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comparison mupdf-source/thirdparty/harfbuzz/src/hb-aat-layout-trak-table.hh @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * Copyright © 2018 Ebrahim Byagowi
3 * Copyright © 2018 Google, Inc.
4 *
5 * This is part of HarfBuzz, a text shaping library.
6 *
7 * Permission is hereby granted, without written agreement and without
8 * license or royalty fees, to use, copy, modify, and distribute this
9 * software and its documentation for any purpose, provided that the
10 * above copyright notice and the following two paragraphs appear in
11 * all copies of this software.
12 *
13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17 * DAMAGE.
18 *
19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24 *
25 * Google Author(s): Behdad Esfahbod
26 */
27
28 #ifndef HB_AAT_LAYOUT_TRAK_TABLE_HH
29 #define HB_AAT_LAYOUT_TRAK_TABLE_HH
30
31 #include "hb-aat-layout-common.hh"
32 #include "hb-ot-layout.hh"
33 #include "hb-open-type.hh"
34
35 /*
36 * trak -- Tracking
37 * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6trak.html
38 */
39 #define HB_AAT_TAG_trak HB_TAG('t','r','a','k')
40
41
42 namespace AAT {
43
44
45 struct TrackTableEntry
46 {
47 friend struct TrackData;
48
49 float get_track_value () const { return track.to_float (); }
50
51 int get_value (const void *base, unsigned int index,
52 unsigned int table_size) const
53 { return (base+valuesZ).as_array (table_size)[index]; }
54
55 public:
56 bool sanitize (hb_sanitize_context_t *c, const void *base,
57 unsigned int table_size) const
58 {
59 TRACE_SANITIZE (this);
60 return_trace (likely (c->check_struct (this) &&
61 (valuesZ.sanitize (c, base, table_size))));
62 }
63
64 protected:
65 F16DOT16 track; /* Track value for this record. */
66 NameID trackNameID; /* The 'name' table index for this track.
67 * (a short word or phrase like "loose"
68 * or "very tight") */
69 NNOffset16To<UnsizedArrayOf<FWORD>>
70 valuesZ; /* Offset from start of tracking table to
71 * per-size tracking values for this track. */
72
73 public:
74 DEFINE_SIZE_STATIC (8);
75 };
76
77 struct TrackData
78 {
79 float interpolate_at (unsigned int idx,
80 float target_size,
81 const TrackTableEntry &trackTableEntry,
82 const void *base) const
83 {
84 unsigned int sizes = nSizes;
85 hb_array_t<const F16DOT16> size_table ((base+sizeTable).arrayZ, sizes);
86
87 float s0 = size_table[idx].to_float ();
88 float s1 = size_table[idx + 1].to_float ();
89 float t = unlikely (s0 == s1) ? 0.f : (target_size - s0) / (s1 - s0);
90 return t * trackTableEntry.get_value (base, idx + 1, sizes) +
91 (1.f - t) * trackTableEntry.get_value (base, idx, sizes);
92 }
93
94 int get_tracking (const void *base, float ptem) const
95 {
96 /*
97 * Choose track.
98 */
99 const TrackTableEntry *trackTableEntry = nullptr;
100 unsigned int count = nTracks;
101 for (unsigned int i = 0; i < count; i++)
102 {
103 /* Note: Seems like the track entries are sorted by values. But the
104 * spec doesn't explicitly say that. It just mentions it in the example. */
105
106 /* For now we only seek for track entries with zero tracking value */
107
108 if (trackTable[i].get_track_value () == 0.f)
109 {
110 trackTableEntry = &trackTable[i];
111 break;
112 }
113 }
114 if (!trackTableEntry) return 0.;
115
116 /*
117 * Choose size.
