qwt_math.h
/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
* Qwt Widget Library
* Copyright (C) 1997 Josef Wilgen
* Copyright (C) 2002 Uwe Rathmann
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the Qwt License, Version 1.0
*****************************************************************************/
#ifndef QWT_MATH_H
#define QWT_MATH_H
#include "qwt_global.h"
#if defined(_MSC_VER)
/*
Microsoft says:
Define _USE_MATH_DEFINES before including math.h to expose these macro
definitions for common math constants. These are placed under an #ifdef
since these commonly-defined names are not part of the C/C++ standards.
*/
#define _USE_MATH_DEFINES 1
#endif
#include <qmath.h>
#include "qwt_global.h"
#ifndef M_PI_2
// For Qt <= 4.8.4 M_PI_2 is not known by MinGW-w64
// when compiling with -std=c++11
#define M_PI_2 (1.57079632679489661923)
#endif
#ifndef LOG_MIN
#define LOG_MIN 1.0e-100
#endif
#ifndef LOG_MAX
#define LOG_MAX 1.0e100
#endif
QWT_EXPORT double qwtGetMin( const double *array, int size );
QWT_EXPORT double qwtGetMax( const double *array, int size );
QWT_EXPORT double qwtNormalizeRadians( double radians );
QWT_EXPORT double qwtNormalizeDegrees( double degrees );
inline int qwtFuzzyCompare( double value1, double value2, double intervalSize )
{
const double eps = qAbs( 1.0e-6 * intervalSize );
if ( value2 - value1 > eps )
return -1;
if ( value1 - value2 > eps )
return 1;
return 0;
}
inline bool qwtFuzzyGreaterOrEqual( double d1, double d2 )
{
return ( d1 >= d2 ) || qFuzzyCompare( d1, d2 );
}
inline bool qwtFuzzyLessOrEqual( double d1, double d2 )
{
return ( d1 <= d2 ) || qFuzzyCompare( d1, d2 );
}
inline int qwtSign( double x )
{
if ( x > 0.0 )
return 1;
else if ( x < 0.0 )
return ( -1 );
else
return 0;
}
inline double qwtSqr( double x )
{
return x * x;
}
inline double qwtFastAtan( double x )
{
if ( x < -1.0 )
return -M_PI_2 - x / ( x * x + 0.28 );
if ( x > 1.0 )
return M_PI_2 - x / ( x * x + 0.28 );
return x / ( 1.0 + x * x * 0.28 );
}
inline double qwtFastAtan2( double y, double x )
{
if ( x > 0 )
return qwtFastAtan( y / x );
if ( x < 0 )
{
const double d = qwtFastAtan( y / x );
return ( y >= 0 ) ? d + M_PI : d - M_PI;
}
if ( y < 0.0 )
return -M_PI_2;
if ( y > 0.0 )
return M_PI_2;
return 0.0;
}
inline double qwtRadians( double degrees )
{
return degrees * M_PI / 180.0;
}
inline double qwtDegrees( double degrees )
{
return degrees * 180.0 / M_PI;
}
#endif