/* $Xorg: HVC.c,v 1.3 2000/08/17 19:44:36 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. TekColor is a * trademark of Tektronix, Inc. The term "TekHVC" designates a particular * color space that is the subject of U.S. Patent No. 4,985,853 (equivalent * foreign patents pending). 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: * * 1. This copyright, permission, and disclaimer notice is reproduced in * all copies of this software and any modification thereof and in * supporting documentation; * 2. Any color-handling application which displays TekHVC color * cooordinates identifies these as TekHVC color coordinates in any * interface that displays these coordinates and in any associated * documentation; * 3. The term "TekHVC" is always used, and is only used, in association * with the mathematical derivations of the TekHVC Color Space, * including those provided in this file and any equivalent pathways and * mathematical derivations, regardless of digital (e.g., floating point * or integer) representation. * * 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 * TekHVC.c * * DESCRIPTION * This file contains routines that support the TekHVC * 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/HVC.c,v 1.3 2001/01/17 19:41:37 dawes Exp $ */ #include "Xlibint.h" #include "Xcmsint.h" #include #include #include /* * DEFINES */ #define u_BR 0.7127 /* u' Best Red */ #define v_BR 0.4931 /* v' Best Red */ #define EPS 0.001 #define CHROMA_SCALE_FACTOR 7.50725 #ifndef PI # ifdef M_PI # define PI M_PI # else # define PI 3.14159265358979323846264338327950 # endif #endif #ifndef degrees # define degrees(r) ((XcmsFloat)(r) * 180.0 / PI) #endif /* degrees */ #ifndef radians # define radians(d) ((XcmsFloat)(d) * PI / 180.0) #endif /* radians */ /************************************************************************* * Note: The DBL_EPSILON for ANSI is 1e-5 so my checks need to take * this into account. If your DBL_EPSILON is different then * adjust this define. * * Also note that EPS is the error factor in the calculations * This may need to be the same as XMY_DBL_EPSILON in * some implementations. **************************************************************************/ #ifdef DBL_EPSILON # define XMY_DBL_EPSILON DBL_EPSILON #else # define XMY_DBL_EPSILON 0.00001 #endif /* * EXTERNS */ extern char _XcmsTekHVC_prefix[]; /* CvCols.c */ extern Status _XcmsDIConvertColors(); /* uvY.c */ extern Status _XcmsCIEuvY_ValidSpec(); /* * FORWARD DECLARATIONS */ static int TekHVC_ParseString(); static Status XcmsTekHVC_ValidSpec(); /* * LOCAL VARIABLES */ /* * NULL terminated list of functions applied to get from TekHVC to CIEXYZ */ static XcmsConversionProc Fl_TekHVC_to_CIEXYZ[] = { XcmsTekHVCToCIEuvY, XcmsCIEuvYToCIEXYZ, NULL }; /* * NULL terminated list of functions applied to get from CIEXYZ to TekHVC */ static XcmsConversionProc Fl_CIEXYZ_to_TekHVC[] = { XcmsCIEXYZToCIEuvY, XcmsCIEuvYToTekHVC, NULL }; /* * GLOBALS */ /* * TekHVC Color Space */ XcmsColorSpace XcmsTekHVCColorSpace = { _XcmsTekHVC_prefix, /* prefix */ XcmsTekHVCFormat, /* id */ TekHVC_ParseString, /* parseString */ Fl_TekHVC_to_CIEXYZ, /* to_CIEXYZ */ Fl_CIEXYZ_to_TekHVC, /* from_CIEXYZ */ 1 }; /************************************************************************ * * * PRIVATE ROUTINES * * * ************************************************************************/ /* * NAME * TekHVC_ParseString * * SYNOPSIS */ static int TekHVC_ParseString(spec, pColor) register char *spec; XcmsColor *pColor; /* * DESCRIPTION * This routines takes a string and attempts to convert * it into a XcmsColor structure with XcmsTekHVCFormat. * The assumed TekHVC string syntax is: * TekHVC:// * Where H, V, and C 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 * XcmsFailure if invalid; * XcmsSuccess if valid. */ { int n; char *pchar; if ((pchar = strchr(spec, ':')) == NULL) { return(XcmsFailure); } n = (int)(pchar - spec); /* * Check for proper prefix. */ if (strncmp(spec, _XcmsTekHVC_prefix, n) != 0) { return(XcmsFailure); } /* * Attempt to parse the value portion. */ if (sscanf(spec + n + 1, "%lf/%lf/%lf", &pColor->spec.TekHVC.H, &pColor->spec.TekHVC.V, &pColor->spec.TekHVC.C) != 3) { return(XcmsFailure); } pColor->format = XcmsTekHVCFormat; pColor->pixel = 0; return(XcmsTekHVC_ValidSpec(pColor)); } /* * NAME * ThetaOffset -- compute thetaOffset * * SYNOPSIS */ static int ThetaOffset(pWhitePt, pThetaOffset) XcmsColor *pWhitePt; XcmsFloat *pThetaOffset; /* * DESCRIPTION * This routine computes the theta offset of a given * white point, i.e. XcmsColor. It is used in both this * conversion and the printer conversions. * * RETURNS * 0 if failed. * 1 if succeeded with no modifications. * * ASSUMPTIONS * Assumes: * pWhitePt != NULL * pWhitePt->format == XcmsCIEuvYFormat * */ { double div, slopeuv; if (pWhitePt == NULL || pWhitePt->format != XcmsCIEuvYFormat) { return(0); } if ((div = u_BR - pWhitePt->spec.CIEuvY.u_prime) == 0.0) { return(0); } slopeuv = (v_BR - pWhitePt->spec.CIEuvY.v_prime) / div; *pThetaOffset = degrees(XCMS_ATAN(slopeuv)); return(1); } /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * XcmsTekHVC_ValidSpec() * * SYNOPSIS */ static int XcmsTekHVC_ValidSpec(pColor) XcmsColor *pColor; /* * DESCRIPTION * Checks if values in the color specification are valid. * Also brings hue into the range 0.0 <= Hue < 360.0 * * RETURNS * 0 if not valid. * 1 if valid. * */ { if (pColor->format != XcmsTekHVCFormat) { return(XcmsFailure); } if (pColor->spec.TekHVC.V < (0.0 - XMY_DBL_EPSILON) || pColor->spec.TekHVC.V > (100.0 + XMY_DBL_EPSILON) || (pColor->spec.TekHVC.C < 0.0 - XMY_DBL_EPSILON)) { return(XcmsFailure); } if (pColor->spec.TekHVC.V < 0.0) { pColor->spec.TekHVC.V = 0.0 + XMY_DBL_EPSILON; } else if (pColor->spec.TekHVC.V > 100.0) { pColor->spec.TekHVC.V = 100.0 - XMY_DBL_EPSILON; } if (pColor->spec.TekHVC.C < 0.0) { pColor->spec.TekHVC.C = 0.0 - XMY_DBL_EPSILON; } while (pColor->spec.TekHVC.H < 0.0) { pColor->spec.TekHVC.H += 360.0; } while (pColor->spec.TekHVC.H >= 360.0) { pColor->spec.TekHVC.H -= 360.0; } return(XcmsSuccess); } /* * NAME * XcmsTekHVCToCIEuvY - convert TekHVC to CIEuvY * * SYNOPSIS */ Status XcmsTekHVCToCIEuvY(ccc, pHVC_WhitePt, pColors_in_out, nColors) XcmsCCC ccc; XcmsColor *pHVC_WhitePt; XcmsColor *pColors_in_out; unsigned int nColors; /* * DESCRIPTION * Transforms