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LibPDF+LibGfx: Support JBIG2s with /JBIG2Globals set

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Several ramifications:

* /JBIG2Globals is an indirect reference, which means we now need
  a Document for unfiltering. (Technically, other decode parameters
  can also be indirect objects and we should use the Document to
  resolve() those too, but in practice it only seems to be needed
  for /JBIG2Globals.)

* Since /JBIG2Globals are so rare, we just parse once for each
  image that use them, and decode_embedded() now receives a
  Vector<ReadonlyBytes> with all sections of sequences of
  segments.

* Internally, decode_segment_headers() is now called several times
  for embedded JBIG2s with multiple such sections (e.g. PDFs with
  /JBIG2Globals).

* That means `data` is now no longer part of JBIG2LoadingContext
  and things get slightly reshuffled due to this.

This completes the LibPDF part of JBIG2 support. Once LibGfx
implements actual decoding of JBIG2s, things should start to
Just Work in PDFs.
This commit is contained in:
Nico Weber 2024-03-03 21:54:00 -05:00 • committed by Andreas Kling
parent 09ca66cb8b
commit 1eaaa8c3e9
5 changed files with 32 additions and 28 deletions
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2
Userland/Libraries/LibPDF/Parser.cpp
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@ -460,7 +460,7 @@ PDFErrorOr<void> Parser::unfilter_stream(NonnullRefPtr<StreamObject> stream_obje
if (!decode_parms_vector.is_empty())
decode_parms = decode_parms_vector.at(i);
stream_object->buffer() = TRY(Filter::decode(stream_object->bytes(), filters.at(i), decode_parms));
stream_object->buffer() = TRY(Filter::decode(m_document, stream_object->bytes(), filters.at(i), decode_parms));
}
return {};