LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-12-28 13:43:45 +03:00
Code Issues Packages Projects Releases Wiki Activity

LibPDF/CFF: Add code for fdselect parsing

Browse Source 
This is one of the two top dict entries we need for CID-keyed fonts.
We don't send any CID-keyed font data into the CFF parser yet,
so no behavior change.
This commit is contained in:
Nico Weber 2024-02-09 08:08:00 -05:00 committed by Jelle Raaijmakers
parent 6ebddab448
commit 7ab4e53b99
Notes: sideshowbarker 2024-07-16 18:06:41 +09:00 
Author: https://github.com/nico
Commit: https://github.com/SerenityOS/serenity/commit/7ab4e53b99
Pull-request: https://github.com/SerenityOS/serenity/pull/23136
2 changed files with 57 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
Userland/Libraries/LibPDF/Fonts/CFF.cpp
View File

@ -128,6 +128,7 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
Vector<ByteBuffer> local_subroutines;
float defaultWidthX = 0;
float nominalWidthX = 0;
int fdselect_offset = 0;
TRY(parse_index(reader, [&](ReadonlyBytes const& element_data) {
Reader element_reader { element_data };
return parse_dict<TopDictOperator>(element_reader, [&](TopDictOperator op, Vector<DictOperand> const& operands) -> PDFErrorOr<void> {
@ -229,13 +230,16 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
}));
break;
}
case TopDictOperator::FDSelect:
if (!operands.is_empty())
fdselect_offset = operands[0].get<int>();
break;
case TopDictOperator::CIDFontVersion:
case TopDictOperator::CIDFontRevision:
case TopDictOperator::CIDFontType:
case TopDictOperator::CIDCount:
case TopDictOperator::UIDBase:
case TopDictOperator::FDArray:
case TopDictOperator::FDSelect:
case TopDictOperator::FontName:
// Keys for CID-keyed fonts that we don't need, at least at the moment.
break;
@ -306,6 +310,12 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
}
}
// CFF spec, "19 FDSelect"
if (fdselect_offset != 0) {
auto fdselect = TRY(parse_fdselect(Reader { cff_bytes.slice(fdselect_offset) }, glyphs.size()));
dbgln_if(CFF_DEBUG, "CFF has {} FDSelect entries", fdselect.size());
}
// Adjust glyphs' widths as they are deltas from nominalWidthX
for (auto& glyph : glyphs) {
if (!glyph.has_width())
@ -807,6 +817,51 @@ PDFErrorOr<Vector<CFF::SID>> CFF::parse_charset(Reader&& reader, size_t glyph_co
return names;
}
PDFErrorOr<Vector<u8>> CFF::parse_fdselect(Reader&& reader, size_t glyph_count)
{
Vector<u8> fd_selector_array; // Maps GIDs to their FD index.
// CFF spec, "19 FDSelect"
auto format = TRY(reader.try_read<Card8>());
if (format == 0) {
// CFF spec, "Table 27 Format 0"
// "(This format is identical to charset format 0 except that the notdef glyph is included in this case.)"
dbgln_if(CFF_DEBUG, "CFF fdselect format 0");
fd_selector_array.ensure_capacity(glyph_count);
for (size_t i = 0; i < glyph_count; i++)
fd_selector_array.append(TRY(reader.try_read<Card8>()));
} else if (format == 3) {
// CFF spec, "Table 28 Format 3"
dbgln_if(CFF_DEBUG, "CFF fdselect format 3");
// The spec presents this as n "Card16 first; Card8 fd;" struct entries followed by a Char16 sentinel value.
// But the code is shorter if we treat it as a Char16 start value followed by n "Card8 fd; Card16 end;" struct entries.
Card16 n_ranges = TRY(reader.try_read<BigEndian<Card16>>());
Card16 begin = TRY(reader.try_read<BigEndian<Card16>>());
// "The first range must have a 'first' GID of 0."
if (begin != 0)
return error("CFF fdselect format 3 first range must have a 'first' GID of 0");
for (Card16 i = 0; i < n_ranges; i++) {
auto fd = TRY(reader.try_read<Card8>());
auto end = TRY(reader.try_read<BigEndian<Card16>>());
for (Card16 j = begin; j < end; j++)
fd_selector_array.append(fd);
begin = end;
}
// "The sentinel GID is set equal to the number of glyphs in the font."
if (begin != glyph_count)
return error("CFF fdselect format 3 last range must end at the number of glyphs in the font");
} else {
dbgln("CFF: Unknown fdselect format {}", format);
}
return fd_selector_array;
}
PDFErrorOr<Vector<CFF::Glyph>> CFF::parse_charstrings(Reader&& reader, Vector<ByteBuffer> const& local_subroutines, Vector<ByteBuffer> const& global_subroutines)
{
// CFF spec, "14 CharStrings INDEX"

1
Userland/Libraries/LibPDF/Fonts/CFF.h
View File

@ -124,6 +124,7 @@ public:
static DeprecatedFlyString resolve_sid(SID, Vector<StringView> const&);
static PDFErrorOr<Vector<SID>> parse_charset(Reader&&, size_t);
static PDFErrorOr<Vector<u8>> parse_fdselect(Reader&&, size_t);
static PDFErrorOr<Vector<u8>> parse_encoding(Reader&&, HashMap<Card8, SID>& supplemental);
};