an array of TekHVC color specifications, given * their associated white point, to CIECIEuvY.color * specifications. * * RETURNS * XcmsFailure if failed, XcmsSuccess otherwise. * */ { XcmsFloat thetaOffset; XcmsColor *pColor = pColors_in_out; XcmsColor whitePt; XcmsCIEuvY uvY_return; XcmsFloat tempHue, u, v; XcmsFloat tmpVal; register int i; /* * Check arguments */ if (pHVC_WhitePt == NULL || pColors_in_out == NULL) { return(XcmsFailure); } /* * Make sure white point is in CIEuvY form */ if (pHVC_WhitePt->format != XcmsCIEuvYFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)pHVC_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { return(XcmsFailure); } pHVC_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (pHVC_WhitePt->spec.CIEuvY.Y != 1.0) { return(XcmsFailure); } /* Get the thetaOffset */ if (!ThetaOffset(pHVC_WhitePt, &thetaOffset)) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEXYZ form */ for (i = 0; i < nColors; i++, pColor++) { /* Make sure original format is TekHVC and is valid */ if (!XcmsTekHVC_ValidSpec(pColor)) { return(XcmsFailure); } if (pColor->spec.TekHVC.V == 0.0 || pColor->spec.TekHVC.V == 100.0) { if (pColor->spec.TekHVC.V == 100.0) { uvY_return.Y = 1.0; } else { /* pColor->spec.TekHVC.V == 0.0 */ uvY_return.Y = 0.0; } uvY_return.u_prime = pHVC_WhitePt->spec.CIEuvY.u_prime; uvY_return.v_prime = pHVC_WhitePt->spec.CIEuvY.v_prime; } else { /* Find the hue based on the white point offset */ tempHue = pColor->spec.TekHVC.H + thetaOffset; while (tempHue < 0.0) { tempHue += 360.0; } while (tempHue >= 360.0) { tempHue -= 360.0; } tempHue = radians(tempHue); /* Calculate u'v' for the obtained hue */ u = (XcmsFloat) ((XCMS_COS(tempHue) * pColor->spec.TekHVC.C) / (pColor->spec.TekHVC.V * (double)CHROMA_SCALE_FACTOR)); v = (XcmsFloat) ((XCMS_SIN(tempHue) * pColor->spec.TekHVC.C) / (pColor->spec.TekHVC.V * (double)CHROMA_SCALE_FACTOR)); /* Based on the white point get the offset from best red */ uvY_return.u_prime = u + pHVC_WhitePt->spec.CIEuvY.u_prime; uvY_return.v_prime = v + pHVC_WhitePt->spec.CIEuvY.v_prime; /* Calculate the Y value based on the L* = V. */ if (pColor->spec.TekHVC.V < 7.99953624) { uvY_return.Y = pColor->spec.TekHVC.V / 903.29; } else { tmpVal = (pColor->spec.TekHVC.V + 16.0) / 116.0; uvY_return.Y = tmpVal * tmpVal * tmpVal; /* tmpVal ** 3 */ } } /* 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 * XcmsCIEuvYToTekHVC - convert CIEuvY to TekHVC * * SYNOPSIS */ Status XcmsCIEuvYToTekHVC(ccc, pHVC_WhitePt, pColors_in_out, nColors) XcmsCCC ccc; XcmsColor *pHVC_WhitePt; XcmsColor *pColors_in_out; unsigned int nColors; /* * DESCRIPTION * Transforms an array of CIECIEuvY.color specifications, given * their assiciated white point, to TekHVC specifications. * * RETURNS * XcmsFailure if failed, XcmsSuccess otherwise. * */ { XcmsFloat theta, L2, u, v, nThetaLow, nThetaHigh; XcmsFloat thetaOffset; XcmsColor *pColor = pColors_in_out; XcmsColor whitePt; XcmsTekHVC HVC_return; register int i; /* * Check arguments */ if (pHVC_WhitePt == NULL || pColors_in_out == NULL) { return(XcmsFailure); } /* * Make sure white point is in CIEuvY form */ if (pHVC_WhitePt->format != XcmsCIEuvYFormat) { /* Make