1 /*
2 This file is part of LilyPond, the GNU music typesetter.
3
4 Copyright (C) 1997--2020 Han-Wen Nienhuys <hanwen@xs4all.nl>
5
6 LilyPond is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
10
11 LilyPond is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #ifndef DRUL_ARRAY_HH
21 #define DRUL_ARRAY_HH
22
23 #include "direction.hh"
24 #include "real.hh"
25
26 /**
27 Left/right or Up/down arrays. Drul is nicer sounding than udlr
28 */
29 template<class T>
30 struct Drul_array
31 {
32 T array_[2];
atDrul_array33 T &at (Direction d)
34 {
35 assert (d == 1 || d == -1);
36 return array_[d > 0];
37 }
atDrul_array38 T const &at (Direction d) const
39 {
40 assert (d == 1 || d == -1);
41 return array_[d > 0];
42 }
operator []Drul_array43 T &operator [] (Direction d)
44 {
45 return at (d);
46 }
operator []Drul_array47 T const &operator [] (Direction d) const
48 {
49 return at (d);
50 }
Drul_arrayDrul_array51 Drul_array ()
52 {
53 }
Drul_arrayDrul_array54 Drul_array (T const &t1, T const &t2)
55 {
56 set (t1, t2);
57 }
setDrul_array58 void set (T const &t1, T const &t2)
59 {
60 array_[0] = t1;
61 array_[1] = t2;
62 }
deltaDrul_array63 T delta () const
64 {
65 return at (RIGHT) - at (LEFT);
66 }
67 Real linear_combination (Real x) const;
68 };
69
70 template<class T>
71 void
scale_drul(Drul_array<T> * dr,T x)72 scale_drul (Drul_array<T> *dr, T x)
73 {
74 dr->at (LEFT) *= x;
75 dr->at (RIGHT) *= x;
76 }
77
78 template <>
79 inline Real
linear_combination(Real x) const80 Drul_array<Real>::linear_combination (Real x) const
81 {
82 return ((1.0 - x) * at (LEFT)
83 + (x + 1.0) * at (RIGHT)) * 0.5;
84 }
85
86 #endif /* DRUL_ARRAY_HH */
87