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LibGfx/JBIG2: Add support for SDREFAGG=1 symbol segments

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...but only as long as REFAGGNINST == 1. That's enough for 0000337.pdf.
Except that it also needs GRTEMPLATE=1 support in the generic
refinement region decoding procedure, so no behaivor change yet.
This commit is contained in:
Nico Weber 2024-03-21 12:06:42 -04:00 committed by Tim Flynn
parent 3fa2ecdd65
commit ef9bfce0e7
Notes: sideshowbarker 2024-07-17 01:23:08 +09:00 
Author: https://github.com/nico
Commit: https://github.com/SerenityOS/serenity/commit/ef9bfce0e7
Pull-request: https://github.com/SerenityOS/serenity/pull/23710
Reviewed-by: https://github.com/trflynn89 ✅
1 changed files with 93 additions and 18 deletions
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111
Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp
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@ -1481,9 +1481,6 @@ static ErrorOr<Vector<NonnullRefPtr<Symbol>>> symbol_dictionary_decoding_procedu
if (inputs.uses_huffman_encoding)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode huffman symbol dictionaries yet");
if (inputs.uses_refinement_or_aggregate_coding)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode SDREFAGG symbol dictionaries yet");
auto decoder = TRY(JBIG2::ArithmeticDecoder::initialize(data));
Vector<JBIG2::ArithmeticDecoder::Context> contexts;
contexts.resize(1 << number_of_context_bits_for_template(inputs.symbol_template));
@ -1511,25 +1508,103 @@ static ErrorOr<Vector<NonnullRefPtr<Symbol>>> symbol_dictionary_decoding_procedu
// 6.5.8 Symbol bitmap
// "This field is only present if SDHUFF = 0 or SDREFAGG = 1. This field takes one of two forms; SDREFAGG
// determines which form is used."
// FIXME: Add support for SDEFRAG = 1.
// 6.5.8.2.1 Number of symbol instances in aggregation
// If SDHUFF is 1, decode a value using the Huffman table specified by SDHUFFAGGINST.
// If SDHUFF is 0, decode a value using the IAAI integer arithmetic decoding procedure (see Annex A).
// FIXME: Implement support for SDHUFF = 1.
Optional<JBIG2::ArithmeticIntegerDecoder> number_of_symbol_instances_decoder;
auto read_number_of_symbol_instances = [&]() -> i32 {
if (!number_of_symbol_instances_decoder.has_value())
number_of_symbol_instances_decoder = JBIG2::ArithmeticIntegerDecoder(decoder);
return number_of_symbol_instances_decoder->decode().value();
};
// 6.5.8.1 Direct-coded symbol bitmap
// "If SDREFAGG is 0, then decode the symbol's bitmap using a generic region decoding procedure as described in 6.2.
// Set the parameters to this decoding procedure as shown in Table 16."
auto read_bitmap = [&](u32 width, u32 height) {
GenericRegionDecodingInputParameters generic_inputs;
generic_inputs.is_modified_modified_read = false;
generic_inputs.region_width = width;
generic_inputs.region_height = height;
generic_inputs.gb_template = inputs.symbol_template;
for (int i = 0; i < 4; ++i)
generic_inputs.adaptive_template_pixels[i] = inputs.adaptive_template_pixels[i];
generic_inputs.arithmetic_decoder = &decoder;
return generic_region_decoding_procedure(generic_inputs, {}, contexts);
Optional<JBIG2::ArithmeticIntegerIDDecoder> id_decoder;
Optional<JBIG2::ArithmeticIntegerDecoder> refinement_x_offset_decoder;
Optional<JBIG2::ArithmeticIntegerDecoder> refinement_y_offset_decoder;
// FIXME: When we implement REFAGGNINST > 1 support, do these need to be shared with
// text_region_decoding_procedure() then?
Vector<JBIG2::ArithmeticDecoder::Context> refinement_contexts;
// This belongs in 6.5.5 1) below, but also needs to be captured by read_bitmap here.
Vector<NonnullRefPtr<Symbol>> new_symbols;
auto read_symbol_bitmap = [&](u32 width, u32 height) -> ErrorOr<NonnullOwnPtr<BitBuffer>> {
// "If SDREFAGG is 0, then decode the symbol's bitmap using a generic region decoding procedure as described in 6.2.
