/* $Xorg: Luv.c,v 1.3 2000/08/17 19:44:41 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 * CIELuv.c * * DESCRIPTION * This file contains routines that support the CIE L*u*v* * color space to include conversions to and from the CIE * XYZ space. * * DOCUMENTATION * "TekColor Color Management System, System Implementor's Manual" * and * Fred W. Billmeyer & Max Saltzman, "Principles of Color * Technology", John Wily & Sons, Inc, 1981. */ /* $XFree86: xc/lib/X11/Luv.c,v 1.3 2001/01/17 19:41:39 dawes Exp $ */ #include #include "Xlibint.h" #include "Xcmsint.h" #include "Cv.h" #include /* sscanf */ /* * FORWARD DECLARATIONS */ static int CIELuv_ParseString(register char *spec, XcmsColor *pColor); static Status XcmsCIELuv_ValidSpec(XcmsColor *pColor); /* * DEFINES * Internal definitions that need NOT be exported to any package * or program using this package. */ #ifdef DBL_EPSILON # define XMY_DBL_EPSILON DBL_EPSILON #else # define XMY_DBL_EPSILON 0.00001 #endif /* * LOCAL VARIABLES */ /* * NULL terminated list of functions applied to get from CIELuv to CIEXYZ */ static XcmsConversionProc Fl_CIELuv_to_CIEXYZ[] = { XcmsCIELuvToCIEuvY, XcmsCIEuvYToCIEXYZ, NULL }; /* * NULL terminated list of functions applied to get from CIEXYZ to CIELuv */ static XcmsConversionProc Fl_CIEXYZ_to_CIELuv[] = { XcmsCIEXYZToCIEuvY, XcmsCIEuvYToCIELuv, NULL }; /* * GLOBALS */ /* * CIE Luv Color Space */ XcmsColorSpace XcmsCIELuvColorSpace = { _XcmsCIELuv_prefix, /* prefix */ XcmsCIELuvFormat, /* id */ CIELuv_ParseString, /* parseString */ Fl_CIELuv_to_CIEXYZ, /* to_CIEXYZ */ Fl_CIEXYZ_to_CIELuv, /* from_CIEXYZ */ 1 }; /************************************************************************ * * * PRIVATE ROUTINES * * * ************************************************************************/ /* * NAME * CIELuv_ParseString * * SYNOPSIS */ static int CIELuv_ParseString( register char *spec, XcmsColor *pColor) /* * DESCRIPTION * This routines takes a string and attempts to convert * it into a XcmsColor structure with XcmsCIELuvFormat. * The assumed CIELuv string syntax is: * CIELuv:// * Where L, u, and v are in string input format for floats * consisting of: * a. an optional sign * b. a string of numbers possibly containing a decimal point, * c. an optional exponent field containing an 'E' or 'e' * followed by a possibly signed integer string. * * RETURNS * 0 if failed, non-zero otherwise. */ { int n; char *pchar; if ((pchar = strchr(spec, ':')) == NULL) { return(XcmsFailure); } n = (int)(pchar - spec); /* * Check for proper prefix. */ if (strncmp(spec, _XcmsCIELuv_prefix, n) != 0) { return(XcmsFailure); } /* * Attempt to parse the value portion. */ if (sscanf(spec + n + 1, "%lf/%lf/%lf", &pColor->spec.CIELuv.L_star, &pColor->spec.CIELuv.u_star, &pColor->spec.CIELuv.v_star) != 3) { return(XcmsFailure); } pColor->format = XcmsCIELuvFormat; pColor->pixel = 0; return(XcmsCIELuv_ValidSpec(pColor)); } /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * XcmsCIELuv_ValidSpec * * SYNOPSIS */ static Status XcmsCIELuv_ValidSpec( XcmsColor *pColor) /* * DESCRIPTION * Checks if color specification valid for CIE L*u*v*. * * RETURNS * XcmsFailure if invalid, * XcmsSuccess if valid. * */ { if (pColor->format != XcmsCIELuvFormat || (pColor->spec.CIELuv.L_star < 0.0 - XMY_DBL_EPSILON) || (pColor->spec.CIELuv.L_star > 100.0 + XMY_DBL_EPSILON)) { return(XcmsFailure); } return(XcmsSuccess); } /* * NAME * XcmsCIELuvToCIEuvY - convert CIELuv to CIEuvY * * SYNOPSIS */ Status XcmsCIELuvToCIEuvY(XcmsCCC ccc, XcmsColor *pLuv_WhitePt, XcmsColor *pColors_in_out, unsigned int nColors) /* * DESCRIPTION * Converts color specifications in an array of XcmsColor * structures from CIELuv format to CIEuvY format. * * RETURNS * XcmsFailure if failed, * XcmsSuccess if succeeded. * */ { XcmsColor *pColor = pColors_in_out; XcmsColor whitePt; XcmsCIEuvY uvY_return; XcmsFloat tmpVal; register int i; /* * Check arguments */ if (pLuv_WhitePt == NULL || pColors_in_out == NULL) { return(XcmsFailure); } /* * Make sure white point is in CIEuvY form */ if (pLuv_WhitePt->format != XcmsCIEuvYFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { return(XcmsFailure); } pLuv_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (pLuv_WhitePt->spec.CIEuvY.Y != 1.0) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEXYZ form */ for (i = 0; i < nColors; i++, pColor++) { /* Make sure original format is CIELuv and is valid */ if (!XcmsCIELuv_ValidSpec(pColor)) { return(XcmsFailure); } if (pColor->spec.CIELuv.L_star < 7.99953624) { uvY_return.Y = pColor->spec.CIELuv.L_star / 903.29; } else { tmpVal = (pColor->spec.CIELuv.L_star + 16.0) / 116.0; uvY_return.Y = tmpVal * tmpVal * tmpVal; /* tmpVal ** 3 */ } if (pColor->spec.CIELuv.L_star == 0.0) { uvY_return.u_prime = pLuv_WhitePt->spec.CIEuvY.u_prime; uvY_return.v_prime = pLuv_WhitePt->spec.CIEuvY.v_prime; } else { tmpVal = 13.0 * (pColor->spec.CIELuv.L_star / 100.0); uvY_return.u_prime = pColor->spec.CIELuv.u_star/tmpVal + pLuv_WhitePt->spec.CIEuvY.u_prime; uvY_return.v_prime = pColor->spec.CIELuv.v_star/tmpVal + pLuv_WhitePt->spec.CIEuvY.v_prime; } /* Copy result to pColor */ memcpy((char *)&pColor->spec, (char *)&uvY_return, sizeof(XcmsCIEuvY)); /* Identify that the format is now CIEuvY */ pColor->format = XcmsCIEuvYFormat; } return(XcmsSuccess); } /* * NAME * XcmsCIEuvYToCIELuv - convert CIEuvY to CIELuv * * SYNOPSIS */ Status XcmsCIEuvYToCIELuv(XcmsCCC ccc, XcmsColor *pLuv_WhitePt, XcmsColor *pColors_in_out, unsigned int nColors) /* * DESCRIPTION * Converts color specifications in an array of XcmsColor * structures from CIEuvY format to CIELab format. * * RETURNS * XcmsFailure if failed, * XcmsSuccess if succeeded. * */ { XcmsColor *pColor = pColors_in_out; XcmsColor whitePt; XcmsCIELuv Luv_return; XcmsFloat tmpVal; register int i; /* * Check arguments */ if (pLuv_WhitePt == NULL || pColors_in_out == NULL) { return(XcmsFailure); } /* * Make sure white point is in CIEuvY form */ if (pLuv_WhitePt->format != XcmsCIEuvYFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { return(XcmsFailure); } pLuv_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (pLuv_WhitePt->spec.CIEuvY.Y != 1.0) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEXYZ form */ for (i = 0; i < nColors; i++, pColor++) { if (!_XcmsCIEuvY_ValidSpec(pColor)) { return(XcmsFailure); } /* Now convert the uvY to Luv */ Luv_return.L_star = (pColor->spec.CIEuvY.Y < 0.008856) ? (pColor->spec.CIEuvY.Y * 903.29) : ((XcmsFloat)(XCMS_CUBEROOT(pColor->spec.CIEuvY.Y) * 116.0) - 16.0); tmpVal = 13.0 * (Luv_return.L_star / 100.0); Luv_return.u_star = tmpVal * (pColor->spec.CIEuvY.u_prime - pLuv_WhitePt->spec.CIEuvY.u_prime); Luv_return.v_star = tmpVal * (pColor->spec.CIEuvY.v_prime - pLuv_WhitePt->spec.CIEuvY.v_prime); /* Copy result to pColor */ memcpy((char *)&pColor->spec, (char *)&Luv_return, sizeof(XcmsCIELuv)); /* Identify that the format is now CIEuvY */ pColor->format = XcmsCIELuvFormat; } return(XcmsSuccess); }