/* * 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 * TekHVCMxV.c * * DESCRIPTION * Source for the XcmsTekHVCQueryMaxV() gamut boundary * querying routine. * */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "Xlibint.h" #include "Xcmsint.h" #include <math.h> #include "Cv.h" /* * DEFINES */ #define MAXBISECTCOUNT 100 #define EPS 0.001 /************************************************************************ * * * PUBLIC ROUTINES * * * ************************************************************************/ /* * NAME * XcmsTekHVCQueryMaxV - Compute maximum value for a hue and chroma * * SYNOPSIS */ Status XcmsTekHVCQueryMaxV( XcmsCCC ccc, XcmsFloat hue, XcmsFloat chroma, XcmsColor *pColor_return) /* * DESCRIPTION * Return the maximum value for a specified hue and chroma. * * ASSUMPTIONS * This routine assumes that the white point associated with * the color specification is the Screen White Point. The * Screen White Point will also be associated with the * returned color specification. * * RETURNS * XcmsFailure - Failure * XcmsSuccess - Succeeded with no modifications * */ { XcmsCCCRec myCCC; XcmsColor tmp; XcmsColor max_vc; XcmsRGBi rgb_saved; int nCount, nMaxCount; XcmsFloat nT, nChroma, savedChroma, lastValue, lastChroma, prevChroma; XcmsFloat rFactor; XcmsFloat ftmp1, ftmp2; /* * Check Arguments */ if (ccc == NULL || pColor_return == NULL) { return(XcmsFailure); } /* * Insure TekHVC installed */ if (XcmsAddColorSpace(&XcmsTekHVCColorSpace) == XcmsFailure) { return(XcmsFailure); } /* setup the CCC to use for the conversions. */ memcpy ((char *) &myCCC, (char *) ccc, sizeof(XcmsCCCRec)); myCCC.clientWhitePt.format = XcmsUndefinedFormat; myCCC.gamutCompProc = (XcmsCompressionProc) NULL; tmp.spec.TekHVC.H = hue; tmp.spec.TekHVC.V = 0.0; tmp.spec.TekHVC.C = chroma; tmp.pixel = pColor_return->pixel; tmp.format = XcmsTekHVCFormat; if (!_XcmsTekHVC_CheckModify (&tmp)) { return(XcmsFailure); } /* Step 1: compute the maximum value and chroma for this hue. */ /* This copy may be overkill but it preserves the pixel etc. */ memcpy((char *)&max_vc, (char *)&tmp, sizeof(XcmsColor)); hue = max_vc.spec.TekHVC.H; if (_XcmsTekHVCQueryMaxVCRGB(&myCCC, max_vc.spec.TekHVC.H, &max_vc, &rgb_saved) == XcmsFailure) { return(XcmsFailure); } if (max_vc.spec.TekHVC.C < tmp.spec.TekHVC.C) { /* * If the chroma is greater than the chroma for the * maximum value/chroma point then the value is the * the value for the maximum value, chroma point. * This is an error but it I return the best approximation I can. * Thus the inconsistency. */ tmp.spec.TekHVC.C = max_vc.spec.TekHVC.C; tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V; memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); return(XcmsSuccess); } else if (max_vc.spec.TekHVC.C == tmp.spec.TekHVC.C) { /* * If the chroma is equal to the chroma for the * maximum value/chroma point then the value is the * the value for the maximum value, chroma point. */ tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V; memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); return(XcmsSuccess); } else { /* must do a bisection here to compute the maximum value */ /* save the structure input so that any elements that */ /* are not touched are recopied later in the routine. */ nChroma = savedChroma = tmp.spec.TekHVC.C; tmp.spec.TekHVC.C = max_vc.spec.TekHVC.C; tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V; lastChroma = -1.0; lastValue = -1.0; nMaxCount = MAXBISECTCOUNT; rFactor = 1.0; for (nCount = 0; nCount < nMaxCount; nCount++) { prevChroma = lastChroma; lastValue = tmp.spec.TekHVC.V; lastChroma = tmp.spec.TekHVC.C; nT = (1.0 - (nChroma / max_vc.spec.TekHVC.C)) * rFactor; tmp.spec.RGBi.red = rgb_saved.red * (1.0 - nT) + nT; tmp.spec.RGBi.green = rgb_saved.green * (1.0 - nT) + nT; tmp.spec.RGBi.blue = rgb_saved.blue * (1.0 - nT) + nT; tmp.format = XcmsRGBiFormat; /* convert from RGB to HVC */ if (_XcmsConvertColorsWithWhitePt(&myCCC, &tmp, &myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsTekHVCFormat, (Bool *) NULL) == XcmsFailure) { return(XcmsFailure); } /* Now check the return against what is expected */ if (tmp.spec.TekHVC.C <= savedChroma + EPS && tmp.spec.TekHVC.C >= savedChroma - EPS) { tmp.spec.TekHVC.H = hue; /* use the saved hue */ memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); return(XcmsSuccess); } nChroma += savedChroma - tmp.spec.TekHVC.C; if (nChroma > max_vc.spec.TekHVC.C) { nChroma = max_vc.spec.TekHVC.C; rFactor *= 0.5; /* selective relaxation employed */ } else if (nChroma < 0.0) { /* avoid using fabs */ ftmp1 = lastChroma - savedChroma; if (ftmp1 < 0.0) ftmp1 = -ftmp1; ftmp2 = tmp.spec.TekHVC.C - savedChroma; if (ftmp2 < 0.0) ftmp2 = -ftmp2; if (ftmp1 < ftmp2) { tmp.spec.TekHVC.V = lastValue; tmp.spec.TekHVC.C = lastChroma; } /* make sure to return the input hue */ tmp.spec.TekHVC.H = hue; if (!_XcmsTekHVC_CheckModify(&tmp)) { return(XcmsFailure); } memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); return(XcmsSuccess); } else if (tmp.spec.TekHVC.C <= prevChroma + EPS && tmp.spec.TekHVC.C >= prevChroma - EPS) { rFactor *= 0.5; /* selective relaxation employed */ } } if (nCount >= nMaxCount) { /* avoid using fabs */ ftmp1 = lastChroma - savedChroma; if (ftmp1 < 0.0) ftmp1 = -ftmp1; ftmp2 = tmp.spec.TekHVC.C - savedChroma; if (ftmp2 < 0.0) ftmp2 = -ftmp2; if (ftmp1 < ftmp2) { tmp.spec.TekHVC.V = lastValue; tmp.spec.TekHVC.C = lastChroma; } } } /* make sure to return the input hue */ tmp.spec.TekHVC.H = hue; memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); return(XcmsSuccess); }