cpml/cpml-util.c

   1 /* CPML - Cairo Path Manipulation Library
   2  * Copyright (C) 2008,2009,2010  Nicola Fontana <ntd at entidi.it>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:cpml-util
  23  * @Section_Id:utilities
  24  * @title: Utilities
  25  * @short_description: Assorted macros and functions
  26  *
  27  * Collection of macros and functions that do not fit inside any other topic.
  28  **/
  29
  30
  31 #include "cpml-internal.h"
  32 #include <math.h>
  33
  34
  35 /**
  36  * CPML_GNUC_CONST:
  37  *
  38  * To be appended at the end of a function to notice the compiler (gcc)
  39  * that the return value is constant.
  40  *
  41  * The coded is an adaptation of the #G_GNUC_CONST macro defined by
  42  * glib-2.18.3 in <filename>glib/gmacros.h</filename>.
  43  **/
  44
  45
  46 /**
  47  * cpml_angle:
  48  * @angle: an angle in radians
  49  *
  50  * Normalizes @angle, that is returns the equivalent radians value
  51  * between the range %M_PI (inclusive) and %-M_PI (exclusive).
  52  *
  53  * Returns: an equivalent value in radians
  54  **/
  55 double
  56 cpml_angle(double angle)
  57 {
  58     while (angle > M_PI)
  59         angle -= M_PI * 2;
  60
  61     while (angle <= -M_PI)
  62         angle += M_PI * 2;
  63
  64     return angle;
  65 }