/* $Xorg: xyY.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 * CIExyY.c * * DESCRIPTION * This file contains routines that support the CIE xyY * 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/xyY.c,v 1.3 2001/01/17 19:41:57 dawes Exp $ */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include <stdio.h> #include <X11/Xos.h> #include "Xlibint.h" #include "Xcmsint.h" #include "Cv.h" /* * DEFINES */ #define EPS 0.00001 /* some extremely small number */ #ifdef DBL_EPSILON # define XMY_DBL_EPSILON DBL_EPSILON #else # define XMY_DBL_EPSILON 0.00001 #endif /* * FORWARD DECLARATIONS */ static int CIExyY_ParseString(register char *spec, XcmsColor *pColor); static Status XcmsCIExyY_ValidSpec(XcmsColor *pColor); /* * LOCAL VARIABLES */ /* * NULL terminated list of functions applied to get from CIExyY to CIEXYZ */ static XcmsConversionProc Fl_CIExyY_to_CIEXYZ[] = { XcmsCIExyYToCIEXYZ, NULL }; /* * NULL terminated list of functions applied to get from CIEXYZ to CIExyY */ static XcmsConversionProc Fl_CIEXYZ_to_CIExyY[] = { XcmsCIEXYZToCIExyY, NULL }; /* * GLOBALS */ /* * CIE xyY Color Space */ XcmsColorSpace XcmsCIExyYColorSpace = { _XcmsCIExyY_prefix, /* prefix */ XcmsCIExyYFormat, /* id */ CIExyY_ParseString, /* parseString */ Fl_CIExyY_to_CIEXYZ, /* to_CIEXYZ */ Fl_CIEXYZ_to_CIExyY, /* from_CIEXYZ */ 1 }; /************************************************************************ * * * PRIVATE ROUTINES * * * ************************************************************************/ /* * NAME * CIExyY_ParseString * * SYNOPSIS */ static int CIExyY_ParseString( register char *spec, XcmsColor *pColor) /* * DESCRIPTION * This routines takes a string and attempts to convert * it into a XcmsColor structure with XcmsCIExyYFormat. * The assumed CIExyY string syntax is: * CIExyY:<x>/<y>/<Y> * Where x, y, 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, _XcmsCIExyY_prefix, n) != 0) { return(XcmsFailure); } /* * Attempt to parse the value portion. */ if (sscanf(spec + n + 1, "%lf/%lf/%lf", &pColor->spec.CIExyY.x, &pColor->spec.CIExyY.y, &pColor->spec.CIExyY.Y) != 3) { return(XcmsFailure); } pColor->format = XcmsCIExyYFormat; pColor->pixel = 0; return(XcmsCIExyY_ValidSpec(pColor)); } /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * CIExyY_ValidSpec() * * SYNOPSIS */ static Status XcmsCIExyY_ValidSpec( XcmsColor *pColor) /* * DESCRIPTION * Checks a valid CIExyY color specification. * * RETURNS * XcmsFailure if invalid. * XcmsSuccess if valid. * */ { if (pColor->format != XcmsCIExyYFormat || (pColor->spec.CIExyY.x < 0.0 - XMY_DBL_EPSILON) || (pColor->spec.CIExyY.x > 1.0 + XMY_DBL_EPSILON) || (pColor->spec.CIExyY.y < 0.0 - XMY_DBL_EPSILON) || (pColor->spec.CIExyY.y > 1.0 + XMY_DBL_EPSILON) || (pColor->spec.CIExyY.Y < 0.0 - XMY_DBL_EPSILON) || (pColor->spec.CIExyY.Y > 1.0 + XMY_DBL_EPSILON)) { return(XcmsFailure); } return(XcmsSuccess); } /* * NAME * XcmsCIExyYToCIEXYZ - convert CIExyY to CIEXYZ * * SYNOPSIS */ Status XcmsCIExyYToCIEXYZ(ccc, pxyY_WhitePt, pColors_in_out, nColors) XcmsCCC ccc; XcmsColor *pxyY_WhitePt; XcmsColor *pColors_in_out; unsigned int nColors; /* * DESCRIPTION * Converts color specifications in an array of XcmsColor * structures from CIExyY format to CIEXYZ format. * * RETURNS * XcmsFailure if failed, * XcmsSuccess if succeeded. */ { XcmsColor *pColor = pColors_in_out; XcmsColor whitePt; XcmsCIEXYZ XYZ_return; XcmsFloat div; /* temporary storage in case divisor is zero */ XcmsFloat u, v, x, y, z; /* temporary storage */ register int i; /* * Check arguments */ if (pxyY_WhitePt == NULL || 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 CIExyY and valid */ if (!XcmsCIExyY_ValidSpec(pColor)) { return(XcmsFailure); } if ((div = (-2 * pColor->spec.CIExyY.x) + (12 * pColor->spec.CIExyY.y) + 3) == 0.0) { /* Note that the divisor is zero */ /* This return is abitrary. */ XYZ_return.X = 0; XYZ_return.Y = 0; XYZ_return.Z = 0; } else { /* * Make sure white point is in CIEXYZ form */ if (pxyY_WhitePt->format != XcmsCIEXYZFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)pxyY_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEXYZFormat)) { return(XcmsFailure); } pxyY_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (pxyY_WhitePt->spec.CIEXYZ.Y != 1.0) { return(XcmsFailure); } /* Convert from xyY to uvY to XYZ */ u = (4 * pColor->spec.CIExyY.x) / div; v = (9 * pColor->spec.CIExyY.y) / div; div = (6.0 * u) - (16.0 * v) + 12.0; if (div == 0.0) { /* Note that the divisor is zero */ /* This return is abitrary. */ if ((div = (6.0 * whitePt.spec.CIEuvY.u_prime) - (16.0 * whitePt.spec.CIEuvY.v_prime) + 12.0) == 0.0) { div = EPS; } x = 9.0 * whitePt.spec.CIEuvY.u_prime / div; y = 4.0 * whitePt.spec.CIEuvY.u_prime / div; } else { /* convert u, v to small xyz */ x = 9.0 * u / div; y = 4.0 * v / div; } z = 1.0 - x - y; if (y == 0.0) y = EPS; /* Have to worry about divide by 0 */ XYZ_return.Y = pColor->spec.CIExyY.Y; XYZ_return.X = x * XYZ_return.Y / y; XYZ_return.Z = z * XYZ_return.Y / y; } /* Copy result to pColor */ memcpy ((char *)&pColor->spec, (char *)&XYZ_return, sizeof(XcmsCIEXYZ)); /* Identify that the format is now CIEXYZ */ pColor->format = XcmsCIEXYZFormat; } return(XcmsSuccess); } /* * NAME * XcmsCIEXYZToCIExyY - convert CIEXYZ to CIExyY * * SYNOPSIS */ /* ARGSUSED */ Status XcmsCIEXYZToCIExyY(ccc, pxyY_WhitePt, pColors_in_out, nColors) XcmsCCC ccc; XcmsColor *pxyY_WhitePt; XcmsColor *pColors_in_out; unsigned int nColors; /* * DESCRIPTION * Converts color specifications in an array of XcmsColor * structures from CIEXYZ format to CIExyY format. * * RETURNS * XcmsFailure if failed, * XcmsSuccess if succeeded. * */ { XcmsColor *pColor = pColors_in_out; XcmsCIExyY xyY_return; XcmsFloat div; /* temporary storage in case divisor is zero */ register int i; /* * Check arguments * pxyY_WhitePt ignored */ if (pColors_in_out == NULL) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEXYZ form */ for (i = 0; i < nColors; i++, pColor++) { if (!_XcmsCIEXYZ_ValidSpec(pColor)) { return(XcmsFailure); } /* Now convert for XYZ to xyY */ if ((div = pColor->spec.CIEXYZ.X + pColor->spec.CIEXYZ.Y + pColor->spec.CIEXYZ.Z) == 0.0) { div = EPS; } xyY_return.x = pColor->spec.CIEXYZ.X / div; xyY_return.y = pColor->spec.CIEXYZ.Y / div; xyY_return.Y = pColor->spec.CIEXYZ.Y; /* Copy result to pColor */ memcpy ((char *)&pColor->spec, (char *)&xyY_return, sizeof(XcmsCIExyY)); /* Identify that the format is now CIEXYZ */ pColor->format = XcmsCIExyYFormat; } return(XcmsSuccess); }