新增qwt源码版本

qwtdemo/qwt/qwt_math.cpp

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+/* -*- 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
+ *****************************************************************************/
+
+#include "qwt_math.h"
+
+/*!
+  \brief Find the smallest value in an array
+  \param array Pointer to an array
+  \param size Array size
+*/
+double qwtGetMin( const double *array, int size )
+{
+    if ( size <= 0 )
+        return 0.0;
+
+    double rv = array[0];
+    for ( int i = 1; i < size; i++ )
+        rv = qMin( rv, array[i] );
+
+    return rv;
+}
+
+
+/*!
+  \brief Find the largest value in an array
+  \param array Pointer to an array
+  \param size Array size
+*/
+double qwtGetMax( const double *array, int size )
+{
+    if ( size <= 0 )
+        return 0.0;
+
+    double rv = array[0];
+    for ( int i = 1; i < size; i++ )
+        rv = qMax( rv, array[i] );
+
+    return rv;
+}
+
+/*!
+  \brief Normalize an angle to be int the range [0.0, 2 * PI[
+  \param radians Angle in radians
+  \return Normalized angle in radians
+*/
+double qwtNormalizeRadians( double radians )
+{
+    double a = ::fmod( radians, 2.0 * M_PI );
+    if ( a < 0.0 )
+        a += 2.0 * M_PI;
+
+    return a;
+
+}
+
+/*!
+  \brief Normalize an angle to be int the range [0.0, 360.0[
+  \param radians Angle in degrees
+  \return Normalized angle in degrees
+*/
+double qwtNormalizeDegrees( double degrees )
+{
+    double a = ::fmod( degrees, 360.0 );
+    if ( a < 0.0 )
+        a += 360.0;
+
+    return a;
+}