119 lines
4.4 KiB
C++
119 lines
4.4 KiB
C++
/*
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* Copyright (c) 2023, Nico Weber <thakis@chromium.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibPDF/CommonNames.h>
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#include <LibPDF/Document.h>
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#include <LibPDF/Function.h>
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#include <LibPDF/ObjectDerivatives.h>
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// PDF 1.7 spec, 3.9 Functions
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namespace PDF {
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struct Bound {
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float lower;
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float upper;
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};
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class SampledFunction final : public Function {
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public:
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virtual PDFErrorOr<ReadonlySpan<float>> evaluate(ReadonlySpan<float>) const override;
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};
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PDFErrorOr<ReadonlySpan<float>> SampledFunction::evaluate(ReadonlySpan<float>) const
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{
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return Error(Error::Type::RenderingUnsupported, "SampledFunction not yet implemented"_string);
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}
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class ExponentialInterpolationFunction final : public Function {
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public:
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virtual PDFErrorOr<ReadonlySpan<float>> evaluate(ReadonlySpan<float>) const override;
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};
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PDFErrorOr<ReadonlySpan<float>> ExponentialInterpolationFunction::evaluate(ReadonlySpan<float>) const
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{
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return Error(Error::Type::RenderingUnsupported, "ExponentialInterpolationFunction not yet implemented"_string);
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}
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class StitchingFunction final : public Function {
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public:
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virtual PDFErrorOr<ReadonlySpan<float>> evaluate(ReadonlySpan<float>) const override;
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};
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PDFErrorOr<ReadonlySpan<float>> StitchingFunction::evaluate(ReadonlySpan<float>) const
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{
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return Error(Error::Type::RenderingUnsupported, "StitchingFunction not yet implemented"_string);
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}
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class PostScriptCalculatorFunction final : public Function {
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public:
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virtual PDFErrorOr<ReadonlySpan<float>> evaluate(ReadonlySpan<float>) const override;
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};
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PDFErrorOr<ReadonlySpan<float>> PostScriptCalculatorFunction::evaluate(ReadonlySpan<float>) const
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{
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return Error(Error::Type::RenderingUnsupported, "PostScriptCalculatorFunction not yet implemented"_string);
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}
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PDFErrorOr<NonnullRefPtr<Function>> Function::create(Document* document, NonnullRefPtr<Object> object)
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{
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if (!object->is<DictObject>() && !object->is<StreamObject>())
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return Error { Error::Type::MalformedPDF, "Function object must be dict or stream" };
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auto function_dict = object->is<DictObject>() ? object->cast<DictObject>() : object->cast<StreamObject>()->dict();
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// "TABLE 3.35 Entries common to all function dictionaries"
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if (!function_dict->contains(CommonNames::FunctionType))
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return Error { Error::Type::MalformedPDF, "Function requires /FunctionType" };
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auto function_type = TRY(document->resolve_to<int>(function_dict->get_value(CommonNames::FunctionType)));
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if (!function_dict->contains(CommonNames::Domain))
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return Error { Error::Type::MalformedPDF, "Function requires /Domain" };
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auto domain_array = TRY(function_dict->get_array(document, CommonNames::Domain));
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if (domain_array->size() % 2 != 0)
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return Error { Error::Type::MalformedPDF, "Function /Domain size not multiple of 2" };
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Vector<Bound> domain;
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for (size_t i = 0; i < domain_array->size(); i += 2) {
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domain.append({ domain_array->at(i).to_float(), domain_array->at(i + 1).to_float() });
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if (domain.last().lower > domain.last().upper)
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return Error { Error::Type::MalformedPDF, "Function /Domain lower bound > upper bound" };
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}
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// Can't use PDFErrorOr with Optional::map()
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Optional<Vector<Bound>> optional_range;
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if (function_dict->contains(CommonNames::Range)) {
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auto range_array = TRY(function_dict->get_array(document, CommonNames::Range));
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if (range_array->size() % 2 != 0)
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return Error { Error::Type::MalformedPDF, "Function /Range size not multiple of 2" };
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Vector<Bound> range;
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for (size_t i = 0; i < range_array->size(); i += 2) {
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range.append({ range_array->at(i).to_float(), range_array->at(i + 1).to_float() });
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if (range.last().lower > range.last().upper)
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return Error { Error::Type::MalformedPDF, "Function /Range lower bound > upper bound" };
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}
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optional_range = move(range);
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}
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switch (function_type) {
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case 0:
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return adopt_ref(*new SampledFunction());
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// The spec has no entry for `1`.
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case 2:
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return adopt_ref(*new ExponentialInterpolationFunction());
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case 3:
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return adopt_ref(*new StitchingFunction());
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case 4:
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return adopt_ref(*new PostScriptCalculatorFunction());
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default:
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dbgln("invalid function type {}", function_type);
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return Error(Error::Type::MalformedPDF, "Function has unkonwn type"_string);
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}
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}
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}
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