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LibGfx/JBIG2: Implement generic_refinement_region_decoding_procedure()

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With this, we can decode all pages of 0000425.pdf, 0000215.pdf,
0000882.pdf, and 0000057.pdf.
This commit is contained in:
Nico Weber 2024-03-21 10:58:51 -04:00 committed by Andreas Kling
parent 0d2e91b4ea
commit d2998c1f5e
Notes: sideshowbarker 2024-07-17 09:48:50 +09:00 
Author: https://github.com/nico
Commit: https://github.com/SerenityOS/serenity/commit/d2998c1f5e
Pull-request: https://github.com/SerenityOS/serenity/pull/23696
1 changed files with 38 additions and 3 deletions
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41
Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp
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@ -964,7 +964,7 @@ struct GenericRefinementRegionDecodingInputParameters {
};
// 6.3 Generic Refinement Region Decoding Procedure
static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_procedure(GenericRefinementRegionDecodingInputParameters& inputs)
static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_procedure(GenericRefinementRegionDecodingInputParameters& inputs, JBIG2::ArithmeticDecoder& decoder, Vector<JBIG2::ArithmeticDecoder::Context>& contexts)
{
VERIFY(inputs.gr_template == 0 || inputs.gr_template == 1);
@ -981,7 +981,39 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
if (inputs.gr_template == 1)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode GRTEMPLATE 1 yet");
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode generic refinement regions 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())
return false;
return buffer.get_bit(x, y);
};
// 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 {
u16 result = 0;
for (int dy = -1; dy <= 1; ++dy)
for (int dx = -1; dx <= 1; ++dx)
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;
};
// 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) {
for (size_t x = 0; x < result->width(); ++x) {
u16 context = compute_context(*inputs.reference_bitmap, x - inputs.reference_x_offset, y - inputs.reference_y_offset, *result, x, y);
bool bit = decoder.get_next_bit(contexts[context]);
result->set_bit(x, y, bit);
}
}
return result;
}
// 6.4.2 Input parameters
@ -1120,6 +1152,9 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> text_region_decoding_procedure(TextRegi
// 6.4.11 Symbol instance bitmap
JBIG2::ArithmeticIntegerDecoder has_refinement_image_decoder(decoder);
Vector<JBIG2::ArithmeticDecoder::Context> refinement_contexts;
if (inputs.uses_refinement_coding)
refinement_contexts.resize(1 << 13);
OwnPtr<BitBuffer> refinement_result;
auto read_bitmap = [&](u32 id) -> ErrorOr<BitBuffer const*> {
if (id >= inputs.symbols.size())
@ -1155,7 +1190,7 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> text_region_decoding_procedure(TextRegi
refinement_inputs.reference_y_offset = refinement_delta_height / 2 + refinement_y_offset;
refinement_inputs.is_typical_prediction_used = false;
refinement_inputs.adaptive_template_pixels = inputs.refinement_adaptive_template_pixels;
refinement_result = TRY(generic_refinement_region_decoding_procedure(refinement_inputs));
refinement_result = TRY(generic_refinement_region_decoding_procedure(refinement_inputs, decoder, refinement_contexts));
return refinement_result.ptr();
};