */ |
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COLR clr, |
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SCOLOR scol, /* uses average over bands */ |
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int ncs, |
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const float wlpt[4] |
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) |
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{ |
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COLOR col; |
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|
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scolor2color(col, scol, ncs, wlpt); |
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setcolr(clr, col[RED], col[GRN], col[BLU]); |
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} |
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|
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|
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void |
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scolor2scolr( /* float spectrum to common exponent */ |
| 151 |
SCOLR sclr, |
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SCOLOR scol, |
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int ncs |
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) |
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{ |
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int i = ncs; |
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COLORV p = scol[--i]; |
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|
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while (i) |
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if (scol[--i] > p) |
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p = scol[i]; |
| 162 |
if (p <= 1e-32) { |
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memset(sclr, 0, ncs+1); |
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return; |
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} |
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p = frexp(p, &i) * 256.0 / p; |
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sclr[ncs] = i + COLXS; |
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for (i = ncs; i--; ) |
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sclr[i] = (scol[i] > 0) * (int)(scol[i]*p); |
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} |
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|
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|
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void |
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scolr2scolor( /* common exponent to float spectrum */ |
| 175 |
SCOLOR scol, |
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SCOLR sclr, |
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int ncs |
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) |
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{ |
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double f; |
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int i; |
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|
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if (sclr[ncs] == 0) { |
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memset(scol, 0, sizeof(COLORV)*ncs); |
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return; |
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} |
