/* $Xorg: uvY.c,v 1.3 2000/08/17 19:45:23 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 * CIEuvy.c * * DESCRIPTION * This file contains routines that support the CIE u'v'Y * color space to include conversions to and from the CIE * XYZ space. * * DOCUMENTATION * "TekColor Color Management System, System Implementor's Manual" */ /* $XFree86: xc/lib/X11/uvY.c,v 1.3 2001/01/17 19:41:57 dawes Exp $ */ #include #include "Xlibint.h" #include "Xcmsint.h" #include "Cv.h" #include /* * FORWARD DECLARATIONS */ static int CIEuvY_ParseString(register char *spec, 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 CIEuvY to CIEXYZ */ static XcmsConversionProc Fl_CIEuvY_to_CIEXYZ[] = { XcmsCIEuvYToCIEXYZ, NULL }; /* * NULL terminated list of functions applied to get from CIEXYZ to CIEuvY */ static XcmsConversionProc Fl_CIEXYZ_to_CIEuvY[] = { XcmsCIEXYZToCIEuvY, NULL }; /* * GLOBALS */ /* * CIE uvY Color Space */ XcmsColorSpace XcmsCIEuvYColorSpace = { _XcmsCIEuvY_prefix, /* prefix */ XcmsCIEuvYFormat, /* id */ CIEuvY_ParseString, /* parseString */ Fl_CIEuvY_to_CIEXYZ, /* to_CIEXYZ */ Fl_CIEXYZ_to_CIEuvY, /* from_CIEXYZ */ 1 }; /************************************************************************ * * * PRIVATE ROUTINES * * * ************************************************************************/ /* * NAME * CIEuvY_ParseString * * SYNOPSIS */ static int CIEuvY_ParseString( register char *spec, XcmsColor *pColor) /* * DESCRIPTION * This routines takes a string and attempts to convert * it into a XcmsColor structure with XcmsCIEuvYFormat. * The assumed CIEuvY string syntax is: * CIEuvY:// * Where u, v, and Y 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, _XcmsCIEuvY_prefix, n) != 0) { return(XcmsFailure); } /* * Attempt to parse the value portion. */ if (sscanf(spec + n + 1, "%lf/%lf/%lf", &pColor->spec.CIEuvY.u_prime, &pColor->spec.CIEuvY.v_prime, &pColor->spec.CIEuvY.Y) != 3) { return(XcmsFailure); } pColor->format = XcmsCIEuvYFormat; pColor->pixel = 0; return(_XcmsCIEuvY_ValidSpec(pColor)); } /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * XcmsCIEuvY_ValidSpec * * SYNOPSIS */ Status _XcmsCIEuvY_ValidSpec( XcmsColor *pColor) /* * DESCRIPTION * Checks if color specification valid for CIE u'v'Y. * * RETURNS * XcmsFailure if invalid, * XcmsSuccess if valid. * */ { if (pColor->format != XcmsCIEuvYFormat || (pColor->spec.CIEuvY.Y < 0.0 - XMY_DBL_EPSILON) || (pColor->spec.CIEuvY.Y > 1.0 + XMY_DBL_EPSILON)) { return(XcmsFailure); } return(XcmsSuccess); } /* * NAME * XcmsCIEuvYToCIEXYZ - convert CIEuvY to CIEXYZ * * SYNOPSIS */ Status XcmsCIEuvYToCIEXYZ(XcmsCCC ccc, XcmsColor *puvY_WhitePt, XcmsColor *pColors_in_out, unsigned int nColors) /* * DESCRIPTION * Converts color specifications in an array of XcmsColor * structures from CIEuvY format to CIEXYZ format. * * RETURNS * XcmsFailure if failed, * XcmsSuccess if succeeded. * */ { XcmsCIEXYZ XYZ_return; XcmsColor whitePt; int i; XcmsColor *pColor = pColors_in_out; XcmsFloat div, x, y, z, Y; /* * Check arguments * Postpone checking puvY_WhitePt until it is actually needed * otherwise converting between XYZ and uvY will fail. */ if (pColors_in_out == NULL) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEXYZ form */ for (i = 0; i < nColors; i++, pColor++) { /* Make sure original format is CIEuvY */ if (!