1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
|
/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "AK/ByteBuffer.h"
#include <AK/Checked.h>
#include <AK/LogStream.h>
#include <AK/Utf32View.h>
#include <AK/Utf8View.h>
#include <LibCore/File.h>
#include <LibTTF/Cmap.h>
#include <LibTTF/Font.h>
#include <LibTTF/Glyf.h>
#include <LibTTF/Tables.h>
#include <LibTextCodec/Decoder.h>
#include <math.h>
namespace TTF {
u16 be_u16(const u8* ptr);
u32 be_u32(const u8* ptr);
i16 be_i16(const u8* ptr);
float be_fword(const u8* ptr);
u32 tag_from_str(const char* str);
u16 be_u16(const u8* ptr)
{
return (((u16)ptr[0]) << 8) | ((u16)ptr[1]);
}
u32 be_u32(const u8* ptr)
{
return (((u32)ptr[0]) << 24) | (((u32)ptr[1]) << 16) | (((u32)ptr[2]) << 8) | ((u32)ptr[3]);
}
i16 be_i16(const u8* ptr)
{
return (((i16)ptr[0]) << 8) | ((i16)ptr[1]);
}
float be_fword(const u8* ptr)
{
return (float)be_i16(ptr) / (float)(1 << 14);
}
u32 tag_from_str(const char* str)
{
return be_u32((const u8*)str);
}
Optional<Head> Head::from_slice(const ReadonlyBytes& slice)
{
if (slice.size() < (size_t)Sizes::Table) {
return {};
}
return Head(slice);
}
u16 Head::units_per_em() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::UnitsPerEM));
}
i16 Head::xmin() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::XMin));
}
i16 Head::ymin() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::YMin));
}
i16 Head::xmax() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::XMax));
}
i16 Head::ymax() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::YMax));
}
u16 Head::lowest_recommended_ppem() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::LowestRecPPEM));
}
IndexToLocFormat Head::index_to_loc_format() const
{
i16 raw = be_i16(m_slice.offset_pointer((u32)Offsets::IndexToLocFormat));
switch (raw) {
case 0:
return IndexToLocFormat::Offset16;
case 1:
return IndexToLocFormat::Offset32;
default:
ASSERT_NOT_REACHED();
}
}
Optional<Hhea> Hhea::from_slice(const ReadonlyBytes& slice)
{
if (slice.size() < (size_t)Sizes::Table) {
return {};
}
return Hhea(slice);
}
i16 Hhea::ascender() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::Ascender));
}
i16 Hhea::descender() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::Descender));
}
i16 Hhea::line_gap() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::LineGap));
}
u16 Hhea::advance_width_max() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::AdvanceWidthMax));
}
u16 Hhea::number_of_h_metrics() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::NumberOfHMetrics));
}
Optional<Maxp> Maxp::from_slice(const ReadonlyBytes& slice)
{
if (slice.size() < (size_t)Sizes::TableV0p5) {
return {};
}
return Maxp(slice);
}
u16 Maxp::num_glyphs() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::NumGlyphs));
}
Optional<Hmtx> Hmtx::from_slice(const ReadonlyBytes& slice, u32 num_glyphs, u32 number_of_h_metrics)
{
if (slice.size() < number_of_h_metrics * (u32)Sizes::LongHorMetric + (num_glyphs - number_of_h_metrics) * (u32)Sizes::LeftSideBearing) {
return {};
}
return Hmtx(slice, num_glyphs, number_of_h_metrics);
}
Optional<Name> Name::from_slice(const ReadonlyBytes& slice)
{
return Name(slice);
}
String Name::string_for_id(NameId id) const
{
auto num_entries = be_u16(m_slice.offset_pointer(2));
auto string_offset = be_u16(m_slice.offset_pointer(4));
for (int i = 0; i < num_entries; ++i) {
auto this_id = be_u16(m_slice.offset_pointer(6 + i * 12 + 6));
if (this_id != (u16)id)
continue;
auto platform = be_u16(m_slice.offset_pointer(6 + i * 12 + 0));
auto length = be_u16(m_slice.offset_pointer(6 + i * 12 + 8));
auto offset = be_u16(m_slice.offset_pointer(6 + i * 12 + 10));
if (platform == (u16)Platform::Windows) {
static auto& decoder = *TextCodec::decoder_for("utf-16be");
return decoder.to_utf8(StringView { (const char*)m_slice.offset_pointer(string_offset + offset), length });
}
return String((const char*)m_slice.offset_pointer(string_offset + offset), length);
}
return String::empty();
}
GlyphHorizontalMetrics Hmtx::get_glyph_horizontal_metrics(u32 glyph_id) const
{
ASSERT(glyph_id < m_num_glyphs);
if (glyph_id < m_number_of_h_metrics) {
auto offset = glyph_id * (u32)Sizes::LongHorMetric;
u16 advance_width = be_u16(m_slice.offset_pointer(offset));
i16 left_side_bearing = be_i16(m_slice.offset_pointer(offset + 2));
return GlyphHorizontalMetrics {
.advance_width = advance_width,
.left_side_bearing = left_side_bearing,
};
}
auto offset = m_number_of_h_metrics * (u32)Sizes::LongHorMetric + (glyph_id - m_number_of_h_metrics) * (u32)Sizes::LeftSideBearing;
u16 advance_width = be_u16(m_slice.offset_pointer((m_number_of_h_metrics - 1) * (u32)Sizes::LongHorMetric));
i16 left_side_bearing = be_i16(m_slice.offset_pointer(offset));
return GlyphHorizontalMetrics {
.advance_width = advance_width,
.left_side_bearing = left_side_bearing,
};
}
RefPtr<Font> Font::load_from_file(const StringView& path, unsigned index)
{
auto file_or_error = Core::File::open(String(path), Core::IODevice::ReadOnly);
if (file_or_error.is_error()) {
dbgln("Could not open file: {}", file_or_error.error());
return nullptr;
}
auto file = file_or_error.value();
if (!file->open(Core::IODevice::ReadOnly)) {
dbgln("Could not open file");
return nullptr;
}
auto buffer = file->read_all();
return load_from_memory(buffer, index);
}
RefPtr<Font> Font::load_from_memory(ByteBuffer& buffer, unsigned index)
{
if (buffer.size() < 4) {
dbgln("Font file too small");
return nullptr;
}
u32 tag = be_u32(buffer.data());
if (tag == tag_from_str("ttcf")) {
// It's a font collection
if (buffer.size() < (u32)Sizes::TTCHeaderV1 + sizeof(u32) * (index + 1)) {
dbgln("Font file too small");
return nullptr;
}
u32 offset = be_u32(buffer.offset_pointer((u32)Sizes::TTCHeaderV1 + sizeof(u32) * index));
return load_from_offset(move(buffer), offset);
}
if (tag == tag_from_str("OTTO")) {
dbgln("CFF fonts not supported yet");
return nullptr;
}
if (tag != 0x00010000) {
dbgln("Not a valid font");
return nullptr;
}
return load_from_offset(move(buffer), 0);
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
RefPtr<Font> Font::load_from_offset(ByteBuffer&& buffer, u32 offset)
{
if (Checked<u32>::addition_would_overflow(offset, (u32)Sizes::OffsetTable)) {
dbgln("Invalid offset in font header");
return nullptr;
}
if (buffer.size() < offset + (u32)Sizes::OffsetTable) {
dbgln("Font file too small");
return nullptr;
}
Optional<ReadonlyBytes> opt_head_slice = {};
Optional<ReadonlyBytes> opt_name_slice = {};
Optional<ReadonlyBytes> opt_hhea_slice = {};
Optional<ReadonlyBytes> opt_maxp_slice = {};
Optional<ReadonlyBytes> opt_hmtx_slice = {};
Optional<ReadonlyBytes> opt_cmap_slice = {};
Optional<ReadonlyBytes> opt_loca_slice = {};
Optional<ReadonlyBytes> opt_glyf_slice = {};
Optional<Head> opt_head = {};
Optional<Name> opt_name = {};
Optional<Hhea> opt_hhea = {};
Optional<Maxp> opt_maxp = {};
Optional<Hmtx> opt_hmtx = {};
Optional<Cmap> opt_cmap = {};
Optional<Loca> opt_loca = {};
auto num_tables = be_u16(buffer.offset_pointer(offset + (u32)Offsets::NumTables));
if (buffer.size() < offset + (u32)Sizes::OffsetTable + num_tables * (u32)Sizes::TableRecord) {
dbgln("Font file too small");
return nullptr;
}
for (auto i = 0; i < num_tables; i++) {
u32 record_offset = offset + (u32)Sizes::OffsetTable + i * (u32)Sizes::TableRecord;
u32 tag = be_u32(buffer.offset_pointer(record_offset));
u32 table_offset = be_u32(buffer.offset_pointer(record_offset + (u32)Offsets::TableRecord_Offset));
u32 table_length = be_u32(buffer.offset_pointer(record_offset + (u32)Offsets::TableRecord_Length));
if (Checked<u32>::addition_would_overflow(table_offset, table_length)) {
dbgln("Invalid table offset/length in font.");
return nullptr;
}
if (buffer.size() < table_offset + table_length) {
dbgln("Font file too small");
return nullptr;
}
auto buffer_here = ReadonlyBytes(buffer.offset_pointer(table_offset), table_length);
// Get the table offsets we need.
if (tag == tag_from_str("head")) {
opt_head_slice = buffer_here;
} else if (tag == tag_from_str("name")) {
opt_name_slice = buffer_here;
} else if (tag == tag_from_str("hhea")) {
opt_hhea_slice = buffer_here;
} else if (tag == tag_from_str("maxp")) {
opt_maxp_slice = buffer_here;
} else if (tag == tag_from_str("hmtx")) {
opt_hmtx_slice = buffer_here;
} else if (tag == tag_from_str("cmap")) {
opt_cmap_slice = buffer_here;
} else if (tag == tag_from_str("loca")) {
opt_loca_slice = buffer_here;
} else if (tag == tag_from_str("glyf")) {
opt_glyf_slice = buffer_here;
}
}
if (!opt_head_slice.has_value() || !(opt_head = Head::from_slice(opt_head_slice.value())).has_value()) {
dbgln("Could not load Head");
return nullptr;
}
auto head = opt_head.value();
if (!opt_name_slice.has_value() || !(opt_name = Name::from_slice(opt_name_slice.value())).has_value()) {
dbgln("Could not load Name");
return nullptr;
}
auto name = opt_name.value();
if (!opt_hhea_slice.has_value() || !(opt_hhea = Hhea::from_slice(opt_hhea_slice.value())).has_value()) {
dbgln("Could not load Hhea");
return nullptr;
}
auto hhea = opt_hhea.value();
if (!opt_maxp_slice.has_value() || !(opt_maxp = Maxp::from_slice(opt_maxp_slice.value())).has_value()) {
dbgln("Could not load Maxp");
return nullptr;
}
auto maxp = opt_maxp.value();
if (!opt_hmtx_slice.has_value() || !(opt_hmtx = Hmtx::from_slice(opt_hmtx_slice.value(), maxp.num_glyphs(), hhea.number_of_h_metrics())).has_value()) {
dbgln("Could not load Hmtx");
return nullptr;
}
auto hmtx = opt_hmtx.value();
if (!opt_cmap_slice.has_value() || !(opt_cmap = Cmap::from_slice(opt_cmap_slice.value())).has_value()) {
dbgln("Could not load Cmap");
return nullptr;
}
auto cmap = opt_cmap.value();
if (!opt_loca_slice.has_value() || !(opt_loca = Loca::from_slice(opt_loca_slice.value(), maxp.num_glyphs(), head.index_to_loc_format())).has_value()) {
dbgln("Could not load Loca");
return nullptr;
}
auto loca = opt_loca.value();
if (!opt_glyf_slice.has_value()) {
dbgln("Could not load Glyf");
return nullptr;
}
auto glyf = Glyf(opt_glyf_slice.value());
// Select cmap table. FIXME: Do this better. Right now, just looks for platform "Windows"
// and corresponding encoding "Unicode full repertoire", or failing that, "Unicode BMP"
for (u32 i = 0; i < cmap.num_subtables(); i++) {
auto opt_subtable = cmap.subtable(i);
if (!opt_subtable.has_value()) {
continue;
}
auto subtable = opt_subtable.value();
if (subtable.platform_id() == Cmap::Subtable::Platform::Windows) {
if (subtable.encoding_id() == (u16)Cmap::Subtable::WindowsEncoding::UnicodeFullRepertoire) {
cmap.set_active_index(i);
break;
}
if (subtable.encoding_id() == (u16)Cmap::Subtable::WindowsEncoding::UnicodeBMP) {
cmap.set_active_index(i);
break;
}
}
}
return adopt(*new Font(move(buffer), move(head), move(name), move(hhea), move(maxp), move(hmtx), move(cmap), move(loca), move(glyf)));
}
ScaledFontMetrics Font::metrics(float x_scale, float y_scale) const
{
auto ascender = m_hhea.ascender() * y_scale;
auto descender = m_hhea.descender() * y_scale;
auto line_gap = m_hhea.line_gap() * y_scale;
auto advance_width_max = m_hhea.advance_width_max() * x_scale;
return ScaledFontMetrics {
.ascender = (int)roundf(ascender),
.descender = (int)roundf(descender),
.line_gap = (int)roundf(line_gap),
.advance_width_max = (int)roundf(advance_width_max),
};
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
ScaledGlyphMetrics Font::glyph_metrics(u32 glyph_id, float x_scale, float y_scale) const
{
if (glyph_id >= glyph_count()) {
glyph_id = 0;
}
auto horizontal_metrics = m_hmtx.get_glyph_horizontal_metrics(glyph_id);
auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
auto glyph = m_glyf.glyph(glyph_offset);
int ascender = glyph.ascender();