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f = ldexp(1.0, (int)sclr[ncs]-(COLXS+8)); |
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|
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for (i = ncs; i--; ) |
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scol[i] = (sclr[i] + 0.5)*f; |
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} |
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|
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|
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double |
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scolor_mean( /* compute average for spectral color */ |
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SCOLOR scol |
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) |
| 198 |
{ |
| 199 |
int i = NCSAMP; |
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double sum = 0; |
| 201 |
|
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while (i--) |
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sum += scol[i]; |
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|
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return sum/(double)NCSAMP; |
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} |
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|
| 208 |
|
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double |
| 210 |
sintens( /* find maximum value from spectrum */ |
| 211 |
SCOLOR scol |
| 212 |
) |
| 213 |
{ |
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int i = NCSAMP; |
| 215 |
COLORV peak = scol[--i]; |
| 216 |
|
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while (i) |
| 218 |
if (scol[--i] > peak) |
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peak = scol[i]; |
| 220 |
|
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return peak; |
| 222 |
} |
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|
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|
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void |
| 226 |
convertscolor( /* spectrum conversion, zero-fill ends */ |
| 227 |
SCOLOR dst, /* destination spectrum */ |
| 228 |
int dnc, /* destination # of spectral samples/intervals */ |
| 229 |
double dwl0, /* starting destination wavelength (longer) */ |
| 230 |
double dwl1, /* ending destination wavelength (shorter) */ |
| 231 |
const COLORV src[], /* source spectrum array */ |
| 232 |
int snc, |
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double swl0, /* long/short wavelengths may be reversed */ |
| 234 |
double swl1 |
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) |
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{ |
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const int sdir = 1 - 2*(swl0 < swl1); |
| 238 |
const double sstp = (swl1 - swl0)/(double)snc; |
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const double dstp = (dwl1 - dwl0)/(double)dnc; |
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const double rdstp = 1./dstp; |
| 241 |
int si, ssi, di; |
| 242 |
double wl; |
| 243 |
|
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if ((dnc < 3) | (dwl0 <= dwl1) | (dst == src)) |
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return; /* invalid destination */ |
| 246 |
|
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if (dnc == snc && (dwl0-swl0)*(dwl0-swl0) + (dwl1-swl1)*(dwl1-swl1) <= .5) { |
