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
|
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "head.h"
#include <cstring>
// head - Font Header
// http://www.microsoft.com/typography/otspec/head.htm
#define TABLE_NAME "head"
namespace ots {
bool ots_head_parse(Font* font, const uint8_t *data, size_t length) {
Buffer table(data, length);
OpenTypeHEAD *head = new OpenTypeHEAD;
font->head = head;
uint32_t version = 0;
if (!table.ReadU32(&version) ||
!table.ReadU32(&head->revision)) {
return OTS_FAILURE_MSG("Failed to read head header");
}
if (version >> 16 != 1) {
return OTS_FAILURE_MSG("Bad head table version of %d", version);
}
// Skip the checksum adjustment
if (!table.Skip(4)) {
return OTS_FAILURE_MSG("Failed to read checksum");
}
uint32_t magic;
if (!table.ReadU32(&magic) || magic != 0x5F0F3CF5) {
return OTS_FAILURE_MSG("Failed to read font magic number");
}
if (!table.ReadU16(&head->flags)) {
return OTS_FAILURE_MSG("Failed to read head flags");
}
// We allow bits 0..4, 11..13
head->flags &= 0x381f;
if (!table.ReadU16(&head->ppem)) {
return OTS_FAILURE_MSG("Failed to read pixels per em");
}
// ppem must be in range
if (head->ppem < 16 ||
head->ppem > 16384) {
return OTS_FAILURE_MSG("Bad ppm of %d", head->ppem);
}
// ppem must be a power of two
#if 0
// We don't call ots_failure() for now since lots of TrueType fonts are
// not following this rule. Putting OTS_WARNING here is too noisy.
if ((head->ppem - 1) & head->ppem) {
return OTS_FAILURE_MSG("ppm not a power of two: %d", head->ppem);
}
#endif
if (!table.ReadR64(&head->created) ||
!table.ReadR64(&head->modified)) {
return OTS_FAILURE_MSG("Can't read font dates");
}
if (!table.ReadS16(&head->xmin) ||
!table.ReadS16(&head->ymin) ||
!table.ReadS16(&head->xmax) ||
!table.ReadS16(&head->ymax)) {
return OTS_FAILURE_MSG("Failed to read font bounding box");
}
if (head->xmin > head->xmax) {
return OTS_FAILURE_MSG("Bad x dimension in the font bounding box (%d, %d)", head->xmin, head->xmax);
}
if (head->ymin > head->ymax) {
return OTS_FAILURE_MSG("Bad y dimension in the font bounding box (%d, %d)", head->ymin, head->ymax);
}
if (!table.ReadU16(&head->mac_style)) {
return OTS_FAILURE_MSG("Failed to read font style");
}
// We allow bits 0..6
head->mac_style &= 0x7f;
if (!table.ReadU16(&head->min_ppem)) {
return OTS_FAILURE_MSG("Failed to read font minimum ppm");
}
// We don't care about the font direction hint
if (!table.Skip(2)) {
return OTS_FAILURE_MSG("Failed to skip font direction hint");
}
if (!table.ReadS16(&head->index_to_loc_format)) {
return OTS_FAILURE_MSG("Failed to read index to loc format");
}
if (head->index_to_loc_format < 0 ||
head->index_to_loc_format > 1) {
return OTS_FAILURE_MSG("Bad index to loc format %d", head->index_to_loc_format);
}
int16_t glyph_data_format;
if (!table.ReadS16(&glyph_data_format) ||
glyph_data_format) {
return OTS_FAILURE_MSG("Failed to read glyph data format");
}
return true;
}
bool ots_head_should_serialise(Font *font) {
return font->head != NULL;
}
bool ots_head_serialise(OTSStream *out, Font *font) {
const OpenTypeHEAD *head = font->head;
if (!out->WriteU32(0x00010000) ||
!out->WriteU32(head->revision) ||
!out->WriteU32(0) || // check sum not filled in yet
!out->WriteU32(0x5F0F3CF5) ||
!out->WriteU16(head->flags) ||
!out->WriteU16(head->ppem) ||
!out->WriteR64(head->created) ||
!out->WriteR64(head->modified) ||
!out->WriteS16(head->xmin) ||
!out->WriteS16(head->ymin) ||
!out->WriteS16(head->xmax) ||
!out->WriteS16(head->ymax) ||
!out->WriteU16(head->mac_style) ||
!out->WriteU16(head->min_ppem) ||
!out->WriteS16(2) ||
!out->WriteS16(head->index_to_loc_format) ||
!out->WriteS16(0)) {
return OTS_FAILURE_MSG("Failed to write head table");
}
return true;
}
void ots_head_reuse(Font *font, Font *other) {
font->head = other->head;
font->head_reused = true;
}
void ots_head_free(Font *font) {
delete font->head;
}
} // namespace
#undef TABLE_NAME
|
