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
|
#include <mbgl/text/glyph_pbf.hpp>
#include <mbgl/text/glyph_atlas.hpp>
#include <mbgl/text/glyph_atlas_observer.hpp>
#include <mbgl/text/glyph_set.hpp>
#include <mbgl/storage/file_source.hpp>
#include <mbgl/storage/resource.hpp>
#include <mbgl/storage/response.hpp>
#include <mbgl/util/exception.hpp>
#include <mbgl/util/string.hpp>
#include <mbgl/util/token.hpp>
#include <mbgl/util/url.hpp>
#include <protozero/pbf_reader.hpp>
namespace mbgl {
namespace {
void parseGlyphPBF(GlyphSet& glyphSet, const GlyphRange& glyphRange, const std::string& data) {
protozero::pbf_reader glyphs_pbf(data);
while (glyphs_pbf.next(1)) {
auto fontstack_pbf = glyphs_pbf.get_message();
while (fontstack_pbf.next(3)) {
auto glyph_pbf = fontstack_pbf.get_message();
SDFGlyph glyph;
bool hasID = false, hasWidth = false, hasHeight = false, hasLeft = false,
hasTop = false, hasAdvance = false;
while (glyph_pbf.next()) {
switch (glyph_pbf.tag()) {
case 1: // id
glyph.id = glyph_pbf.get_uint32();
hasID = true;
break;
case 2: // bitmap
glyph.bitmap = glyph_pbf.get_string();
break;
case 3: // width
glyph.metrics.width = glyph_pbf.get_uint32();
hasWidth = true;
break;
case 4: // height
glyph.metrics.height = glyph_pbf.get_uint32();
hasHeight = true;
break;
case 5: // left
glyph.metrics.left = glyph_pbf.get_sint32();
hasLeft = true;
break;
case 6: // top
glyph.metrics.top = glyph_pbf.get_sint32();
hasTop = true;
break;
case 7: // advance
glyph.metrics.advance = glyph_pbf.get_uint32();
hasAdvance = true;
break;
default:
glyph_pbf.skip();
break;
}
}
// If the area of width/height is non-zero, we need to adjust the expected size
// with the implicit border size, otherwise we expect there to be no bitmap at all.
const uint32_t expectedBitmapSize =
glyph.metrics.width && glyph.metrics.height
? (glyph.metrics.width + 2 * SDFGlyph::borderSize) *
(glyph.metrics.height + 2 * SDFGlyph::borderSize)
: 0;
// Only treat this glyph as a correct glyph if it has all required fields, and if
// the bitmap has the correct length. It also needs to satisfy a few metrics conditions
// that ensure that the glyph isn't bogus. All other glyphs are malformed.
// We're also discarding all glyphs that are outside the expected glyph range.
if (hasID && hasWidth && hasHeight && hasLeft && hasTop && hasAdvance &&
glyph.metrics.width < 256 && glyph.metrics.height < 256 &&
glyph.metrics.left >= -128 && glyph.metrics.left < 128 &&
glyph.metrics.top >= -128 && glyph.metrics.top < 128 &&
glyph.metrics.advance < 256 && glyph.bitmap.size() == expectedBitmapSize &&
glyph.id >= glyphRange.first && glyph.id <= glyphRange.second) {
glyphSet.insert(glyph.id, std::move(glyph));
}
}
}
}
} // namespace
GlyphPBF::GlyphPBF(GlyphAtlas* atlas,
const FontStack& fontStack,
const GlyphRange& glyphRange,
GlyphAtlasObserver* observer_,
FileSource& fileSource)
: parsed(false),
observer(observer_) {
req = fileSource.request(Resource::glyphs(atlas->getURL(), fontStack, glyphRange), [this, atlas, fontStack, glyphRange](Response res) {
if (res.error) {
observer->onGlyphsError(fontStack, glyphRange, std::make_exception_ptr(std::runtime_error(res.error->message)));
} else if (res.notModified) {
return;
} else if (res.noContent) {
parsed = true;
observer->onGlyphsLoaded(fontStack, glyphRange);
} else {
try {
parseGlyphPBF(**atlas->getGlyphSet(fontStack), glyphRange, *res.data);
} catch (...) {
observer->onGlyphsError(fontStack, glyphRange, std::current_exception());
return;
}
parsed = true;
observer->onGlyphsLoaded(fontStack, glyphRange);
}
});
}
GlyphPBF::~GlyphPBF() = default;
} // namespace mbgl
|
