1/*
2 * Copyright © 2023 Behdad Esfahbod
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 */
24
25#ifndef HB_SUBSET_INSTANCER_SOLVER_HH
26#define HB_SUBSET_INSTANCER_SOLVER_HH
27
28#include "hb.hh"
29
30/* pre-normalized distances */
31struct TripleDistances
32{
33 TripleDistances (): negative (1.f), positive (1.f) {}
34 TripleDistances (float neg_, float pos_): negative (neg_), positive (pos_) {}
35 TripleDistances (float min, float default_, float max)
36 {
37 negative = default_ - min;
38 positive = max - default_;
39 }
40
41 float negative;
42 float positive;
43};
44
45struct Triple {
46
47 Triple () :
48 minimum (0.f), middle (0.f), maximum (0.f) {}
49
50 Triple (float minimum_, float middle_, float maximum_) :
51 minimum (minimum_), middle (middle_), maximum (maximum_) {}
52
53 bool operator == (const Triple &o) const
54 {
55 return minimum == o.minimum &&
56 middle == o.middle &&
57 maximum == o.maximum;
58 }
59
60 bool operator != (const Triple o) const
61 { return !(*this == o); }
62
63 bool is_point () const
64 { return minimum == middle && middle == maximum; }
65
66 bool contains (float point) const
67 { return minimum <= point && point <= maximum; }
68
69 /* from hb_array_t hash ()*/
70 uint32_t hash () const
71 {
72 uint32_t current = /*cbf29ce4*/0x84222325;
73 current = current ^ hb_hash (minimum);
74 current = current * 16777619;
75
76 current = current ^ hb_hash (middle);
77 current = current * 16777619;
78
79 current = current ^ hb_hash (maximum);
80 current = current * 16777619;
81 return current;
82 }
83
84
85 float minimum;
86 float middle;
87 float maximum;
88};
89
90using result_item_t = hb_pair_t<float, Triple>;
91using result_t = hb_vector_t<result_item_t>;
92
93/* renormalize a normalized value v to the range of an axis,
94 * considering the prenormalized distances as well as the new axis limits.
95 * Ported from fonttools */
96HB_INTERNAL float renormalizeValue (float v, const Triple &triple,
97 const TripleDistances &triple_distances,
98 bool extrapolate = true);
99/* Given a tuple (lower,peak,upper) "tent" and new axis limits
100 * (axisMin,axisDefault,axisMax), solves how to represent the tent
101 * under the new axis configuration. All values are in normalized
102 * -1,0,+1 coordinate system. Tent values can be outside this range.
103 *
104 * Return value: a list of tuples. Each tuple is of the form
105 * (scalar,tent), where scalar is a multipler to multiply any
106 * delta-sets by, and tent is a new tent for that output delta-set.
107 * If tent value is Triple{}, that is a special deltaset that should
108 * be always-enabled (called "gain").
109 */
110HB_INTERNAL result_t rebase_tent (Triple tent, Triple axisLimit, TripleDistances axis_triple_distances);
111
112#endif /* HB_SUBSET_INSTANCER_SOLVER_HH */
113