flower/include/drul-array.hh

   1 /*
   2   drul-array.hh -- declare Drul_array
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #ifndef DRUL_ARRAY_HH
  10 #define DRUL_ARRAY_HH
  11
  12 #include "direction.hh"
  13 #include "real.hh"
  14
  15 /**
  16    Left/right or Up/down arrays. Drul is nicer sounding than udlr
  17 */
  18 template<class T>
  19 struct Drul_array
  20 {
  21   T array_[2];
  22   T &at (Direction d)
  23   {
  24     assert (d == 1 || d == -1);
  25     return array_[ (d + 1) / 2];
  26   }
  27   T const &at (Direction d) const
  28   {
  29     assert (d == 1 || d == -1);
  30     return array_[ (d + 1) / 2];
  31   }
  32   T &operator [] (Direction d)
  33   {
  34     return at (d);
  35   }
  36   T const& operator [] (Direction d) const
  37   {
  38     return at (d);
  39   }
  40   Drul_array ()
  41   {
  42   }
  43   Drul_array (T const &t1, T const &t2)
  44   {
  45     set (t1, t2);
  46   }
  47   void set (T const &t1, T const &t2)
  48   {
  49     array_[0] = t1;
  50     array_[1] = t2;
  51   }
  52 };
  53
  54 template<class T>
  55 void
  56 scale_drul (Drul_array<T> *dr, T x)
  57 {
  58   dr->at (LEFT) *= x;
  59   dr->at (RIGHT) *= x;
  60 }
  61
  62 inline Real
  63 linear_combination (Drul_array<Real> const &d, Real x)
  64 {
  65   return ((1.0 - x) * Real (d.at (LEFT))
  66           + (x + 1.0) * Real (d.at (RIGHT))) * 0.5;
  67 }
  68
  69 #endif /* DRUL_ARRAY_HH */