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#ifndef lint |
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static const char RCSid[] = "$Id: tmap16bit.c,v 1.8 2008/05/15 22:15:16 greg Exp $"; |
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#endif |
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/* |
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* Routines for tone-mapping 16-bit/primary pixels |
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* |
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* Externals declared in tonemap.h |
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*/ |
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|
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#include "copyright.h" |
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|
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#include <stdio.h> |
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#include <math.h> |
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#include "tmprivat.h" |
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|
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#define LOGTABBITS 11 /* log table is 1<<LOGTABBITS long */ |
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#define GAMTABBITS 9 /* gamma table is 1<<GAMTABBITS long */ |
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#define MONGAMTSZ 1024 /* monitor gamma table length */ |
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|
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static float logtab[1<<LOGTABBITS]; |
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static float gamtab[1<<GAMTABBITS]; |
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static float gammul[16]; |
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static double cur_gam = 0.; |
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static BYTE mongamtab[MONGAMTSZ]; |
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static double cur_mongam = 0.; |
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|
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#define imultpow2(i,s) ((s)>=0 ? (i)<<(s) : (i)>>-(s)) |
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|
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|
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/* Fill our log table */ |
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static void |
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mkLogTable() |
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{ |
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int i; |
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|
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if (logtab[0] != 0.f) |
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return; |
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for (i = 1<<LOGTABBITS; i--; ) |
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logtab[i] = log(imultpow2(i,15-LOGTABBITS)*(1./(1L<<16)) |
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+ .5); |
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} |
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|
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|
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/* Fill our input gamma table */ |
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static void |
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mkGamTable(double gv) |
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{ |
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int i; |
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|
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if (gv == cur_gam) |
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return; |
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for (i = 1<<GAMTABBITS; i--; ) |
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gamtab[i] = pow((i+.5)*(1./(1<<GAMTABBITS)), gv); |
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for (i = 16; i--; ) |
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gammul[i] = pow((double)(1L<<i), -gv); |
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cur_gam = gv; |
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} |
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|
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|
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/* Fill our monitor gamma table */ |
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static void |
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mkMonGamTable(TMstruct *tms) |
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{ |
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int i; |
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|
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if (tms->mongam == cur_mongam) |
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return; |
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for (i = MONGAMTSZ; i--; ) |
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mongamtab[i] = 256.*pow((i+.5)*(1./MONGAMTSZ), 1./tms->mongam); |
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cur_mongam = tms->mongam; |
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} |
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|
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|
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/* Find normalizing shift value for a 2-byte unsigned integer */ |
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static int |
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normShift16(int i) |
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{ |
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int s = 0; |
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|
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if (!i) |
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return(-1); |
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while (!(i & 0x8000)) { |
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i <<= 1; |
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++s; |
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} |
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return(s); |
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} |
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|
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|
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/* Find common normalizing shift for 3 2-byte unsigned integers */ |
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static int |
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normShift48(uint16 clr48[3]) |
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{ |
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int imax = (clr48[1] > clr48[0] ? clr48[1] : clr48[0]); |
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if (clr48[2] > imax) |
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imax = clr48[2]; |
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return(normShift16(imax)); |
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} |
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|
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|
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/* convert at 48-bit tristimulus value to a COLOR */ |
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static void |
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rgb48_color(COLOR col, uint16 clr48[3], double gv) |
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{ |
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int nshft; |
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|
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if (gv == 1.) { /* linear case */ |
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col[0] = clr48[0]*(1./(1L<<16)); |
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col[1] = clr48[1]*(1./(1L<<16)); |
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col[2] = clr48[2]*(1./(1L<<16)); |
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return; |
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} |
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/* non-linear case */ |
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/* XXX Uncomment if this routine is made public |
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if (gv != cur_gam) |
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mkGamTable(gv); |
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*/ |
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nshft = normShift48(clr48); |
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if (nshft < 0) { |
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col[0] = col[1] = col[2] = .0f; |
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return; |
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} |
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col[0] = gamtab[imultpow2(clr48[0],GAMTABBITS-16+nshft)] * |
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gammul[nshft]; |
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col[1] = gamtab[imultpow2(clr48[1],GAMTABBITS-16+nshft)] * |
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gammul[nshft]; |
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col[2] = gamtab[imultpow2(clr48[2],GAMTABBITS-16+nshft)] * |
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gammul[nshft]; |
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} |
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|
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|
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/* Convert 16-bit gray scanline to encoded luminance */ |
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int |
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tmCvGray16(TMstruct *tms, TMbright *ls, uint16 *scan, int len, double gv) |
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{ |
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static const char funcName[] = "tmCvGray16"; |
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static double cur_inpsf = 1.; |
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static double log_inpsf = 0.; |
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int nshft; |
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double d; |
