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/* 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
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