/* $XConsortium: LabGcLC.c,v 1.2 91/07/25 01:07:11 rws 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 * CIELabGcLC.c * * DESCRIPTION * Source for XcmsCIELabClipLab() gamut * compression function. */ #include "Xlibint.h" #include "Xcmsint.h" #include /* * INTERNALS * Internal defines that need NOT be exported to any package or * program using this package. */ #define MAXBISECTCOUNT 100 /* * EXTERNS */ extern Status _XcmsCIELabQueryMaxLCRGB(); /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * XcmsCIELabClipLab - Return the closest L* and chroma * * SYNOPSIS */ /* ARGSUSED */ Status XcmsCIELabClipLab (ccc, pColors_in_out, nColors, i, pCompressed) XcmsCCC ccc; XcmsColor *pColors_in_out; unsigned int nColors; unsigned int i; Bool *pCompressed; /* * DESCRIPTION * This routine will find the closest L* and chroma * for a specific hue. The color input is converted to * CIE L*u*v* format and returned as CIE XYZ format. * * Since this routine works with the L* within * pColor_in_out intermediate results may be returned * even though it may be invalid. * * RETURNS * XcmsFailure - Failure * XcmsSuccess - Succeeded * */ { Status retval; XcmsCCCRec myCCC; XcmsColor *pColor; XcmsColor Lab_max; XcmsFloat hue, chroma, maxChroma; XcmsFloat Chroma, bestChroma, Lstar, maxLstar, saveLstar; XcmsFloat bestLstar, bestastar, bestbstar; XcmsFloat nT, saveDist, tmpDist; XcmsRGBi rgb_max; int nCount, nMaxCount, nI, nILast; /* Use my own CCC */ memcpy ((char *)&myCCC, (char *)ccc, sizeof(XcmsCCCRec)); myCCC.clientWhitePt.format = XcmsUndefinedFormat;/* inherit screen white */ myCCC.gamutCompProc = (XcmsCompressionProc)NULL;/* no gamut compression func */ /* * Color specification passed as input can be assumed to: * 1. Be in XcmsCIEXYZFormat * 2. Already be white point adjusted for the Screen White Point. * This means that the white point now associated with this * color spec is the Screen White Point (even if the * ccc->clientWhitePt differs). */ pColor = pColors_in_out + i; if (ccc->visual->class < StaticColor) { /* * GRAY ! */ _XcmsDIConvertColors(ccc, pColor, ScreenWhitePointOfCCC(ccc), 1, XcmsCIELabFormat); _XcmsDIConvertColors(ccc, pColor, ScreenWhitePointOfCCC(ccc), 1, XcmsCIEXYZFormat); if (pCompressed) { *(pCompressed + i) = True; } return(XcmsSuccess); } /* Convert from CIEXYZ to CIELab format */ if (_XcmsDIConvertColors(&myCCC, pColor, ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIELabFormat) == XcmsFailure) { return(XcmsFailure); } /* Step 1: compute the maximum L* and chroma for this hue. */ /* This copy may be overkill but it preserves the pixel etc. */ saveLstar = pColor->spec.CIELab.L_star; hue = XCMS_CIELAB_PMETRIC_HUE(pColor->spec.CIELab.a_star, pColor->spec.CIELab.b_star); chroma = XCMS_CIELAB_PMETRIC_CHROMA(pColor->spec.CIELab.a_star, pColor->spec.CIELab.b_star); memcpy((char *)&Lab_max, (char *)pColor, sizeof(XcmsColor)); if (_XcmsCIELabQueryMaxLCRGB (&myCCC, hue, &Lab_max, &rgb_max) == XcmsFailure) { return (XcmsFailure); } maxLstar = Lab_max.spec.CIELab.L_star; /* Now check and return the appropriate L* */ if (saveLstar == maxLstar) { /* When the L* input is equal to the maximum L* */ /* merely return the maximum Lab point. */ memcpy((char *)pColor, (char *)&Lab_max, sizeof(XcmsColor)); retval = _XcmsDIConvertColors(&myCCC, pColor, ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIEXYZFormat); } else { /* return the closest point on the hue leaf. */ /* must do a bisection here to compute the delta e. */ maxChroma = XCMS_CIELAB_PMETRIC_CHROMA(Lab_max.spec.CIELab.a_star, Lab_max.spec.CIELab.b_star); nMaxCount = MAXBISECTCOUNT; nI = nMaxCount / 2; bestLstar = Lstar = pColor->spec.CIELab.L_star; bestastar = pColor->spec.CIELab.a_star; bestbstar = pColor->spec.CIELab.b_star; bestChroma = Chroma = chroma; saveDist = XCMS_SQRT(((Chroma - maxChroma) * (Chroma - maxChroma)) + ((Lstar - maxLstar) * (Lstar - maxLstar))); for (nCount = 0; nCount < nMaxCount; nCount++) { nT = (XcmsFloat) nI / (XcmsFloat) nMaxCount; if (saveLstar > maxLstar) { pColor->spec.RGBi.red = rgb_max.red * (1.0 - nT) + nT; pColor->spec.RGBi.green = rgb_max.green * (1.0 - nT) + nT; pColor->spec.RGBi.blue = rgb_max.blue * (1.0 - nT) + nT; } else { pColor->spec.RGBi.red = rgb_max.red - (rgb_max.red * nT); pColor->spec.RGBi.green = rgb_max.green - (rgb_max.green * nT); pColor->spec.RGBi.blue = rgb_max.blue - (rgb_max.blue * nT); } pColor->format = XcmsRGBiFormat; /* Convert from RGBi to CIE Lab */ if (_XcmsConvertColorsWithWhitePt(&myCCC, pColor, ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIELabFormat, (Bool *) NULL) == XcmsFailure) { return (XcmsFailure); } chroma = XCMS_CIELAB_PMETRIC_CHROMA(pColor->spec.CIELab.a_star, pColor->spec.CIELab.b_star); tmpDist = XCMS_SQRT(((Chroma - chroma) * (Chroma - chroma)) + ((Lstar - pColor->spec.CIELab.L_star) * (Lstar - pColor->spec.CIELab.L_star))); nILast = nI; if (tmpDist > saveDist) { nI /= 2; } else { nI = (nMaxCount + nI) / 2; saveDist = tmpDist; bestLstar = pColor->spec.CIELab.L_star; bestastar = pColor->spec.CIELab.a_star; bestbstar = pColor->spec.CIELab.b_star; bestChroma = chroma; } if (nI == nILast || nI == 0) { break; } } if (bestChroma >= maxChroma) { pColor->spec.CIELab.L_star = maxLstar; pColor->spec.CIELab.a_star = Lab_max.spec.CIELab.a_star; pColor->spec.CIELab.b_star = Lab_max.spec.CIELab.b_star; } else { pColor->spec.CIELab.L_star = bestLstar; pColor->spec.CIELab.a_star = bestastar; pColor->spec.CIELab.b_star = bestbstar; } retval = _XcmsDIConvertColors(&myCCC, pColor, ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIEXYZFormat); if (retval != XcmsFailure && pCompressed != NULL) { *(pCompressed + i) = True; } } return(retval); }