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LibGfx/JBIG2: Add support for refinement coding template 1

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This is used when refining a symbol in 0000337.pdf.
This commit is contained in:
Nico Weber 2024-03-21 12:14:41 -04:00 committed by Tim Flynn
parent ef9bfce0e7
commit 7dd5457b8f
Notes: sideshowbarker 2024-07-16 23:08:48 +09:00 
Author: https://github.com/nico
Commit: https://github.com/SerenityOS/serenity/commit/7dd5457b8f
Pull-request: https://github.com/SerenityOS/serenity/pull/23710
Reviewed-by: https://github.com/trflynn89 ✅
1 changed files with 24 additions and 6 deletions
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30
Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp
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@ -1092,9 +1092,6 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
}
// GRTEMPLATE 1 never uses adaptive pixels.
if (inputs.gr_template == 1)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode GRTEMPLATE 1 yet");
// 6.3.5.3 Fixed templates and adaptive templates
static constexpr auto get_pixel = [](BitBuffer const& buffer, int x, int y) -> bool {
if (x < 0 || x >= (int)buffer.width() || y < 0 || y >= (int)buffer.height())
@ -1103,7 +1100,7 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
};
// Figure 12 – 13-pixel refinement template showing the AT pixels at their nominal locations
constexpr auto compute_context = [](BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
constexpr auto compute_context_0 = [](BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
u16 result = 0;
for (int dy = -1; dy <= 1; ++dy)
@ -1117,6 +1114,27 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
return result;
};
// Figure 13 – 10-pixel refinement template
constexpr auto compute_context_1 = [](BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
u16 result = 0;
for (int dy = -1; dy <= 1; ++dy) {
for (int dx = -1; dx <= 1; ++dx) {
if ((dy == -1 && (dx == -1 || dx == 1)) || (dy == 1 && dx == -1))
continue;
result = (result << 1) | (u16)get_pixel(reference, reference_x + dx, reference_y + dy);
}
}
for (int i = 0; i < 3; ++i)
result = (result << 1) | (u16)get_pixel(buffer, x - 1 + i, y - 1);
result = (result << 1) | (u16)get_pixel(buffer, x - 1, y);
return result;
};
auto compute_context = inputs.gr_template == 0 ? compute_context_0 : compute_context_1;
// 6.3.5.6 Decoding the refinement bitmap
auto result = TRY(BitBuffer::create(inputs.region_width, inputs.region_height));
for (size_t y = 0; y < result->height(); ++y) {
@ -1257,7 +1275,7 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> text_region_decoding_procedure(TextRegi
JBIG2::ArithmeticIntegerDecoder has_refinement_image_decoder(decoder);
Vector<JBIG2::ArithmeticDecoder::Context> refinement_contexts;
if (inputs.uses_refinement_coding)
refinement_contexts.resize(1 << 13);
refinement_contexts.resize(1 << (inputs.refinement_template == 0 ? 13 : 10));
OwnPtr<BitBuffer> refinement_result;
auto read_bitmap = [&](u32 id) -> ErrorOr<BitBuffer const*> {
if (id >= inputs.symbols.size())
@ -1598,7 +1616,7 @@ static ErrorOr<Vector<NonnullRefPtr<Symbol>>> symbol_dictionary_decoding_procedu
refinement_inputs.is_typical_prediction_used = false;
refinement_inputs.adaptive_template_pixels = inputs.refinement_adaptive_template_pixels;
if (refinement_contexts.is_empty())
refinement_contexts.resize(1 << 13);
refinement_contexts.resize(1 << (inputs.refinement_template == 0 ? 13 : 10));
return generic_refinement_region_decoding_procedure(refinement_inputs, decoder, refinement_contexts);
};