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|
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if (tms == NULL) |
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returnErr(TM_E_TMINVAL); |
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if ((ls == NULL) | (scan == NULL) | (len < 0)) |
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returnErr(TM_E_ILLEGAL); |
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if (gv <= 0.) |
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gv = DEFGAM; |
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/* initialize log table */ |
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if (logtab[0] == 0.f) |
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mkLogTable(); |
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if (cur_inpsf != tms->inpsf) |
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log_inpsf = log(cur_inpsf = tms->inpsf); |
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/* convert 16-bit grays */ |
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while (len--) { |
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nshft = normShift16(*scan); |
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if (nshft < 0) { /* bogus value */ |
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*ls++ = TM_NOBRT; |
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scan++; |
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continue; |
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} |
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d = logtab[ imultpow2(*scan,LOGTABBITS-15+nshft) & |
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((1L<<LOGTABBITS)-1) ]; |
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d -= M_LN2*nshft; |
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d = (double)TM_BRTSCALE * (gv*d + log_inpsf); |
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*ls++ = (d>0. ? d+.5 : d-.5); |
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scan++; |
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} |
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returnOK; |
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} |
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|
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/* Convert a 48-bit RGB scanline to encoded luminance/chrominance */ |
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int |
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tmCvRGB48(TMstruct *tms, TMbright *ls, BYTE *cs, |
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uint16 (*scan)[3], int len, double gv) |
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{ |
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static const char funcName[] = "tmCvRGB48"; |
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static double cur_inpsf = 1.; |
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static double log_inpsf = 0.; |
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int i; |
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|
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if (tms == NULL) |
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returnErr(TM_E_TMINVAL); |
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if ((ls == NULL) | (scan == NULL) | (len < 0)) |
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returnErr(TM_E_ILLEGAL); |
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if (gv <= 0.) |
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gv = DEFGAM; |
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/* sync input gamma table */ |
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if (gv != cur_gam) |
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mkGamTable(gv); |
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if (tmNeedMatrix(tms)) { /* need floating point */ |
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COLOR *newscan; |
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newscan = (COLOR *)tempbuffer(len*sizeof(COLOR)); |
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if (newscan == NULL) |
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returnErr(TM_E_NOMEM); |
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for (i = len; i--; ) |
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rgb48_color(newscan[i], scan[i], gv); |
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return(tmCvColors(tms, ls, cs, newscan, len)); |
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} |
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/* sync monitor gamma table */ |
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if (cs != TM_NOCHROM && tms->mongam != cur_mongam) |
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mkMonGamTable(tms); |
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/* initialize log table */ |
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if (logtab[0] == 0.f) |
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mkLogTable(); |
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if (cur_inpsf != tms->inpsf) |
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log_inpsf = log(cur_inpsf = tms->inpsf); |
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if (tms->flags & TM_F_MESOPIC) |
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tmMkMesofact(); |
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/* convert scanline */ |
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for (i = len; i--; ) { |
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int nshft = normShift48(scan[i]); |
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COLOR cmon; |
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double lum; |
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int bi; |
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|
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if (nshft < 0) { |
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bi = TM_NOBRT; /* bogus value */ |
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lum = 1.; |
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setcolor(cmon, 1., 1., 1.); |
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} else { |
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int j = GAMTABBITS-16+nshft; |
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int nshft2; |
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double d; |
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/* normalized linear */ |
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setcolor(cmon, gamtab[imultpow2(scan[i][0],j)], |
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gamtab[imultpow2(scan[i][1],j)], |
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gamtab[imultpow2(scan[i][2],j)] ); |
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lum = tms->clf[RED]*cmon[RED]; |
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lum += tms->clf[GRN]*cmon[GRN]; |
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lum += tms->clf[BLU]*cmon[BLU]; |
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/* convert to log Y */ |
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j = lum * (double)(1L<<16); |
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nshft2 = normShift16(j); |
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d = logtab[ imultpow2(j,LOGTABBITS-15+nshft2) & |
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((1L<<LOGTABBITS)-1) ]; |
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d -= M_LN2*(gv*nshft + nshft2); |
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d = (double)TM_BRTSCALE*(d + log_inpsf); |
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bi = (int)(d + .5 - (d < 0.)); |
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} |
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/* world luminance */ |
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ls[i] = bi; |
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if (cs == TM_NOCHROM) /* no color? */ |
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continue; |
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/* mesopic adj. */ |
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if (tms->flags & TM_F_MESOPIC && bi < BMESUPPER) { |
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double slum = scotlum(cmon); |
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if (bi < BMESLOWER) |
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setcolor(cmon, slum, slum, slum); |
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else { |
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double pf; |
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pf = (1./256.)*tmMesofact[bi-BMESLOWER]; |
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if (tms->flags & TM_F_BW) |
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cmon[RED] = cmon[GRN] = cmon[BLU] = lum; |
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slum *= 1. - pf; |
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cmon[RED] = slum + pf*cmon[RED]; |
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cmon[GRN] = slum + pf*cmon[GRN]; |
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cmon[BLU] = slum + pf*cmon[BLU]; |
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} |
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} else if (tms->flags & TM_F_BW) { |
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cmon[RED] = cmon[GRN] = cmon[BLU] = lum; |
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} |
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bi = (double)MONGAMTSZ*tms->clf[RED]*cmon[RED]/lum; |
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cs[3*i ] = bi>=MONGAMTSZ ? 255 : mongamtab[bi]; |
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bi = (double)MONGAMTSZ*tms->clf[GRN]*cmon[GRN]/lum; |
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cs[3*i+1] = bi>=MONGAMTSZ ? 255 : mongamtab[bi]; |
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bi = (double)MONGAMTSZ*tms->clf[BLU]*cmon[BLU]/lum; |
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cs[3*i+2] = bi>=MONGAMTSZ ? 255 : mongamtab[bi]; |
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} |
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returnOK; |
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} |
