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.hh"
31
32/*
33 * avar -- Axis Variations
34 * https://docs.microsoft.com/en-us/typography/opentype/spec/avar
35 */
36
37#define HB_OT_TAG_avar HB_TAG('a','v','a','r')
38
39
40namespace OT {
41
42
43struct AxisValueMap
44{
45 inline bool sanitize (hb_sanitize_context_t *c) const
46 {
47 TRACE_SANITIZE (this);
48 return_trace (c->check_struct (this));
49 }
50
51 public:
52 F2DOT14 fromCoord; /* A normalized coordinate value obtained using
53 * default normalization. */
54 F2DOT14 toCoord; /* The modified, normalized coordinate value. */
55
56 public:
57 DEFINE_SIZE_STATIC (4);
58};
59
60struct SegmentMaps : ArrayOf<AxisValueMap>
61{
62 inline int map (int value) const
63 {
64 /* The following special-cases are not part of OpenType, which requires
65 * that at least -1, 0, and +1 must be mapped. But we include these as
66 * part of a better error recovery scheme. */
67
68 if (len < 2)
69 {
70 if (!len)
71 return value;
72 else /* len == 1*/
73 return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
74 }
75
76 if (value <= arrayZ[0].fromCoord)
77 return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
78
79 unsigned int i;
80 unsigned int count = len;
81 for (i = 1; i < count && value > arrayZ[i].fromCoord; i++)
82 ;
83
84 if (value >= arrayZ[i].fromCoord)
85 return value - arrayZ[i].fromCoord + arrayZ[i].toCoord;
86
87 if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord))
88 return arrayZ[i-1].toCoord;
89
90 int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord;
91 return arrayZ[i-1].toCoord +
92 ((arrayZ[i].toCoord - arrayZ[i-1].toCoord) *
93 (value - arrayZ[i-1].fromCoord) + denom/2) / denom;
94 }
95
96 DEFINE_SIZE_ARRAY (2, arrayZ);
97};
98
99struct avar
100{
101 static const hb_tag_t tableTag = HB_OT_TAG_avar;
102
103 inline bool sanitize (hb_sanitize_context_t *c) const
104 {
105 TRACE_SANITIZE (this);
106 if (unlikely (!(version.sanitize (c) &&
107 version.major == 1 &&
108 c->check_struct (this))))
109 return_trace (false);
110
111 const SegmentMaps *map = axisSegmentMapsZ;
112 unsigned int count = axisCount;
113 for (unsigned int i = 0; i < count; i++)
114 {
115 if (unlikely (!map->sanitize (c)))
116 return_trace (false);
117 map = &StructAfter<SegmentMaps> (*map);
118 }
119
120 return_trace (true);
121 }
122
123 inline void map_coords (int *coords, unsigned int coords_length) const
124 {
125 unsigned int count = MIN<unsigned int> (coords_length, axisCount);
126
127 const SegmentMaps *map = axisSegmentMapsZ;
128 for (unsigned int i = 0; i < count; i++)
129 {
130 coords[i] = map->map (coords[i]);
131 map = &StructAfter<SegmentMaps> (*map);
132 }
133 }
134
135 protected:
136 FixedVersion<>version; /* Version of the avar table
137 * initially set to 0x00010000u */
138 HBUINT16 reserved; /* This field is permanently reserved. Set to 0. */
139 HBUINT16 axisCount; /* The number of variation axes in the font. This
140 * must be the same number as axisCount in the
141 * 'fvar' table. */
142 SegmentMaps axisSegmentMapsZ[VAR];
143
144 public:
145 DEFINE_SIZE_MIN (8);
146};
147
148} /* namespace OT */
149
150
151#endif /* HB_OT_VAR_AVAR_TABLE_HH */
152