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#include <string.h> |
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#include "pcond.h" |
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#include "random.h" |
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#define CVRATIO 0.025 /* fraction of samples allowed > env. */ |
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double mhistot; /* modified histogram total */ |
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double cumf[HISTRES+1]; /* cumulative distribution function */ |
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static double centprob(int x, int y); |
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static double centprob(int x, int y); |
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static void mkcumf(void); |
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static double cf(double b); |
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static double BLw(double Lw); |
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static double cf(double b); |
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static double BLw(double Lw); |
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static float *getlumsamp(int n); |
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#if ADJ_VEIL |
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static void mkcrfimage(void); |
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#endif |
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} |
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static float * |
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getlumsamp(int n) /* get set of random point sample luminances */ |
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{ |
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float *ls = (float *)malloc(n*sizeof(float)); |
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COLR *cscan = (COLR *)malloc(scanlen(&inpres)*sizeof(COLR)); |
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long startpos = ftell(infp); |
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long npleft = (long)inpres.xr*inpres.yr; |
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int x; |
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if ((ls == NULL) | (cscan == NULL)) |
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syserror("malloc"); |
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x = 0; /* read/convert samples */ |
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while (n > 0) { |
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COLOR col; |
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int sv = 0; |
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double rval, cumprob = 0; |
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if (x <= 0 && fread2colrs(cscan, x=scanlen(&inpres), infp, |
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NCSAMP, WLPART) < 0) { |
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fprintf(stderr, "%s: %s: scanline read error\n", |
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progname, infn); |
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exit(1); |
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} |
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rval = frandom(); /* random distance to next sample */ |
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while ((cumprob += (1.-cumprob)*n/(npleft-sv)) < rval) |
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sv++; |
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if (x < ++sv) { /* out of pixels in this scanline */ |
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npleft -= x; |
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x = 0; |
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continue; |
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} |
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x -= sv; |
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colr_color(col, cscan[x]); |
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ls[--n] = plum(col); |
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npleft -= sv; |
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} |
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free(cscan); /* clean up and reset file pointer */ |
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if (fseek(infp, startpos, SEEK_SET) < 0) |
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syserror("fseek"); |
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return(ls); |
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} |
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void |
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comphist(void) /* create foveal sampling histogram */ |
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{ |
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double l, b, w, lwmin, lwmax; |
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float *lumsamp; |
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int nlumsamp; |
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int x, y; |
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/* check for precalculated histogram */ |
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if (what2do&DO_PREHIST) |
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for (y = 0; y < fvyr; y++) |
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for (x = 0; x < fvxr; x++) { |
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l = plum(fovscan(y)[x]); |
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if ((l < lwmin) & (l > LMIN)) lwmin = l; |
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if ((l > lwmax) & (l < LMAX)) lwmax = l; |
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if (l < lwmin) lwmin = l; |
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if (l > lwmax) lwmax = l; |
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} |
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/* sample luminance pixels */ |
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nlumsamp = fvxr*fvyr*16; |
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if (nlumsamp > inpres.xr*inpres.yr) |
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nlumsamp = inpres.xr*inpres.yr; |
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lumsamp = getlumsamp(nlumsamp); |
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for (x = nlumsamp; x--; ) { |
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l = lumsamp[x]; |
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if (l < lwmin) lwmin = l; |
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if (l > lwmax) lwmax = l; |
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} |
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lwmax *= 1.01; |
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if (lwmax > LMAX) |
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lwmax = LMAX; |
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/* (re)compute histogram */ |
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bwavg = 0.; |
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histot = 0.; |
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for (x = 0; x < HISTRES; x++) |
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bwhist[x] = 0.; |
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memset(bwhist, 0, sizeof(bwhist)); |
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/* global average */ |
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if (!(what2do&DO_FIXHIST) || fixfrac < 1.-FTINY) |
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if (!(what2do&DO_FIXHIST) || fixfrac < 1.-FTINY) { |
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for (y = 0; y < fvyr; y++) |
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for (x = 0; x < fvxr; x++) { |
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l = plum(fovscan(y)[x]); |
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bwhist[bwhi(b)] += w; |
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histot += w; |
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} |
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/* weight for point luminances */ |
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w = 1. * histot / nlumsamp; |
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for (x = nlumsamp; x--; ) { |
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l = lumsamp[x]; |
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if (l < lwmin+FTINY) continue; |
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if (l >= lwmax-FTINY) continue; |
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b = Bl(l); |
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bwavg += w*b; |
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bwhist[bwhi(b)] += w; |
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histot += w; |
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} |
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} |
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/* average fixation points */ |
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if (what2do&DO_FIXHIST && nfixations > 0) { |
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if (histot > FTINY) |
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bwhist[1] *= 0.5; |
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bwhist[0] += bwhist[1]; |
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} |
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free(lumsamp); |
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} |
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modhist[i] = ceiling; |
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} |
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} |
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< |
} while (trimmings > histot*CVRATIO); |
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> |
} while (trimmings > mhistot*CVRATIO); |
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#if ADJ_VEIL |
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mkcrfimage(); /* contrast reduction image */ |
