/* $Xorg: LabMxC.c,v 1.3 2000/08/17 19:44:40 cpqbld Exp $ */ /* * Code and supporting documentation (c) Copyright 1990 1991 Tektronix, Inc. * All Rights Reserved * * This file is a component of an X Window System-specific implementation * of XCMS based on the TekColor Color Management System. Permission is * hereby granted to use, copy, modify, sell, and otherwise distribute this * software and its documentation for any purpose and without fee, provided * that this copyright, permission, and disclaimer notice is reproduced in * all copies of this software and in supporting documentation. TekColor * is a trademark of Tektronix, Inc. * * Tektronix makes no representation about the suitability of this software * for any purpose. It is provided "as is" and with all faults. * * TEKTRONIX DISCLAIMS ALL WARRANTIES APPLICABLE TO THIS SOFTWARE, * INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A * PARTICULAR PURPOSE. IN NO EVENT SHALL TEKTRONIX BE LIABLE FOR ANY * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER * RESULTING FROM LOSS OF USE, DATA, OR PROFITS, WHETHER IN AN ACTION OF * CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN * CONNECTION WITH THE USE OR THE PERFORMANCE OF THIS SOFTWARE. * * * * NAME * CIELabMxC.c * * DESCRIPTION * Source for the XcmsCIELabQueryMaxC() gamut boundary * querying routine. * */ /* $XFree86: xc/lib/X11/LabMxC.c,v 1.3 2001/01/17 19:41:39 dawes Exp $ */ #include "Xlibint.h" #include "Xcmsint.h" #include /* * DEFINES */ #define MAXBISECTCOUNT 100 #define EPS (XcmsFloat)0.001 #define START_CHROMA (XcmsFloat)3.6 #define TOPL (XcmsFloat)100.0 /* * EXTERNS */ extern Status _XcmsCIELabQueryMaxLCRGB(); /* CvColW.c */ extern Status _XcmsConvertColorsWithWhitePt(); /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * XcmsCIELabQueryMaxC - max chroma for a hue_angle and L_star * * SYNOPSIS */ Status XcmsCIELabQueryMaxC(ccc, hue_angle, L_star, pColor_return) XcmsCCC ccc; XcmsFloat hue_angle; /* hue angle in degrees */ XcmsFloat L_star; XcmsColor *pColor_return; /* * DESCRIPTION * Return the maximum chroma for a specific hue_angle and L_star. * The returned format is in XcmsCIELabFormat. * * * ASSUMPTIONS * This routine assumes that the white point associated with * the color specification is the Screen White Point. The * Screen White Point will also be associated with the * returned color specification. * * RETURNS * XcmsFailure - Failure * XcmsSuccess - Succeeded * */ { XcmsCCCRec myCCC; XcmsColor tmp; XcmsColor max_lc; XcmsFloat n_L_star, last_L_star, prev_L_star; XcmsFloat hue, lastaStar, lastbStar, /*lastChroma,*/ maxDist, nT, rFactor; XcmsRGBi rgb_saved; int nCount, nMaxCount; /* * Check Arguments */ if (ccc == NULL || pColor_return == NULL) { return(XcmsFailure); } /* Use my own CCC and inherit screen white Pt */ memcpy ((char *)&myCCC, (char *)ccc, sizeof(XcmsCCCRec)); myCCC.clientWhitePt.format = XcmsUndefinedFormat; myCCC.gamutCompProc = (XcmsCompressionProc)NULL;/* no gamut comp func */ while (hue_angle < 0.0) { hue_angle += 360.0; } while (hue_angle >= 360.0) { hue_angle -= 360.0; } hue = radians(hue_angle); tmp.spec.CIELab.L_star = L_star; tmp.spec.CIELab.a_star = XCMS_CIEASTAROFHUE(hue, START_CHROMA); tmp.spec.CIELab.b_star = XCMS_CIEBSTAROFHUE(hue, START_CHROMA); tmp.pixel = pColor_return->pixel; tmp.format = XcmsCIELabFormat; /* Step 1: compute the maximum L_star and chroma for this hue. */ memcpy((char *)&max_lc, (char *)&tmp, sizeof(XcmsColor)); if (_XcmsCIELabQueryMaxLCRGB(&myCCC, hue, &max_lc, &rgb_saved) == XcmsFailure) { return(XcmsFailure); } /* * Step 2: Do a bisection here to compute the maximum chroma * Note the differences between when the point to be found * is above the maximum LC point and when it is below. */ if (L_star <= max_lc.spec.CIELab.L_star) { maxDist = max_lc.spec.CIELab.L_star; } else { maxDist = TOPL - max_lc.spec.CIELab.L_star; } n_L_star = L_star; last_L_star = -1.0; nMaxCount = MAXBISECTCOUNT; rFactor = 1.0; for (nCount = 0; nCount < nMaxCount; nCount++) { prev_L_star = last_L_star; last_L_star = tmp.spec.CIELab.L_star; /* lastChroma = XCMS_CIELAB_PMETRIC_CHROMA(tmp.spec.CIELab.a_star, */ /* tmp.spec.CIELab.b_star); */ lastaStar = tmp.spec.CIELab.a_star; lastbStar = tmp.spec.CIELab.b_star; nT = (n_L_star - max_lc.spec.CIELab.L_star) / maxDist * rFactor; if (nT > 0) { tmp.spec.RGBi.red = rgb_saved.red * (1.0 - nT) + nT; tmp.spec.RGBi.green = rgb_saved.green * (1.0 - nT) + nT; tmp.spec.RGBi.blue = rgb_saved.blue * (1.0 - nT) + nT; } else { tmp.spec.RGBi.red = rgb_saved.red + (rgb_saved.red * nT); tmp.spec.RGBi.green = rgb_saved.green + (rgb_saved.green * nT); tmp.spec.RGBi.blue = rgb_saved.blue + (rgb_saved.blue * nT); } tmp.format = XcmsRGBiFormat; /* convert from RGB to CIELab */ if (_XcmsConvertColorsWithWhitePt(&myCCC, &tmp, ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIELabFormat, (Bool *) NULL) == XcmsFailure) { return(XcmsFailure); } /* * Now check if we've reached the target L_star */ /* printf("result Lstar = %lf\n", tmp.spec.CIELab.L_star); */ if (tmp.spec.CIELab.L_star <= L_star + EPS && tmp.spec.CIELab.L_star >= L_star - EPS) { memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor)); return(XcmsSuccess); } if (nT > 0) { n_L_star += ((TOPL - n_L_star) * (L_star - tmp.spec.CIELab.L_star)) / (TOPL - L_star); } else { n_L_star *= L_star / tmp.spec.CIELuv.L_star; } if (tmp.spec.CIELab.L_star <= prev_L_star + EPS && tmp.spec.CIELab.L_star >= prev_L_star - EPS) { rFactor *= 0.5; /* selective relaxation employed */ /* printf("rFactor = %lf\n", rFactor); */ } } if (XCMS_FABS(last_L_star - L_star) < XCMS_FABS(tmp.spec.CIELab.L_star - L_star)) { tmp.spec.CIELab.a_star = lastaStar; tmp.spec.CIELab.b_star = lastbStar; /* tmp.spec.CIELab.a_star = XCMS_CIEASTAROFHUE(hue, lastChroma); */ /* tmp.spec.CIELab.b_star = XCMS_CIEBSTAROFHUE(hue, lastChroma); */ } tmp.spec.CIELab.L_star = L_star; memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor)); return(XcmsSuccess); }