_XcmsCIEuvY_ValidSpec(pColor)) { return(XcmsFailure); } /* * Convert to CIEXYZ */ Y = pColor->spec.CIEuvY.Y; /* Convert color u'v' to xyz space */ div = (6.0 * pColor->spec.CIEuvY.u_prime) - (16.0 * pColor->spec.CIEuvY.v_prime) + 12.0; if (div == 0.0) { /* use white point since div == 0 */ if (puvY_WhitePt == NULL ) { return(XcmsFailure); } /* * Make sure white point is in CIEuvY form */ if (puvY_WhitePt->format != XcmsCIEuvYFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)puvY_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { return(XcmsFailure); } puvY_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (puvY_WhitePt->spec.CIEuvY.Y != 1.0) { return(XcmsFailure); } div = (6.0 * puvY_WhitePt->spec.CIEuvY.u_prime) - (16.0 * puvY_WhitePt->spec.CIEuvY.v_prime) + 12.0; if (div == 0) { /* internal error */ return(XcmsFailure); } x = 9.0 * puvY_WhitePt->spec.CIEuvY.u_prime / div; y = 4.0 * puvY_WhitePt->spec.CIEuvY.v_prime / div; } else { x = 9.0 * pColor->spec.CIEuvY.u_prime / div; y = 4.0 * pColor->spec.CIEuvY.v_prime / div; } z = 1.0 - x - y; /* Convert from xyz to XYZ */ /* Conversion uses color normalized lightness based on Y */ if (y != 0.0) { XYZ_return.X = x * Y / y; } else { XYZ_return.X = x; } XYZ_return.Y = Y; if (y != 0.0) { XYZ_return.Z = z * Y / y; } else { XYZ_return.Z = z; } memcpy((char *)&pColor->spec.CIEXYZ, (char *)&XYZ_return, sizeof(XcmsCIEXYZ)); /* Identify that format is now CIEXYZ */ pColor->format = XcmsCIEXYZFormat; } return(XcmsSuccess); } /* * NAME * XcmsCIEXYZToCIEuvY - convert CIEXYZ to CIEuvY * * SYNOPSIS */ Status XcmsCIEXYZToCIEuvY(XcmsCCC ccc, XcmsColor *puvY_WhitePt, XcmsColor *pColors_in_out, unsigned int nColors) /* * DESCRIPTION * Converts color specifications in an array of XcmsColor * structures from CIEXYZ format to CIEuvY format. * * RETURNS * XcmsFailure if failed, * XcmsSuccess if succeeded. * */ { XcmsCIEuvY uvY_return; XcmsColor whitePt; int i; XcmsColor *pColor = pColors_in_out; XcmsFloat div; /* * Check arguments * Postpone checking puvY_WhitePt until it is actually needed * otherwise converting between XYZ and uvY will fail. */ if (pColors_in_out == NULL) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEuvY form */ for (i = 0; i < nColors; i++, pColor++) { /* Make sure original format is CIEXYZ */ if (!_XcmsCIEXYZ_ValidSpec(pColor)) { return(XcmsFailure); } /* Convert to CIEuvY */ div = pColor->spec.CIEXYZ.X + (15.0 * pColor->spec.CIEXYZ.Y) + (3.0 * pColor->spec.CIEXYZ.Z); if (div == 0.0) { /* Use white point since div == 0.0 */ if (puvY_WhitePt == NULL ) { return(XcmsFailure); } /* * Make sure white point is in CIEuvY form */ if (puvY_WhitePt->format != XcmsCIEuvYFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)puvY_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { return(XcmsFailure); } puvY_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (puvY_WhitePt->spec.CIEuvY.Y != 1.0) { return(XcmsFailure); } uvY_return.Y = pColor->spec.CIEXYZ.Y; uvY_return.u_prime = puvY_WhitePt->spec.CIEuvY.u_prime; uvY_return.v_prime = puvY_WhitePt->spec.CIEuvY.v_prime; } else { uvY_return.u_prime = 4.0 * pColor->spec.CIEXYZ.X / div; uvY_return.v_prime = 9.0 * pColor->spec.CIEXYZ.Y / div; uvY_return.Y = pColor->spec.CIEXYZ.Y; } memcpy((char *)&pColor->spec.CIEuvY, (char *)&uvY_return, sizeof(XcmsCIEuvY)); /* Identify that format is now CIEuvY */ pColor->format = XcmsCIEuvYFormat; } return(XcmsSuccess); }