118 */
119 unsigned int sizes = nSizes;
120 if (!sizes) return 0.;
121 if (sizes == 1) return trackTableEntry->get_value (base, 0, sizes);
122
123 hb_array_t<const F16DOT16> size_table ((base+sizeTable).arrayZ, sizes);
124 unsigned int size_index;
125 for (size_index = 0; size_index < sizes - 1; size_index++)
126 if (size_table[size_index].to_float () >= ptem)
127 break;
128
129 return roundf (interpolate_at (size_index ? size_index - 1 : 0, ptem,
130 *trackTableEntry, base));
131 }
132
133 bool sanitize (hb_sanitize_context_t *c, const void *base) const
134 {
135 TRACE_SANITIZE (this);
136 return_trace (likely (c->check_struct (this) &&
137 sizeTable.sanitize (c, base, nSizes) &&
138 trackTable.sanitize (c, nTracks, base, nSizes)));
139 }
140
141 protected:
142 HBUINT16 nTracks; /* Number of separate tracks included in this table. */
143 HBUINT16 nSizes; /* Number of point sizes included in this table. */
144 NNOffset32To<UnsizedArrayOf<F16DOT16>>
145 sizeTable; /* Offset from start of the tracking table to
146 * Array[nSizes] of size values.. */
147 UnsizedArrayOf<TrackTableEntry>
148 trackTable; /* Array[nTracks] of TrackTableEntry records. */
149
150 public:
151 DEFINE_SIZE_ARRAY (8, trackTable);
152 };
153
154 struct trak
155 {
156 static constexpr hb_tag_t tableTag = HB_AAT_TAG_trak;
157
158 bool has_data () const { return version.to_int (); }
159
160 bool apply (hb_aat_apply_context_t *c) const
161 {
162 TRACE_APPLY (this);
163
164 hb_mask_t trak_mask = c->plan->trak_mask;
165
166 const float ptem = c->font->ptem;
167 if (unlikely (ptem <= 0.f))
168 return_trace (false);
169
170 hb_buffer_t *buffer = c->buffer;
171 if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
172 {
173 const TrackData &trackData = this+horizData;
174 int tracking = trackData.get_tracking (this, ptem);
175 hb_position_t offset_to_add = c->font->em_scalef_x (tracking / 2);
176 hb_position_t advance_to_add = c->font->em_scalef_x (tracking);
177 foreach_grapheme (buffer, start, end)
178 {
179 if (!(buffer->info[start].mask & trak_mask)) continue;
180 buffer->pos[start].x_advance += advance_to_add;
181 buffer->pos[start].x_offset += offset_to_add;
182 }
183 }
184 else
185 {
186 const TrackData &trackData = this+vertData;
187 int tracking = trackData.get_tracking (this, ptem);
188 hb_position_t offset_to_add = c->font->em_scalef_y (tracking / 2);
189 hb_position_t advance_to_add = c->font->em_scalef_y (tracking);
190 foreach_grapheme (buffer, start, end)
191 {
192 if (!(buffer->info[start].mask & trak_mask)) continue;
193 buffer->pos[start].y_advance += advance_to_add;
194 buffer->pos[start].y_offset += offset_to_add;
195 }
196 }
197
198 return_trace (true);
199 }
200
201 bool sanitize (hb_sanitize_context_t *c) const
202 {
203 TRACE_SANITIZE (this);
204
205 return_trace (likely (c->check_struct (this) &&
206 version.major == 1 &&
207 horizData.sanitize (c, this, this) &&
208 vertData.sanitize (c, this, this)));
209 }
210
211 protected:
212 FixedVersion<>version; /* Version of the tracking table
213 * (0x00010000u for version 1.0). */
214 HBUINT16 format; /* Format of the tracking table (set to 0). */
215 Offset16To<TrackData>
216 horizData; /* Offset from start of tracking table to TrackData
217 * for horizontal text (or 0 if none). */
218 Offset16To<TrackData>
219 vertData; /* Offset from start of tracking table to TrackData
220 * for vertical text (or 0 if none). */
221 HBUINT16 reserved; /* Reserved. Set to 0. */
222
223 public:
224 DEFINE_SIZE_STATIC (12);
225 };
226
227 } /* namespace AAT */
228
229
230 #endif /* HB_AAT_LAYOUT_TRAK_TABLE_HH */