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#include "color.h" |
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#ifdef SPEC_RGB |
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/* |
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* The following table contains the CIE tristimulus integrals |
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* for X, Y, and Z. The table is cumulative, so that |
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* each color coordinate integrates to 1. |
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*/ |
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|
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#define STARTWL 380 /* starting wavelength (nanometers) */ |
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#define INCWL 10 /* wavelength increment */ |
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#define NINC 40 /* # of values */ |
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|
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static BYTE chroma[3][NINC] = { |
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{ /* X */ |
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0, 0, 0, 2, 6, 13, 22, 30, 36, 41, |
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42, 43, 43, 44, 46, 52, 60, 71, 87, 106, |
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128, 153, 178, 200, 219, 233, 243, 249, 252, 254, |
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
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}, { /* Y */ |
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0, 0, 0, 0, 0, 1, 2, 4, 7, 11, |
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17, 24, 34, 48, 64, 84, 105, 127, 148, 169, |
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188, 205, 220, 232, 240, 246, 250, 253, 254, 255, |
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
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}, { /* Z */ |
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0, 0, 2, 10, 32, 66, 118, 153, 191, 220, |
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237, 246, 251, 253, 254, 255, 255, 255, 255, 255, |
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, |
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
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} |
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}; |
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|
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|
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spec_rgb(col, s, e) /* comput RGB color from spectral range */ |
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COLOR col; |
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int s, e; |
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{ |
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COLOR ciecolor; |
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|
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spec_cie(ciecolor, s, e); |
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cie_rgb(col, ciecolor); |
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} |
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|
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|
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spec_cie(col, s, e) /* compute a color from a spectral range */ |
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COLOR col; /* returned color */ |
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int s, e; /* starting and ending wavelengths */ |
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{ |
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register int i, d, r; |
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|
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s -= STARTWL; |
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if (s < 0) |
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s = 0; |
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|
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e -= STARTWL; |
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if (e >= INCWL*(NINC - 1)) |
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e = INCWL*(NINC - 1) - 1; |
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|
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d = e / INCWL; /* interpolate values */ |
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r = e % INCWL; |
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for (i = 0; i < 3; i++) |
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col[i] = chroma[i][d]*(INCWL - r) + chroma[i][d + 1]*r; |
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|
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d = s / INCWL; |
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r = s % INCWL; |
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for (i = 0; i < 3; i++) |
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col[i] -= chroma[i][d]*(INCWL - r) - chroma[i][d + 1]*r; |
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|
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col[RED] = (col[RED] + 0.5) / (256*INCWL); |
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col[GRN] = (col[GRN] + 0.5) / (256*INCWL); |
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col[BLU] = (col[BLU] + 0.5) / (256*INCWL); |
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} |
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|
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|
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cie_rgb(rgbcolor, ciecolor) /* convert CIE to RGB (NTSC) */ |
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register COLOR rgbcolor, ciecolor; |
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{ |
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static float cmat[3][3] = { |
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1.73, -.48, -.26, |
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-.81, 1.65, -.02, |
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.08, -.17, 1.28, |
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}; |
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register int i; |
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|
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for (i = 0; i < 3; i++) { |
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rgbcolor[i] = cmat[i][0]*ciecolor[0] + |
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cmat[i][1]*ciecolor[1] + |
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cmat[i][2]*ciecolor[2] ; |
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if (rgbcolor[i] < 0.0) |
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rgbcolor[i] = 0.0; |
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} |
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} |
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#endif |
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|
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|
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fputresolu(ord, xres, yres, fp) /* put x and y resolution */ |
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register int ord; |
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int xres, yres; |
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FILE *fp; |
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{ |
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if (ord&YMAJOR) |
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fprintf(fp, "%cY %d %cX %d\n", |
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ord&YDECR ? '-' : '+', yres, |
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ord&XDECR ? '-' : '+', xres); |
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else |
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fprintf(fp, "%cX %d %cY %d\n", |
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ord&XDECR ? '-' : '+', xres, |
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ord&YDECR ? '-' : '+', yres); |
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} |
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|
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|
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fgetresolu(xrp, yrp, fp) /* get x and y resolution */ |
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int *xrp, *yrp; |
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FILE *fp; |
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{ |
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char buf[64], *xndx, *yndx; |
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register char *cp; |
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register int ord; |
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|
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if (fgets(buf, sizeof(buf), fp) == NULL) |
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return(-1); |
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xndx = yndx = NULL; |
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for (cp = buf+1; *cp; cp++) |
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if (*cp == 'X') |
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xndx = cp; |
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else if (*cp == 'Y') |
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yndx = cp; |
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if (xndx == NULL || yndx == NULL) |
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return(-1); |
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ord = 0; |
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if (xndx > yndx) ord |= YMAJOR; |
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if (xndx[-1] == '-') ord |= XDECR; |
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if (yndx[-1] == '-') ord |= YDECR; |
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if ((*xrp = atoi(xndx+1)) <= 0) |
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return(-1); |
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if ((*yrp = atoi(yndx+1)) <= 0) |
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return(-1); |
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return(ord); |
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} |
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|
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|
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fwritecolrs(scanline, len, fp) /* write out a colr scanline */ |
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register COLR *scanline; |
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int len; |
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col[GRN] = (clr[GRN] + 0.5)*f; |
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col[BLU] = (clr[BLU] + 0.5)*f; |
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} |
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} |
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|
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|
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int |
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colr_norm(clr, nclr) /* normalize a short color, return shift */ |
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COLR clr, nclr; |
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{ |
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register int c; |
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register int shift = clr[EXP]-COLXS; |
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|
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if (shift > 0) { |
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if (shift >= 8) { |
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nclr[RED] = nclr[GRN] = nclr[BLU] = 255; |
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} else { |
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c = clr[RED] << shift; |
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nclr[RED] = c > 255 ? 255 : c; |
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c = clr[GRN] << shift; |
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nclr[GRN] = c > 255 ? 255 : c; |
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c = clr[BLU] << shift; |
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nclr[BLU] = c > 255 ? 255 : c; |
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} |
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} else if (shift < 0) { |
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if (shift <= -8) { |
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nclr[RED] = nclr[GRN] = nclr[BLU] = 0; |
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} else { |
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nclr[RED] = clr[RED] >> -shift; |
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nclr[GRN] = clr[GRN] >> -shift; |
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nclr[BLU] = clr[BLU] >> -shift; |
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} |
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} else { |
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nclr[RED] = clr[RED]; |
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nclr[GRN] = clr[GRN]; |
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nclr[BLU] = clr[BLU]; |
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} |
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nclr[EXP] = COLXS; |
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return(shift); |
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} |
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