src/cpml/cpml-utils.c

   1 /* CPML - Cairo Path Manipulation Library
   2  * Copyright (C) 2007-2021  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-utils
  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  * Since: 1.0
  30  **/
  31
  32
  33 #include "cpml-internal.h"
  34 #include <math.h>
  35
  36
  37 /**
  38  * cpml_angle:
  39  * @angle: an angle in radians
  40  *
  41  * Normalizes @angle, that is returns the equivalent radians value
  42  * between the range <constant>M_PI</constant> (inclusive)
  43  * and <constant>-M_PI</constant> (exclusive).
  44  *
  45  * Returns: an equivalent value in radians
  46  *
  47  * Since: 1.0
  48  **/
  49 double
  50 cpml_angle(double angle)
  51 {
  52     while (angle > M_PI)
  53         angle -= M_PI * 2;
  54
  55     while (angle <= -M_PI)
  56         angle += M_PI * 2;
  57
  58     return angle;
  59 }
  60
  61 /**
  62  * cpml_angle_distance:
  63  * @angle: first angle in radians
  64  * @from: second angle in radians
  65  *
  66  * Computes the distance between the two given angles. The returned
  67  * distance is always positive and is never greater than M_PI.
  68  *
  69  * Returns: the distance in radians
  70  *
  71  * Since: 1.0
  72  **/
  73 double
  74 cpml_angle_distance(double angle, double from)
  75 {
  76     double delta = cpml_angle(from - angle);
  77     return fabs(delta);
  78 }