1 | /* |
2 | * Copyright © 2017 Google, Inc. |
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 | * Google Author(s): Behdad Esfahbod |
25 | */ |
26 | |
27 | #ifndef HB_OT_VAR_AVAR_TABLE_HH |
28 | #define HB_OT_VAR_AVAR_TABLE_HH |
29 | |
30 | #include "hb-open-type-private.hh" |
31 | |
32 | namespace OT { |
33 | |
34 | |
35 | struct AxisValueMap |
36 | { |
37 | inline bool sanitize (hb_sanitize_context_t *c) const |
38 | { |
39 | TRACE_SANITIZE (this); |
40 | return_trace (c->check_struct (this)); |
41 | } |
42 | |
43 | public: |
44 | F2DOT14 fromCoord; /* A normalized coordinate value obtained using |
45 | * default normalization. */ |
46 | F2DOT14 toCoord; /* The modified, normalized coordinate value. */ |
47 | |
48 | public: |
49 | DEFINE_SIZE_STATIC (4); |
50 | }; |
51 | |
52 | struct SegmentMaps : ArrayOf<AxisValueMap> |
53 | { |
54 | inline int map (int value) const |
55 | { |
56 | /* The following special-cases are not part of OpenType, which requires |
57 | * that at least -1, 0, and +1 must be mapped. But we include these as |
58 | * part of a better error recovery scheme. */ |
59 | |
60 | if (len < 2) |
61 | { |
62 | if (!len) |
63 | return value; |
64 | else /* len == 1*/ |
65 | return value - array[0].fromCoord + array[0].toCoord; |
66 | } |
67 | |
68 | if (value <= array[0].fromCoord) |
69 | return value - array[0].fromCoord + array[0].toCoord; |
70 | |
71 | unsigned int i; |
72 | unsigned int count = len; |
73 | for (i = 1; i < count && value > array[i].fromCoord; i++) |
74 | ; |
75 | |
76 | if (value >= array[i].fromCoord) |
77 | return value - array[i].fromCoord + array[i].toCoord; |
78 | |
79 | if (unlikely (array[i-1].fromCoord == array[i].fromCoord)) |
80 | return array[i-1].toCoord; |
81 | |
82 | int denom = array[i].fromCoord - array[i-1].fromCoord; |
83 | return array[i-1].toCoord + |
84 | ((array[i].toCoord - array[i-1].toCoord) * |
85 | (value - array[i-1].fromCoord) + denom/2) / denom; |
86 | } |
87 | |
88 | DEFINE_SIZE_ARRAY (2, array); |
89 | }; |
90 | |
91 | /* |
92 | * avar — Axis Variations Table |
93 | */ |
94 | |
95 | #define HB_OT_TAG_avar HB_TAG('a','v','a','r') |
96 | |
97 | struct avar |
98 | { |
99 | static const hb_tag_t tableTag = HB_OT_TAG_avar; |
100 | |
101 | inline bool sanitize (hb_sanitize_context_t *c) const |
102 | { |
103 | TRACE_SANITIZE (this); |
104 | if (unlikely (!(version.sanitize (c) && |
105 | version.major == 1 && |
106 | c->check_struct (this)))) |
107 | return_trace (false); |
108 | |
109 | const SegmentMaps *map = &axisSegmentMapsZ; |
110 | unsigned int count = axisCount; |
111 | for (unsigned int i = 0; i < count; i++) |
112 | { |
113 | if (unlikely (!map->sanitize (c))) |
114 | return_trace (false); |
115 | map = &StructAfter<SegmentMaps> (X: *map); |
116 | } |
117 | |
118 | return_trace (true); |
119 | } |
120 | |
121 | inline void map_coords (int *coords, unsigned int coords_length) const |
122 | { |
123 | unsigned int count = MIN<unsigned int> (a: coords_length, b: axisCount); |
124 | |
125 | const SegmentMaps *map = &axisSegmentMapsZ; |
126 | for (unsigned int i = 0; i < count; i++) |
127 | { |
128 | coords[i] = map->map (value: coords[i]); |
129 | map = &StructAfter<SegmentMaps> (X: *map); |
130 | } |
131 | } |
132 | |
133 | protected: |
134 | FixedVersion<>version; /* Version of the avar table |
135 | * initially set to 0x00010000u */ |
136 | UINT16 reserved; /* This field is permanently reserved. Set to 0. */ |
137 | UINT16 axisCount; /* The number of variation axes in the font. This |
138 | * must be the same number as axisCount in the |
139 | * 'fvar' table. */ |
140 | SegmentMaps axisSegmentMapsZ; |
141 | |
142 | public: |
143 | DEFINE_SIZE_MIN (8); |
144 | }; |
145 | |
146 | } /* namespace OT */ |
147 | |
148 | |
149 | #endif /* HB_OT_VAR_AVAR_TABLE_HH */ |
150 | |