source: ntrip/trunk/BNC/qwt/qwt_math.h@ 10496

Last change on this file since 10496 was 9383, checked in by stoecker, 4 years ago

update to qwt verion 6.1.1 to fix build with newer Qt5

File size: 3.3 KB
Line 
1/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
2 * Qwt Widget Library
3 * Copyright (C) 1997 Josef Wilgen
4 * Copyright (C) 2002 Uwe Rathmann
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the Qwt License, Version 1.0
8 *****************************************************************************/
9
10#ifndef QWT_MATH_H
11#define QWT_MATH_H
12
13#include "qwt_global.h"
14
15#if defined(_MSC_VER)
16/*
17 Microsoft says:
18
19 Define _USE_MATH_DEFINES before including math.h to expose these macro
20 definitions for common math constants. These are placed under an #ifdef
21 since these commonly-defined names are not part of the C/C++ standards.
22*/
23#define _USE_MATH_DEFINES 1
24#endif
25
26#include <qmath.h>
27#include "qwt_global.h"
28
29#ifndef M_PI_2
30// For Qt <= 4.8.4 M_PI_2 is not known by MinGW-w64
31// when compiling with -std=c++11
32#define M_PI_2 (1.57079632679489661923)
33#endif
34
35#ifndef LOG_MIN
36//! Minimum value for logarithmic scales
37#define LOG_MIN 1.0e-100
38#endif
39
40#ifndef LOG_MAX
41//! Maximum value for logarithmic scales
42#define LOG_MAX 1.0e100
43#endif
44
45QWT_EXPORT double qwtGetMin( const double *array, int size );
46QWT_EXPORT double qwtGetMax( const double *array, int size );
47
48QWT_EXPORT double qwtNormalizeRadians( double radians );
49QWT_EXPORT double qwtNormalizeDegrees( double degrees );
50
51/*!
52 \brief Compare 2 values, relative to an interval
53
54 Values are "equal", when :
55 \f$\cdot value2 - value1 <= abs(intervalSize * 10e^{-6})\f$
56
57 \param value1 First value to compare
58 \param value2 Second value to compare
59 \param intervalSize interval size
60
61 \return 0: if equal, -1: if value2 > value1, 1: if value1 > value2
62*/
63inline int qwtFuzzyCompare( double value1, double value2, double intervalSize )
64{
65 const double eps = qAbs( 1.0e-6 * intervalSize );
66
67 if ( value2 - value1 > eps )
68 return -1;
69
70 if ( value1 - value2 > eps )
71 return 1;
72
73 return 0;
74}
75
76
77inline bool qwtFuzzyGreaterOrEqual( double d1, double d2 )
78{
79 return ( d1 >= d2 ) || qFuzzyCompare( d1, d2 );
80}
81
82inline bool qwtFuzzyLessOrEqual( double d1, double d2 )
83{
84 return ( d1 <= d2 ) || qFuzzyCompare( d1, d2 );
85}
86
87//! Return the sign
88inline int qwtSign( double x )
89{
90 if ( x > 0.0 )
91 return 1;
92 else if ( x < 0.0 )
93 return ( -1 );
94 else
95 return 0;
96}
97
98//! Return the square of a number
99inline double qwtSqr( double x )
100{
101 return x * x;
102}
103
104//! Approximation of arc tangent ( error below 0,005 radians )
105inline double qwtFastAtan( double x )
106{
107 if ( x < -1.0 )
108 return -M_PI_2 - x / ( x * x + 0.28 );
109
110 if ( x > 1.0 )
111 return M_PI_2 - x / ( x * x + 0.28 );
112
113 return x / ( 1.0 + x * x * 0.28 );
114}
115
116//! Approximation of arc tangent ( error below 0,005 radians )
117inline double qwtFastAtan2( double y, double x )
118{
119 if ( x > 0 )
120 return qwtFastAtan( y / x );
121
122 if ( x < 0 )
123 {
124 const double d = qwtFastAtan( y / x );
125 return ( y >= 0 ) ? d + M_PI : d - M_PI;
126 }
127
128 if ( y < 0.0 )
129 return -M_PI_2;
130
131 if ( y > 0.0 )
132 return M_PI_2;
133
134 return 0.0;
135}
136
137//! Translate degrees into radians
138inline double qwtRadians( double degrees )
139{
140 return degrees * M_PI / 180.0;
141}
142
143//! Translate radians into degrees
144inline double qwtDegrees( double degrees )
145{
146 return degrees * 180.0 / M_PI;
147}
148
149#endif
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