| 248 |
memcpy(dst, src, sizeof(COLORV)*dnc); |
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return; /* same spectral sampling */ |
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} |
| 251 |
memset(dst, 0, sizeof(COLORV)*dnc); |
| 252 |
/* set starting positions */ |
| 253 |
if ((sdir>0 ? swl0 : swl1) <= dwl0) { |
| 254 |
if (sdir > 0) { |
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wl = swl0; |
| 256 |
ssi = 0; |
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} else { |
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wl = swl1; |
| 259 |
ssi = snc-1; |
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} |
| 261 |
si = 0; |
| 262 |
di = (wl - dwl0)*rdstp; |
| 263 |
} else { |
| 264 |
wl = dwl0; |
| 265 |
if (sdir > 0) { |
| 266 |
ssi = si = (wl - swl0)/sstp; |
| 267 |
} else { |
| 268 |
si = (wl - swl1)/sstp; |
| 269 |
ssi = snc-1 - si; |
| 270 |
} |
| 271 |
di = 0; |
| 272 |
} |
| 273 |
swl0 += (sdir < 0)*sstp; |
| 274 |
/* step through intervals */ |
| 275 |
while ((si < snc) & (di < dnc)) { |
| 276 |
double intvl; |
| 277 |
if (swl0 + (ssi+sdir)*sstp < dwl0 + (di+1)*dstp) { |
| 278 |
intvl = dwl0 + (di+1)*dstp - wl; |
| 279 |
dst[di++] += src[ssi]*intvl*rdstp; |
| 280 |
} else { |
| 281 |
intvl = swl0 + (ssi+sdir)*sstp - wl; |
| 282 |
dst[di] += src[ssi]*intvl*rdstp; |
| 283 |
ssi += sdir; |
| 284 |
si++; |
| 285 |
} |
| 286 |
wl += intvl; |
| 287 |
} |
| 288 |
} |
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|
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|
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void * |
| 292 |
tempbuffer( /* get a temporary buffer */ |
| 293 |
size_t len |
| 294 |
) |
| 295 |
{ |
| 296 |
static void *tempbuf = NULL; |
| 297 |
static size_t tempbuflen = 0; |
| 298 |
|
| 299 |
if (!len) { /* call to free */ |
| 300 |
if (tempbuflen) { |
| 301 |
free(tempbuf); |
| 302 |
tempbuf = NULL; |
| 303 |
tempbuflen = 0; |
| 304 |
} |
| 305 |
return(NULL); |
| 306 |
} |
| 307 |
if (len <= tempbuflen) /* big enough already? */ |
| 308 |
return(tempbuf); |
| 309 |
/* else free & reallocate */ |
| 310 |
if (tempbuflen) |
| 311 |
free(tempbuf); |
| 312 |
tempbuf = malloc(len); |
| 313 |
tempbuflen = len*(tempbuf != NULL); |
| 314 |
return(tempbuf); |
| 315 |
} |
| 316 |
|
| 317 |
|
| 318 |
int |
| 319 |
fwritecolrs( /* write out a colr scanline */ |
| 320 |
COLR *scanline, |
| 321 |
int len, |
| 322 |
FILE *fp |
| 323 |
) |
| 324 |
{ |
| 325 |
int i, j, beg, cnt = 1; |
| 326 |
int c2; |
| 327 |
|
| 328 |
if ((len < MINELEN) | (len > MAXELEN)) /* OOBs, write out flat */ |
| 329 |
return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len); |
| 330 |
/* put magic header */ |
| 331 |
putc(2, fp); |
| 332 |
putc(2, fp); |
| 333 |
putc(len>>8, fp); |
| 334 |
putc(len&0xff, fp); |
| 335 |
/* put components seperately */ |
| 336 |
for (i = 0; i < 4; i++) { |
| 337 |
for (j = 0; j < len; j += cnt) { /* find next run */ |
| 338 |
for (beg = j; beg < len; beg += cnt) { |
| 339 |
for (cnt = 1; (cnt < 127) & (beg+cnt < len) && |
| 340 |
scanline[beg+cnt][i] == scanline[beg][i]; cnt++) |
| 341 |
; |
| 342 |
if (cnt >= MINRUN) |
| 343 |
break; /* long enough */ |
| 344 |
} |
| 345 |
if ((beg-j > 1) & (beg-j < MINRUN)) { |
| 346 |
c2 = j+1; |
| 347 |
while (scanline[c2++][i] == scanline[j][i]) |
| 348 |
if (c2 == beg) { /* short run */ |