// Set the parameters to this decoding procedure as shown in Table 16."
if (!inputs.uses_refinement_or_aggregate_coding) {
// Table 16 – Parameters used to decode a symbol's bitmap using generic bitmap decoding
GenericRegionDecodingInputParameters generic_inputs;
generic_inputs.is_modified_modified_read = false;
generic_inputs.region_width = width;
generic_inputs.region_height = height;
generic_inputs.gb_template = inputs.symbol_template;
generic_inputs.is_extended_reference_template_used = false; // Missing from spec in table 16.
for (int i = 0; i < 4; ++i)
generic_inputs.adaptive_template_pixels[i] = inputs.adaptive_template_pixels[i];
generic_inputs.arithmetic_decoder = &decoder;
return generic_region_decoding_procedure(generic_inputs, {}, contexts);
}
// 6.5.8.2 Refinement/aggregate-coded symbol bitmap
// "1) Decode the number of symbol instances contained in the aggregation, as specified in 6.5.8.2.1. Let REFAGGNINST be the value decoded."
auto number_of_symbol_instances = read_number_of_symbol_instances(); // "REFAGGNINST" in spec.
dbgln_if(JBIG2_DEBUG, "Number of symbol instances: {}", number_of_symbol_instances);
if (number_of_symbol_instances > 1) {
// "2) If REFAGGNINST is greater than one, then decode the bitmap itself using a text region decoding procedure
// as described in 6.4. Set the parameters to this decoding procedure as shown in Table 17."
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode symbol bitmaps with more than one symbol instance yet");
}
// "3) If REFAGGNINST is equal to one, then decode the bitmap as described in 6.5.8.2.2."
// 6.5.8.2.3 Setting SBSYMCODES and SBSYMCODELEN
// FIXME: Implement support for SDHUFF = 1
u32 code_length = ceil(log2(inputs.input_symbols.size() + inputs.number_of_new_symbols));
// 6.5.8.2.2 Decoding a bitmap when REFAGGNINST = 1
// FIXME: This is missing some setps for the SDHUFF = 1 case.
if (number_of_symbol_instances != 1)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Unexpected number of symbol instances");
if (!id_decoder.has_value())
id_decoder = JBIG2::ArithmeticIntegerIDDecoder(decoder, code_length);
u32 symbol_id = id_decoder->decode();
if (!refinement_x_offset_decoder.has_value())
refinement_x_offset_decoder = JBIG2::ArithmeticIntegerDecoder(decoder);
i32 refinement_x_offset = refinement_x_offset_decoder->decode().value();
if (!refinement_y_offset_decoder.has_value())
refinement_y_offset_decoder = JBIG2::ArithmeticIntegerDecoder(decoder);
i32 refinement_y_offset = refinement_y_offset_decoder->decode().value();
if (symbol_id >= inputs.input_symbols.size() && symbol_id - inputs.input_symbols.size() >= new_symbols.size())
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Refinement/aggregate symbol ID out of range");
auto IBO = (symbol_id < inputs.input_symbols.size()) ? inputs.input_symbols[symbol_id] : new_symbols[symbol_id - inputs.input_symbols.size()];
// Table 18 – Parameters used to decode a symbol's bitmap when REFAGGNINST = 1
GenericRefinementRegionDecodingInputParameters refinement_inputs;
refinement_inputs.region_width = width;
refinement_inputs.region_height = height;
refinement_inputs.gr_template = inputs.refinement_template;
refinement_inputs.reference_bitmap = &IBO->bitmap();
refinement_inputs.reference_x_offset = refinement_x_offset;
refinement_inputs.reference_y_offset = refinement_y_offset;
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);
return generic_refinement_region_decoding_procedure(refinement_inputs, decoder, refinement_contexts);
};
// 6.5.5 Decoding the symbol dictionary
// "1) Create an array SDNEWSYMS of bitmaps, having SDNUMNEWSYMS entries."
Vector<NonnullRefPtr<Symbol>> new_symbols;
// Done above read_bitmap().
// "2) If SDHUFF is 1 and SDREFAGG is 0, create an array SDNEWSYMWIDTHS of integers, having SDNUMNEWSYMS entries."
// FIXME: Implement support for SDHUFF = 1.
@ -1574,7 +1649,7 @@ static ErrorOr<Vector<NonnullRefPtr<Symbol>>> symbol_dictionary_decoding_procedu
// SDNEWSYMS[NSYMSDECODED] = BS"
// FIXME: Implement support for SDHUFF = 1.
// FIXME: Doing this eagerly is pretty wasteful. Decode on demand instead?
auto bitmap = TRY(read_bitmap(symbol_width, height_class_height));
auto bitmap = TRY(read_symbol_bitmap(symbol_width, height_class_height));
new_symbols.append(Symbol::create(move(bitmap)));
// "iii) If SDHUFF is 1 and SDREFAGG is 0, then set: