Qwt User's Guide: qwt_math.h Source File

Qwt User's Guide 5.2.3

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qwt_math.h
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 <math.h>
14 #include <qpoint.h>
15 #include "qwt_global.h"
16 #include "qwt_double_rect.h"
17
18 #if QT_VERSION < 0x040000
19
20 #define qwtMax QMAX
21 #define qwtMin QMIN
22 #define qwtAbs QABS
23
24 #else // QT_VERSION >= 0x040000
25
26 #define qwtMax qMax
27 #define qwtMin qMin
28 #define qwtAbs qAbs
29
30 #endif
31
32 #ifndef LOG10_2
33 #define LOG10_2 0.30102999566398119802 /* log10(2) */
34 #endif
35
36 #ifndef LOG10_3
37 #define LOG10_3 0.47712125471966243540 /* log10(3) */
38 #endif
39
40 #ifndef LOG10_5
41 #define LOG10_5 0.69897000433601885749 /* log10(5) */
42 #endif
43
44 #ifndef M_2PI
45 #define M_2PI 6.28318530717958623200 /* 2 pi */
46 #endif
47
48 #ifndef LOG_MIN
49
50 #define LOG_MIN 1.0e-100
51 #endif
52
53 #ifndef LOG_MAX
54
55 #define LOG_MAX 1.0e100
56 #endif
57
58 #ifndef M_E
59 #define M_E 2.7182818284590452354 /* e */
60 #endif
61
62 #ifndef M_LOG2E
63 #define M_LOG2E 1.4426950408889634074 /* log_2 e */
64 #endif
65
66 #ifndef M_LOG10E
67 #define M_LOG10E 0.43429448190325182765 /* log_10 e */
68 #endif
69
70 #ifndef M_LN2
71 #define M_LN2 0.69314718055994530942 /* log_e 2 */
72 #endif
73
74 #ifndef M_LN10
75 #define M_LN10 2.30258509299404568402 /* log_e 10 */
76 #endif
77
78 #ifndef M_PI
79 #define M_PI 3.14159265358979323846 /* pi */
80 #endif
81
82 #ifndef M_PI_2
83 #define M_PI_2 1.57079632679489661923 /* pi/2 */
84 #endif
85
86 #ifndef M_PI_4
87 #define M_PI_4 0.78539816339744830962 /* pi/4 */
88 #endif
89
90 #ifndef M_1_PI
91 #define M_1_PI 0.31830988618379067154 /* 1/pi */
92 #endif
93
94 #ifndef M_2_PI
95 #define M_2_PI 0.63661977236758134308 /* 2/pi */
96 #endif
97
98 #ifndef M_2_SQRTPI
99 #define M_2_SQRTPI 1.12837916709551257390 /* 2/sqrt(pi) */
100 #endif
101
102 #ifndef M_SQRT2
103 #define M_SQRT2 1.41421356237309504880 /* sqrt(2) */
104 #endif
105
106 #ifndef M_SQRT1_2
107 #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
108 #endif
109
110 QWT_EXPORT double qwtGetMin(const double *array, int size);
111 QWT_EXPORT double qwtGetMax(const double *array, int size);
112
113
115 inline int qwtSign(double x)
116 {
117 if (x > 0.0)
118 return 1;
119 else if (x < 0.0)
120 return (-1);
121 else
122 return 0;
123 }
124
126 inline double qwtSqr(const double x)
127 {
128 return x*x;
129 }
130
137 template <class T>
138 T qwtLim(const T& x, const T& x1, const T& x2)
139 {
140 T rv;
141 T xmin, xmax;
142
143 xmin = qwtMin(x1, x2);
144 xmax = qwtMax(x1, x2);
145
146 if ( x < xmin )
147 rv = xmin;
148 else if ( x > xmax )
149 rv = xmax;
150 else
151 rv = x;
152
153 return rv;
154 }
155
156 inline QPoint qwtPolar2Pos(const QPoint &pole,
157 double radius, double angle)
158 {
159 const double x = pole.x() + radius * ::cos(angle);
160 const double y = pole.y() - radius * ::sin(angle);
161
162 return QPoint(qRound(x), qRound(y));
163 }
164
165 inline QPoint qwtDegree2Pos(const QPoint &pole,
166 double radius, double angle)
167 {
168 return qwtPolar2Pos(pole, radius, angle / 180.0 * M_PI);
169 }
170
171 inline QwtDoublePoint qwtPolar2Pos(const QwtDoublePoint &pole,
172 double radius, double angle)
173 {
174 const double x = pole.x() + radius * ::cos(angle);
175 const double y = pole.y() - radius * ::sin(angle);
176
177 return QPoint(qRound(x), qRound(y));
178 }
179
180 inline QwtDoublePoint qwtDegree2Pos(const QwtDoublePoint &pole,
181 double radius, double angle)
182 {
183 return qwtPolar2Pos(pole, radius, angle / 180.0 * M_PI);
184 }
185
187 inline double qwtRound(double value)
188 {
189 return ::floor(value + 0.5); // MSVC has no ::round().
190 }
191
192 #endif