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LibGfx/TIFF+CCITT: Clarify naming of compression type 2

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Type 2 <=> One-dimensional Group3, customized for TIFF
Type 3 <=> Two-dimensional Group3, uses the original 1D internally
Type 4 <=> Two-dimensional Group4

So let's clarify that this is not Group3 1D but the TIFF variant, which
is called `CCITTRLE` in libtiff. So let's stick with this name to avoid
confusion.
This commit is contained in:
Lucas CHOLLET 2024-01-15 00:46:10 -05:00 • committed by Andreas Kling
parent 9b50b5793b
commit edffdc35a9
6 changed files with 9 additions and 9 deletions
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4
Tests/LibGfx/TestImageDecoder.cpp
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@ -543,9 +543,9 @@ TEST_CASE(test_tiff_uncompressed)
EXPECT_EQ(frame.image->get_pixel(60, 75), Gfx::Color::NamedColor::Red);
}
TEST_CASE(test_tiff_ccitt3_1d)
TEST_CASE(test_tiff_ccitt_rle)
{
auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("tiff/ccitt3_1d.tiff"sv)));
auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("tiff/ccitt_rle.tiff"sv)));
EXPECT(Gfx::TIFFImageDecoderPlugin::sniff(file->bytes()));
auto plugin_decoder = TRY_OR_FAIL(Gfx::TIFFImageDecoderPlugin::create(file->bytes()));

0
Tests/LibGfx/test-inputs/tiff/ccitt3_1d.tiff → Tests/LibGfx/test-inputs/tiff/ccitt_rle.tiff
View file

2
Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.cpp
View file

@ -266,7 +266,7 @@ Optional<Code> get_terminal_code(Color color, u16 code_word, u8 code_size)
}
ErrorOr<ByteBuffer> decode_ccitt3_1d(ReadonlyBytes bytes, u32 image_width, u32 image_height)
ErrorOr<ByteBuffer> decode_ccitt_rle(ReadonlyBytes bytes, u32 image_width, u32 image_height)
{
auto strip_stream = make<FixedMemoryStream>(bytes);
auto bit_stream = make<BigEndianInputBitStream>(MaybeOwned<Stream>(*strip_stream));

2
Userland/Libraries/LibGfx/ImageFormats/CCITTDecoder.h
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@ -21,6 +21,6 @@ namespace Gfx::CCITT {
// However, this function implements the TIFF variant (see TIFFLoader.h for a spec link),
// differences are detailed in section:
// Section 10: Modified Huffman Compression
ErrorOr<ByteBuffer> decode_ccitt3_1d(ReadonlyBytes bytes, u32 image_width, u32 image_height);
ErrorOr<ByteBuffer> decode_ccitt_rle(ReadonlyBytes bytes, u32 image_width, u32 image_height);
}

8
Userland/Libraries/LibGfx/ImageFormats/TIFFLoader.cpp
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@ -281,17 +281,17 @@ private:
TRY(loop_over_pixels(move(identity)));
break;
}
case Compression::CCITT: {
case Compression::CCITTRLE: {
TRY(ensure_tags_are_correct_for_ccitt());
ByteBuffer decoded_bytes {};
auto decode_ccitt_1D_strip = [&](u32 num_bytes) -> ErrorOr<ReadonlyBytes> {
auto decode_ccitt_rle_strip = [&](u32 num_bytes) -> ErrorOr<ReadonlyBytes> {
auto const encoded_bytes = TRY(m_stream->read_in_place<u8 const>(num_bytes));
decoded_bytes = TRY(CCITT::decode_ccitt3_1d(encoded_bytes, *m_metadata.image_width(), *m_metadata.rows_per_strip()));
decoded_bytes = TRY(CCITT::decode_ccitt_rle(encoded_bytes, *m_metadata.image_width(), *m_metadata.rows_per_strip()));
return decoded_bytes;
};
TRY(loop_over_pixels(move(decode_ccitt_1D_strip)));
TRY(loop_over_pixels(move(decode_ccitt_rle_strip)));
break;
}
case Compression::LZW: {

2
Userland/Libraries/LibGfx/TIFFGenerator.py
View file

@ -51,7 +51,7 @@ class Predictor(EnumWithExportName):
class Compression(EnumWithExportName):
NoCompression = 1
CCITT = 2
CCITTRLE = 2
Group3Fax = 3
Group4Fax = 4
LZW = 5