flower/offset.cc

   1 /*
   2   offset.cc -- implement Offset
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "offset.hh"
  10
  11 #ifndef STANDALONE
  12 string
  13 Offset::to_string () const
  14 {
  15   string s;
  16   s = string (" (") + ::to_string (coordinate_a_[X_AXIS]) + ", "
  17     + ::to_string (coordinate_a_[Y_AXIS]) + ")";
  18   return s;
  19 }
  20 #endif
  21
  22 /*
  23   free bsd fix by John Galbraith
  24 */
  25
  26 Offset
  27 complex_multiply (Offset z1, Offset z2)
  28 {
  29   Offset z;
  30   if (!isinf (z2[Y_AXIS]))
  31     {
  32       z[X_AXIS] = z1[X_AXIS] * z2[X_AXIS] - z1[Y_AXIS] * z2[Y_AXIS];
  33       z[Y_AXIS] = z1[X_AXIS] * z2[Y_AXIS] + z1[Y_AXIS] * z2[X_AXIS];
  34     }
  35   return z;
  36 }
  37
  38 Offset
  39 complex_conjugate (Offset o)
  40 {
  41   o[Y_AXIS] = -o[Y_AXIS];
  42   return o;
  43 }
  44
  45 Offset
  46 complex_divide (Offset z1, Offset z2)
  47 {
  48   z2 = complex_conjugate (z2);
  49   Offset z = complex_multiply (z1, z2);
  50   z *= 1 / z2.length ();
  51   return z;
  52 }
  53
  54 Offset
  55 complex_exp (Offset o)
  56 {
  57   Real s = sin (o[Y_AXIS]);
  58   Real c = cos (o[Y_AXIS]);
  59
  60   Real r = exp (o[X_AXIS]);
  61
  62   return Offset (r * c, r * s);
  63 }
  64
  65 Real
  66 Offset::arg () const
  67 {
  68   return atan2 (coordinate_a_[Y_AXIS], coordinate_a_[X_AXIS]);
  69 }
  70
  71 Real
  72 Offset::angle_degrees () const
  73 {
  74   return arg () * 180 / M_PI;
  75 }
  76 /**
  77    euclidian vector length / complex modulus
  78 */
  79 Real
  80 Offset::length () const
  81 {
  82   return sqrt (sqr (coordinate_a_[X_AXIS])
  83                     + sqr (coordinate_a_[Y_AXIS]));
  84 }
  85
  86 bool
  87 Offset::is_sane () const
  88 {
  89   return !isnan (coordinate_a_[X_AXIS])
  90     && !isnan (coordinate_a_ [Y_AXIS])
  91     && !isinf (coordinate_a_[X_AXIS])
  92     && !isinf (coordinate_a_[Y_AXIS]);
  93 }
  94
  95 Offset
  96 Offset::direction () const
  97 {
  98   Offset d = *this;
  99   d /= length ();
 100   return d;
 101 }
 102
 103 Offset
 104 Offset::swapped () const
 105 {
 106   return Offset (coordinate_a_[Y_AXIS], coordinate_a_[X_AXIS]);
 107 }