flower/offset.cc

   1 /*
   2   offset.cc -- implement Offset
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8 #include <math.h>
   9
  10 #ifndef STANDALONE
  11 #include "string.hh"
  12 #endif
  13 #include "offset.hh"
  14
  15
  16 #ifndef STANDALONE
  17 String
  18 Offset::str () const
  19 {
  20   String s;
  21   s = String("(") + to_str (coordinate_a_[X_AXIS]) + ", "
  22     + to_str (coordinate_a_[Y_AXIS]) + ")";
  23   return s;
  24 }
  25 #endif
  26
  27
  28 bool
  29 isinf_b (Real r)
  30 {
  31   return (fabs (r) > 1e20);
  32 }
  33
  34 /*
  35   free bsd fix by John Galbraith
  36  */
  37
  38 Offset
  39 complex_multiply (Offset z1, Offset z2)
  40 {
  41   Offset z;
  42   if(!isinf_b(z2[Y_AXIS]))
  43   {
  44       z[X_AXIS] = z1[X_AXIS] * z2[X_AXIS] - z1[Y_AXIS]*z2[Y_AXIS];
  45       z[Y_AXIS] = z1[X_AXIS] * z2[Y_AXIS] + z1[Y_AXIS] * z2[X_AXIS];
  46   }
  47   return z;
  48 }
  49
  50
  51 Offset
  52 complex_conjugate (Offset o)
  53 {
  54   o[Y_AXIS] = - o[Y_AXIS];
  55   return o;
  56 }
  57
  58 Offset
  59 complex_divide (Offset z1, Offset z2)
  60 {
  61   z2 = complex_conjugate (z2);
  62   Offset z = complex_multiply (z1, z2);
  63   z *= 1/z2.length ();
  64   return z;
  65 }
  66
  67
  68
  69 Offset
  70 complex_exp (Offset o)
  71 {
  72   Real s = sin (o[Y_AXIS]);
  73   Real c = cos (o[Y_AXIS]);
  74
  75   Real r = exp (o[X_AXIS]);
  76
  77   return Offset(r*c, r*s);
  78 }
  79
  80 Real
  81 Offset::arg () const
  82 {
  83   return atan2 (coordinate_a_[Y_AXIS], coordinate_a_[X_AXIS]);
  84 }
  85
  86 /**
  87    euclidian vector length / complex modulus
  88  */
  89 Real
  90 Offset::length () const
  91 {
  92   return sqrt (sqr (coordinate_a_[X_AXIS]) + sqr (coordinate_a_[Y_AXIS]));
  93 }
  94 void
  95 Offset::mirror (Axis a)
  96 {
  97   coordinate_a_[a] = - coordinate_a_[a];
  98 }