copy of the white point because we're going to modify it */ memcpy((char *)&whitePt, (char *)pHVC_WhitePt, sizeof(XcmsColor)); if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { return(XcmsFailure); } pHVC_WhitePt = &whitePt; } /* Make sure it is a white point, i.e., Y == 1.0 */ if (pHVC_WhitePt->spec.CIEuvY.Y != 1.0) { return(XcmsFailure); } if (!ThetaOffset(pHVC_WhitePt, &thetaOffset)) { return(XcmsFailure); } /* * Now convert each XcmsColor structure to CIEXYZ form */ for (i = 0; i < nColors; i++, pColor++) { if (!_XcmsCIEuvY_ValidSpec(pColor)) { return(XcmsFailure); } /* Use the white point offset to determine HVC */ u = pColor->spec.CIEuvY.u_prime - pHVC_WhitePt->spec.CIEuvY.u_prime; v = pColor->spec.CIEuvY.v_prime - pHVC_WhitePt->spec.CIEuvY.v_prime; /* Calculate the offset */ if (u == 0.0) { theta = 0.0; } else { theta = v / u; theta = (XcmsFloat) XCMS_ATAN((double)theta); theta = degrees(theta); } nThetaLow = 0.0; nThetaHigh = 360.0; if (u > 0.0 && v > 0.0) { nThetaLow = 0.0; nThetaHigh = 90.0; } else if (u < 0.0 && v > 0.0) { nThetaLow = 90.0; nThetaHigh = 180.0; } else if (u < 0.0 && v < 0.0) { nThetaLow = 180.0; nThetaHigh = 270.0; } else if (u > 0.0 && v < 0.0) { nThetaLow = 270.0; nThetaHigh = 360.0; } while (theta < nThetaLow) { theta += 90.0; } while (theta >= nThetaHigh) { theta -= 90.0; } /* calculate the L value from the given Y */ L2 = (pColor->spec.CIEuvY.Y < 0.008856) ? (pColor->spec.CIEuvY.Y * 903.29) : ((XcmsFloat)(XCMS_CUBEROOT(pColor->spec.CIEuvY.Y) * 116.0) - 16.0); HVC_return.C = L2 * CHROMA_SCALE_FACTOR * XCMS_SQRT((double) ((u * u) + (v * v))); if (HVC_return.C < 0.0) { theta = 0.0; } HVC_return.V = L2; HVC_return.H = theta - thetaOffset; /* * If this is within the error margin let some other routine later * in the chain worry about the slop in the calculations. */ while (HVC_return.H < -EPS) { HVC_return.H += 360.0; } while (HVC_return.H >= 360.0 + EPS) { HVC_return.H -= 360.0; } /* Copy result to pColor */ memcpy((char *)&pColor->spec, (char *)&HVC_return, sizeof(XcmsTekHVC)); /* Identify that the format is now CIEuvY */ pColor->format = XcmsTekHVCFormat; } return(XcmsSuccess); } /* * NAME * _XcmsTekHVC_CheckModify * * SYNOPSIS */ int _XcmsTekHVC_CheckModify(pColor) XcmsColor *pColor; /* * DESCRIPTION * Checks if values in the color specification are valid. * If they are not it modifies the values. * Also brings hue into the range 0.0 <= Hue < 360.0 * * RETURNS * 0 if not valid. * 1 if valid. * */ { int n; /* For now only use the TekHVC numbers as inputs */ if (pColor->format != XcmsTekHVCFormat) { return(0); } if (pColor->spec.TekHVC.V < 0.0) { pColor->spec.TekHVC.V = 0.0 + XMY_DBL_EPSILON; } else if (pColor->spec.TekHVC.V > 100.0) { pColor->spec.TekHVC.V = 100.0 - XMY_DBL_EPSILON; } if (pColor->spec.TekHVC.C < 0.0) { pColor->spec.TekHVC.C = 0.0 - XMY_DBL_EPSILON; } if (pColor->spec.TekHVC.H < 0.0) { n = -pColor->spec.TekHVC.H / 360.0; pColor->spec.TekHVC.H += (n + 1) * 360.0; if (pColor->spec.TekHVC.H >= 360.0) pColor->spec.TekHVC.H -= 360.0; } else if (pColor->spec.TekHVC.H >= 360.0) { n = pColor->spec.TekHVC.H / 360.0; pColor->spec.TekHVC.H -= n * 360.0; } return(1); }