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Diffstat (limited to 'karbon/core/vglobal.h')
-rw-r--r-- | karbon/core/vglobal.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/karbon/core/vglobal.h b/karbon/core/vglobal.h new file mode 100644 index 00000000..c20d48b0 --- /dev/null +++ b/karbon/core/vglobal.h @@ -0,0 +1,109 @@ +/* This file is part of the KDE project + Copyright (C) 2001, The Karbon Developers + Copyright (C) 2002, The Karbon Developers + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public License + along with this library; see the file COPYING.LIB. If not, write to + the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301, USA. +*/ + +#ifndef __VGLOBAL_H__ +#define __VGLOBAL_H__ + +#include <kglobal.h> + +// define some often used mathematical constants et al: + +// TODO: optimize those values. + +namespace VGlobal +{ + const double pi = 3.14159265358979323846; // pi + const double twopi = 6.28318530717958647692; // 2pi + const double pi_2 = 1.57079632679489661923; // pi/2 + const double pi_180 = 0.01745329251994329576; // pi/180 + const double one_pi_180 = 57.29577951308232087684; // 180/pi + const double sqrt2 = 1.41421356237309504880; // sqrt(2) + const double one_3 = 0.33333333333333333333; // 1/3 + const double two_3 = 0.66666666666666666667; // 2/3 + const double one_6 = 0.16666666666666666667; // 1/6 + const double one_7 = 0.14285714285714285714; // 1/7 + + /** + * Constants used to decide if a number is equal zero or nearly the same + * as another number. + */ + const double veryBigNumber = 1.0e8; + const double verySmallNumber = 1.0e-8; + + /** + * A bezier with this flatness is considered "flat". Used in subdividing. + */ + const double flatnessTolerance = 0.01; + + /** + * A tolerance used to approximate bezier lengths. If the relative difference + * between chordlength and polylength (length of the controlpolygon) is smaller + * than this value, the length of the bezier is 1/2 chordlength + 1/2 polylength. + */ + const double lengthTolerance = 0.005; + + /** + * A tolerance used to calculate param t on a segment at a given arc + * length (counting from t=0). + * If the relative difference between a length approximation and the given + * length is smaller than this value, they are assumed to be identical. + */ + const double paramLengthTolerance = 0.001; + + /** + * A range for KoPoint::isNear() check, to decide if a KoPoint "is the same" + * as another. + */ + const double isNearRange = 0.001; + + /** + * A tolerance for multiplying normalized (length=1) vectors. A result of + * >= parallelTolerance indicates parallel vectors. + */ + const double parallelTolerance = 0.99; + + /** + * Returns the sign of paramater a. + */ + inline int sign( double a ) + { + return a < 0.0 + ? -1 + : 1; + } + + /** + * Calculates the binomial coefficient n! / ( k! * ( n - k)! ). + */ + int binomialCoeff( unsigned n, unsigned k ); + + /** + * Calculates the value ln( n! ). + */ + double factorialLn( unsigned n ); + + /** + * Calculates the value ln| Gamma(x) | for x > 0. + */ + double gammaLn( double x ); +} + +#endif + |