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#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;
protozero::data_view glyphData;
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
glyphData = glyph_pbf.get_view();
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;
}
}
// Only treat this glyph as a correct glyph if it has all required fields. 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.id < glyphRange.first || glyph.id > glyphRange.second) {
continue;
}
// 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.
if (glyph.metrics.width && glyph.metrics.height) {
const Size size {
glyph.metrics.width + 2 * SDFGlyph::borderSize,
glyph.metrics.height + 2 * SDFGlyph::borderSize
};
if (size.area() != glyphData.size()) {
continue;
}
glyph.bitmap = AlphaImage(size, reinterpret_cast<const uint8_t*>(glyphData.data()), glyphData.size());
}
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
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