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