summaryrefslogtreecommitdiff
path: root/src/mbgl/text/glyph_pbf.cpp
blob: 0c0626c0de26433ba0e954dd8c114fc715874212 (plain)
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
#include <mbgl/text/glyph_pbf.hpp>

#include <mbgl/storage/file_source.hpp>
#include <mbgl/storage/resource.hpp>
#include <mbgl/storage/response.hpp>
#include <mbgl/text/font_stack.hpp>
#include <mbgl/text/glyph_store.hpp>
#include <mbgl/util/exception.hpp>
#include <mbgl/util/pbf.hpp>
#include <mbgl/util/string.hpp>
#include <mbgl/util/thread_context.hpp>
#include <mbgl/util/token.hpp>
#include <mbgl/util/url.hpp>

namespace {

void parseGlyphPBF(mbgl::FontStack& stack, const std::string& data) {
    mbgl::pbf glyphs_pbf(reinterpret_cast<const uint8_t *>(data.data()), data.size());

    while (glyphs_pbf.next()) {
        if (glyphs_pbf.tag == 1) { // stacks
            mbgl::pbf fontstack_pbf = glyphs_pbf.message();
            while (fontstack_pbf.next()) {
                if (fontstack_pbf.tag == 3) { // glyphs
                    mbgl::pbf glyph_pbf = fontstack_pbf.message();

                    mbgl::SDFGlyph glyph;

                    while (glyph_pbf.next()) {
                        if (glyph_pbf.tag == 1) { // id
                            glyph.id = glyph_pbf.varint();
                        } else if (glyph_pbf.tag == 2) { // bitmap
                            glyph.bitmap = glyph_pbf.string();
                        } else if (glyph_pbf.tag == 3) { // width
                            glyph.metrics.width = glyph_pbf.varint();
                        } else if (glyph_pbf.tag == 4) { // height
                            glyph.metrics.height = glyph_pbf.varint();
                        } else if (glyph_pbf.tag == 5) { // left
                            glyph.metrics.left = glyph_pbf.svarint();
                        } else if (glyph_pbf.tag == 6) { // top
                            glyph.metrics.top = glyph_pbf.svarint();
                        } else if (glyph_pbf.tag == 7) { // advance
                            glyph.metrics.advance = glyph_pbf.varint();
                        } else {
                            glyph_pbf.skip();
                        }
                    }

                    stack.insert(glyph.id, glyph);
                } else {
                    fontstack_pbf.skip();
                }
            }
        } else {
            glyphs_pbf.skip();
        }
    }
}

} // namespace

namespace mbgl {

GlyphPBF::GlyphPBF(GlyphStore* store,
                   const std::string& fontStack,
                   const GlyphRange& glyphRange,
                   GlyphStore::Observer* observer_)
    : parsed(false),
      observer(observer_) {
    // Load the glyph set URL
    std::string url = util::replaceTokens(store->getURL(), [&](const std::string &name) -> std::string {
        if (name == "fontstack") return util::percentEncode(fontStack);
        if (name == "range") return util::toString(glyphRange.first) + "-" + util::toString(glyphRange.second);
        return "";
    });

    auto requestCallback = [this, store, fontStack, glyphRange](Response res) {
        if (res.stale) {
            // Only handle fresh responses.
            return;
        }
        req = nullptr;

        if (res.error) {
            observer->onGlyphsError(fontStack, glyphRange, std::make_exception_ptr(std::runtime_error(res.error->message)));
        } else {
            data = res.data;
            parse(store, fontStack, glyphRange);
        }
    };

    FileSource* fs = util::ThreadContext::getFileSource();
    req = fs->request({ Resource::Kind::Glyphs, url }, requestCallback);
}

GlyphPBF::~GlyphPBF() = default;

void GlyphPBF::parse(GlyphStore* store, const std::string& fontStack, const GlyphRange& glyphRange) {
    assert(data);
    if (data->empty()) {
        // If there is no data, this means we either haven't
        // received any data.
        return;
    }

    try {
        parseGlyphPBF(**store->getFontStack(fontStack), *data);
    } catch (...) {
        observer->onGlyphsError(fontStack, glyphRange, std::current_exception());
        return;
    }

    parsed = true;
    observer->onGlyphsLoaded(fontStack, glyphRange);
}

} // namespace mbgl