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LibPDF: In Filter::decode_jbig2(), invert bits

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Nico Weber 2024-03-08 21:17:20 -05:00 • committed by Tim Flynn
parent 54dcb17062
commit be9a6caa0a
1 changed files with 8 additions and 1 deletions
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9
Userland/Libraries/LibPDF/Filter.cpp
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@ -346,7 +346,14 @@ PDFErrorOr<ByteBuffer> Filter::decode_jbig2(Document* document, ReadonlyBytes by
} }
segments.append(bytes); segments.append(bytes);
return TRY(Gfx::JBIG2ImageDecoderPlugin::decode_embedded(segments)); auto decoded = TRY(Gfx::JBIG2ImageDecoderPlugin::decode_embedded(segments));
// JBIG2 treats `1` as "ink present" (black) and `0` as "no ink" (white).
// PDF treats `1` as "light present" (white) and `1` as "no light" (black).
// So we have to invert.
invert_bits(decoded);
return decoded;
} }
PDFErrorOr<ByteBuffer> Filter::decode_dct(ReadonlyBytes bytes) PDFErrorOr<ByteBuffer> Filter::decode_dct(ReadonlyBytes bytes)