| 349 |
putc(128+beg-j, fp); |
| 350 |
putc(scanline[j][i], fp); |
| 351 |
j = beg; |
| 352 |
break; |
| 353 |
} |
| 354 |
} |
| 355 |
while (j < beg) { /* write out non-run */ |
| 356 |
if ((c2 = beg-j) > 128) c2 = 128; |
| 357 |
putc(c2, fp); |
| 358 |
while (c2--) |
| 359 |
putc(scanline[j++][i], fp); |
| 360 |
} |
| 361 |
if (cnt >= MINRUN) { /* write out run */ |
| 362 |
putc(128+cnt, fp); |
| 363 |
putc(scanline[beg][i], fp); |
| 364 |
} else |
| 365 |
cnt = 0; |
| 366 |
} |
| 367 |
} |
| 368 |
return(ferror(fp) ? -1 : 0); |
| 369 |
} |
| 370 |
|
| 371 |
/* |
| 372 |
* An old-format scanline is either a stream of valid RGBE or XYZE real |
| 373 |
* pixels or at least one real pixel followed by some number of |
| 374 |
* invalid real pixels of the form (1,1,1,n), where n is a count. |
| 375 |
* These can themselves be repeated to create a multibyte repeat |
| 376 |
* count, with the least significant byte first (little-endian order.) |
| 377 |
* Repeat counts are limited by the size of an int; if a repetition |
| 378 |
* leads to an overrun, the rest of the the repetition will be |
| 379 |
* silently ignored. |
| 380 |
*/ |
| 381 |
static int |
| 382 |
oldreadcolrs( /* read in an old-style colr scanline */ |
| 383 |
COLR *scanline, |
| 384 |
int len, |
| 385 |
FILE *fp |
| 386 |
) |
| 387 |
{ |
| 388 |
int rshift = 0; |
| 389 |
int i; |
| 390 |
|
| 391 |
while (len > 0) { |
| 392 |
scanline[0][RED] = getc(fp); |
| 393 |
scanline[0][GRN] = getc(fp); |
| 394 |
scanline[0][BLU] = getc(fp); |
| 395 |
scanline[0][EXP] = i = getc(fp); |
| 396 |
if (i == EOF) |
| 397 |
return(-1); |
| 398 |
if (scanline[0][GRN] == 1 && |
| 399 |
(scanline[0][RED] == 1) & |
| 400 |
(scanline[0][BLU] == 1)) { |
| 401 |
i = scanline[0][EXP] << rshift; |
| 402 |
while (i--) { |
| 403 |
copycolr(scanline[0], scanline[-1]); |
| 404 |
if (--len <= 0) |
| 405 |
return(0); |
| 406 |
scanline++; |
| 407 |
} |
| 408 |
rshift += 8; |
| 409 |
} else { |
| 410 |
scanline++; |
| 411 |
len--; |
| 412 |
rshift = 0; |
| 413 |
} |
| 414 |
} |
| 415 |
return(0); |
| 416 |
} |
| 417 |
|
| 418 |
/* |
| 419 |
* There are two scanline formats: old and new. The old format |
| 420 |
* compresses runs of RGBE or XYZE four-byte real pixels; the new |
| 421 |
* format breaks the pixels into R, G, B, and E lines (or XYZE lines) |
| 422 |
* which are individually run-length encoded. |
| 423 |
* |
| 424 |
* An old-format scanline always begins with a valid real pixel; at |
| 425 |
* least one of the RGB (or XYZ) values will have its high-order bit |
| 426 |
* set. A new-format scanline begins with four bytes which are not a |
| 427 |
* valid real pixel: (2, 2, lenhigh, lenlow) where lenhigh is always |
| 428 |
* less than 128 and hence never has a high-order bit set. |
| 429 |
* |
| 430 |
* A new-format scanline is broken into its RGBE or XYZE components. |
| 431 |
* Each is output and run-length encoded separately so that a scanline |
| 432 |
* is broken into four records. In turn, each record is organized |
| 433 |
* into chunks of up to 128 characters, which begin with a count byte. |
| 434 |
* If the count byte is greater than 128, the following data byte is |
| 435 |
* repeated (count-128) times. If not, the count byte is followed by |
| 436 |
* that many data bytes. |
| 437 |
*/ |
| 438 |
int |
| 439 |
freadcolrs( /* read in an encoded colr scanline */ |
| 440 |
COLR *scanline, |
| 441 |
int len, |
| 442 |
FILE *fp |
| 443 |
) |
| 444 |
{ |
| 445 |
int i, j; |
| 446 |
int code, val; |
| 447 |
/* determine scanline type */ |
| 448 |
if (len <= 0) |
| 449 |
return(0); |
| 450 |
if ((i = getc(fp)) == EOF) |
| 451 |
return(-1); |
| 452 |
scanline[0][RED] = i; |
| 453 |
scanline[0][GRN] = getc(fp); |
| 454 |
scanline[0][BLU] = getc(fp); |
| 455 |
if ((i = getc(fp)) == EOF) |
| 456 |
return(-1); |
| 457 |
if ((scanline[0][RED] != 2) | (scanline[0][GRN] != 2) | |
| 458 |
(scanline[0][BLU] & 0x80)) { |
| 459 |
scanline[0][EXP] = i; |
| 460 |
return(oldreadcolrs(scanline+1, len-1, fp)); |
| 461 |
} |
| 462 |
if ((scanline[0][BLU]<<8 | i) != len) |
| 463 |
return(-1); /* length mismatch! */ |
| 464 |
/* read each component */ |
| 465 |
for (i = 0; i < 4; i++) |
| 466 |
for (j = 0; j < len; ) { |
| 467 |
if ((code = getc(fp)) == EOF) |
| 468 |
return(-1); |
| 469 |
if (code > 128) { /* run */ |
| 470 |
code &= 127; |
| 471 |
if ((val = getc(fp)) == EOF) |
| 472 |
return -1; |
| 473 |
if (j + code > len) |
| 474 |
return -1; /* overrun */ |
| 475 |
while (code--) |
| 476 |
scanline[j++][i] = val; |
| 477 |
} else { /* non-run */ |
| 478 |
if (j + code > len) |
| 479 |
return -1; /* overrun */ |
| 480 |
while (code--) { |
| 481 |
if ((val = getc(fp)) == EOF) |
| 482 |
return -1; |
| 483 |
scanline[j++][i] = val; |
| 484 |
} |
| 485 |
} |
| 486 |
} |
| 487 |
return(0); |
| 488 |
} |
| 489 |
|
| 490 |
|
| 491 |
/* read an nc-component common-exponent color scanline */ |
| 492 |
int |
| 493 |
freadscolrs(uby8 *scanline, int nc, int len, FILE *fp) |
| 494 |
{ |
| 495 |
if (nc < 3) |
| 496 |
return(-1); |
| 497 |
if (nc == 3) |
| 498 |
return(freadcolrs((COLR *)scanline, len, fp)); |
| 499 |
|
| 500 |
if (fread(scanline, nc+1, len, fp) != len) |
| 501 |
return(-1); |
| 502 |
return(0); |
| 503 |
} |
| 504 |
|
| 505 |
|
| 506 |
/* write an common-exponent spectral color scanline */ |
| 507 |
int |
| 508 |
fwritescolrs(uby8 *sscanline, int nc, int len, FILE *fp) |
| 509 |
{ |
| 510 |
if (nc < 3) |
| 511 |
return(-1); |
| 512 |
if (nc == 3) |
| 513 |
return(fwritecolrs((COLR *)sscanline, len, fp)); |
| 514 |
|
| 515 |
if (fwrite(sscanline, nc+1, len, fp) != len) |
| 516 |
return(-1); |
| 517 |
return(0); |
| 518 |
} |
| 519 |
|
| 520 |
|
| 521 |
int |
| 522 |
fwritescan( /* write out an RGB or XYZ scanline */ |
| 523 |
COLOR *scanline, |
| 524 |
int len, |
| 525 |
FILE *fp |
| 526 |
) |
| 527 |
{ |
| 528 |
COLR *clrscan; |
| 529 |
int n; |
| 530 |
COLR *sp; |
| 531 |
/* get scanline buffer */ |
| 532 |
if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
| 533 |
return(-1); |
| 534 |
clrscan = sp; |
| 535 |
/* convert scanline */ |
| 536 |
n = len; |
| 537 |
while (n-- > 0) { |
| 538 |
setcolr(sp[0], scanline[0][RED], |
| 539 |
scanline[0][GRN], |
| 540 |
scanline[0][BLU]); |
| 541 |
scanline++; |
| 542 |
sp++; |
| 543 |
} |
| 544 |
return(fwritecolrs(clrscan, len, fp)); |
| 545 |
} |
| 546 |
|
| 547 |
|
| 548 |
int |
| 549 |
freadscan( /* read in an RGB or XYZ scanline */ |
| 550 |
COLOR *scanline, |
| 551 |
int len, |
| 552 |
FILE *fp |
| 553 |
) |
| 554 |
{ |
| 555 |
COLR *clrscan; |
| 556 |
|
| 557 |
if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
| 558 |
return(-1); |
| 559 |
if (freadcolrs(clrscan, len, fp) < 0) |
| 560 |
return(-1); |
| 561 |
/* convert scanline */ |
| 562 |
colr_color(scanline[0], clrscan[0]); |
| 563 |
while (--len > 0) { |
| 564 |
scanline++; clrscan++; |
| 565 |
if (clrscan[0][GRN] == clrscan[-1][GRN] && |
| 566 |
(clrscan[0][RED] == clrscan[-1][RED]) & |
| 567 |
(clrscan[0][BLU] == clrscan[-1][BLU]) & |
| 568 |
(clrscan[0][EXP] == clrscan[-1][EXP])) |
| 569 |
copycolor(scanline[0], scanline[-1]); |
| 570 |
else |
| 571 |
colr_color(scanline[0], clrscan[0]); |
| 572 |
} |
| 573 |
return(0); |
| 574 |
} |
| 575 |
|
| 576 |
|
| 577 |
/* read an nc-component color scanline */ |
| 578 |
int |
| 579 |
freadsscan(COLORV *sscanline, int nc, int len, FILE *fp) |
| 580 |
{ |
| 581 |
uby8 *tscn = (uby8 *)tempbuffer((nc+1)*len); |
| 582 |
int i; |
| 583 |
|
| 584 |
if (tscn == NULL || freadscolrs(tscn, nc, len, fp) < 0) |
| 585 |
return(-1); |
| 586 |
for (i = len; i-- > 0; ) { |
| 587 |
scolr2scolor(sscanline, tscn, nc); |
| 588 |
sscanline += nc; |
| 589 |
tscn += nc+1; |
| 590 |
} |
| 591 |
return(0); |
| 592 |
} |
| 593 |
|
| 594 |
|
| 595 |
/* write an nc-component spectral color scanline */ |
| 596 |
int |
| 597 |
fwritesscan(COLORV *sscanline, int nc, int len, FILE *fp) |
| 598 |
{ |
| 599 |
uby8 *tscn = (uby8 *)tempbuffer((nc+1)*len); |
| 600 |
int i; |
| 601 |
|
| 602 |
if (tscn == NULL) |
| 603 |
return(-1); |
| 604 |
for (i = 0; i < len; i++) { |
| 605 |
scolor2scolr(tscn+i*(nc+1), sscanline, nc); |
| 606 |
sscanline += nc; |
| 607 |
} |
| 608 |
return(fwritescolrs(tscn, nc, len, fp)); |
| 609 |
} |
| 610 |
|
| 611 |
|
| 612 |
void |
| 613 |
setcolr( /* assign a short color value */ |
| 614 |
COLR clr, |
| 615 |
double r, |
| 616 |
double g, |
| 617 |
double b |
| 618 |
) |
| 619 |
{ |
| 620 |
double d; |
| 621 |
int e; |
| 622 |
|
| 623 |
d = r > g ? r : g; |
| 624 |
if (b > d) d = b; |
| 625 |
|
| 626 |
if (d <= 1e-32) { |
| 627 |
clr[RED] = clr[GRN] = clr[BLU] = 0; |
| 628 |
clr[EXP] = 0; |
| 629 |
return; |
| 630 |
} |
| 631 |
|
| 632 |
d = frexp(d, &e) * 256.0 / d; |
| 633 |
|
| 634 |
clr[RED] = (r > 0) * (int)(r*d); |
| 635 |
clr[GRN] = (g > 0) * (int)(g*d); |
| 636 |
clr[BLU] = (b > 0) * (int)(b*d); |
| 637 |
clr[EXP] = e + COLXS; |
| 638 |
} |
| 639 |
|
| 640 |
|
| 641 |
void |
| 642 |
colr_color( /* convert short to float color */ |
| 643 |
COLOR col, |
| 644 |
COLR clr |
| 645 |
) |
| 646 |
{ |
| 647 |
double f; |
| 648 |
|
| 649 |
if (clr[EXP] == 0) { |
| 650 |
col[RED] = col[GRN] = col[BLU] = 0.0; |
| 651 |
return; |
| 652 |
} |
| 653 |
f = ldexp(1.0, (int)clr[EXP]-(COLXS+8)); |
| 654 |
col[RED] = (clr[RED] + 0.5)*f; |
| 655 |
col[GRN] = (clr[GRN] + 0.5)*f; |
| 656 |
col[BLU] = (clr[BLU] + 0.5)*f; |
| 657 |
} |
| 658 |
|
| 659 |
|
| 660 |
int |
| 661 |
bigdiff( /* c1 delta c2 > md? */ |
| 662 |
COLOR c1, |
| 663 |
COLOR c2, |
| 664 |
double md |
| 665 |
) |
| 666 |
{ |
| 667 |
int i; |
| 668 |
|
| 669 |
for (i = 0; i < 3; i++) |
| 670 |
if ((colval(c1,i)-colval(c2,i) > md*colval(c2,i)) | |
| 671 |
(colval(c2,i)-colval(c1,i) > md*colval(c1,i))) |
| 672 |
return(1); |
| 673 |
return(0); |
| 674 |
} |
| 675 |
|
| 676 |
|
| 677 |
int |
| 678 |
sbigsdiff( /* sc1 delta sc2 > md? */ |
| 679 |
SCOLOR c1, |
| 680 |
SCOLOR c2, |
| 681 |
double md |
| 682 |
) |
| 683 |
{ |
| 684 |
int i = NCSAMP; |
| 685 |
|
| 686 |
while (i--) |
| 687 |
if ((c1[i]-c2[i] > md*c2[i]) | (c2[i]-c1[i] > md*c1[i])) |
| 688 |
return(1); |
| 689 |
return(0); |
| 690 |
} |