int descender = glyph.descender();
return ScaledGlyphMetrics {
.ascender = (int)roundf(ascender * y_scale),
.descender = (int)roundf(descender * y_scale),
.advance_width = (int)roundf(horizontal_metrics.advance_width * x_scale),
.left_side_bearing = (int)roundf(horizontal_metrics.left_side_bearing * x_scale),
};
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
RefPtr<Gfx::Bitmap> Font::raster_glyph(u32 glyph_id, float x_scale, float y_scale) const
{
if (glyph_id >= glyph_count()) {
glyph_id = 0;
}
auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
auto glyph = m_glyf.glyph(glyph_offset);
return glyph.raster(x_scale, y_scale, [&](u16 glyph_id) {
if (glyph_id >= glyph_count()) {
glyph_id = 0;
}
auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
return m_glyf.glyph(glyph_offset);
});
}
u32 Font::glyph_count() const
{
return m_maxp.num_glyphs();
}
u16 Font::units_per_em() const
{
return m_head.units_per_em();
}
String Font::family() const
{
auto string = m_name.typographic_family_name();
if (!string.is_empty())
return string;
return m_name.family_name();
}
String Font::variant() const
{
auto string = m_name.typographic_subfamily_name();
if (!string.is_empty())
return string;
return m_name.subfamily_name();
}
u16 Font::weight() const
{
// FIXME: This is pretty naive, read weight from the actual font table(s)
auto variant_name = variant();
if (variant_name == "Thin")
return 100;
if (variant_name == "Extra Light")
return 200;
if (variant_name == "Light")
return 300;
if (variant_name == "Regular")
return 400;
if (variant_name == "Medium")
return 500;
if (variant_name == "Semi Bold")
return 600;
if (variant_name == "Bold")
return 700;
if (variant_name == "Extra Bold")
return 800;
if (variant_name == "Black")
return 900;
if (variant_name == "Extra Black")
return 950;
return 400;
}
bool Font::is_fixed_width() const
{
// FIXME: Read this information from the font file itself.
// FIXME: Although, it appears some application do similar hacks
return glyph_metrics(glyph_id_for_codepoint('.'), 1, 1).advance_width == glyph_metrics(glyph_id_for_codepoint('X'), 1, 1).advance_width;
}
int ScaledFont::width(const StringView& string) const
{
Utf8View utf8 { string };
return width(utf8);
}
int ScaledFont::width(const Utf8View& utf8) const
{
int width = 0;
for (u32 codepoint : utf8) {
u32 glyph_id = glyph_id_for_codepoint(codepoint);
auto metrics = glyph_metrics(glyph_id);
width += metrics.advance_width;
}
return width;
}
int ScaledFont::width(const Utf32View& utf32) const
{
int width = 0;
for (size_t i = 0; i < utf32.length(); i++) {
u32 glyph_id = glyph_id_for_codepoint(utf32.code_points()[i]);
auto metrics = glyph_metrics(glyph_id);
width += metrics.advance_width;
}
return width;
}
RefPtr<Gfx::Bitmap> ScaledFont::raster_glyph(u32 glyph_id) const
{
auto glyph_iterator = m_cached_glyph_bitmaps.find(glyph_id);
if (glyph_iterator != m_cached_glyph_bitmaps.end())
return glyph_iterator->value;
auto glyph_bitmap = m_font->raster_glyph(glyph_id, m_x_scale, m_y_scale);
m_cached_glyph_bitmaps.set(glyph_id, glyph_bitmap);
return glyph_bitmap;
}
Gfx::Glyph ScaledFont::glyph(u32 code_point) const
{
auto id = glyph_id_for_codepoint(code_point);
auto bitmap = raster_glyph(id);
auto metrics = glyph_metrics(id);
return Gfx::Glyph(bitmap, metrics.left_side_bearing, metrics.advance_width, metrics.ascender);
}
u8 ScaledFont::glyph_width(size_t code_point) const
{
auto id = glyph_id_for_codepoint(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
int ScaledFont::glyph_or_emoji_width(u32 code_point) const
{
auto id = glyph_id_for_codepoint(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
u8 ScaledFont::glyph_fixed_width() const
{
return glyph_metrics(glyph_id_for_codepoint(' ')).advance_width;
}
}
|
