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https://github.com/JakubMelka/PDF4QT.git
synced 2025-06-05 21:59:17 +02:00
Document content flow basics
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Jakub Melka
@ -505,6 +505,19 @@ std::vector<PDFObjectReference> PDFStructureTree::getParents(PDFInteger id) cons
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return result;
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}
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PDFObjectReference PDFStructureTree::getParent(PDFInteger id, PDFInteger index) const
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{
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Q_ASSERT(std::is_sorted(m_parentTreeEntries.cbegin(), m_parentTreeEntries.cend()));
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ParentTreeEntry entry{ id, PDFObjectReference() };
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auto [it, itEnd] = std::equal_range(m_parentTreeEntries.cbegin(), m_parentTreeEntries.cend(), entry);
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const PDFInteger count = std::distance(it, itEnd);
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if (index >= 0 && index < count)
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{
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return (*std::next(it, index)).reference;
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}
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return PDFObjectReference();
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}
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PDFStructureItem::Type PDFStructureTree::getTypeFromRole(const QByteArray& role) const
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{
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auto it = m_roleMap.find(role);
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@ -556,16 +569,14 @@ PDFStructureTree PDFStructureTree::parse(const PDFObjectStorage* storage, PDFObj
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return id < other.id;
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}
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static ParentTreeParseEntry parse(PDFInteger id, const PDFObjectStorage*, const PDFObject& object)
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static ParentTreeParseEntry parse(PDFInteger id, const PDFObjectStorage* storage, const PDFObject& object)
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{
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if (object.isReference())
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{
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return ParentTreeParseEntry{ id, { object.getReference() } };
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}
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else if (object.isArray())
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const PDFObject& dereferencedObject = storage->getObject(object);
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if (dereferencedObject.isArray())
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{
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std::vector<PDFObjectReference> references;
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for (const PDFObject& object : *object.getArray())
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for (const PDFObject& object : *dereferencedObject.getArray())
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{
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if (object.isReference())
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{
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@ -575,6 +586,10 @@ PDFStructureTree PDFStructureTree::parse(const PDFObjectStorage* storage, PDFObj
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return ParentTreeParseEntry{ id, qMove(references) };
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}
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else if (object.isReference())
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{
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return ParentTreeParseEntry{ id, { object.getReference() } };
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}
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return ParentTreeParseEntry{ id, { } };
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}
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@ -629,6 +644,16 @@ PDFStructureTree PDFStructureTree::parse(const PDFObjectStorage* storage, PDFObj
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return tree;
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}
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PDFStructureTree::ParentTreeEntry PDFStructureTree::getParentTreeEntry(PDFInteger index) const
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{
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if (index >= 0 && index < PDFInteger(m_parentTreeEntries.size()))
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{
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return m_parentTreeEntries[index];
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}
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return ParentTreeEntry();
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}
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PDFStructureItemPointer PDFStructureItem::parse(const PDFObjectStorage* storage, PDFObject object, PDFMarkedObjectsContext* context, PDFStructureItem* parent)
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{
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if (const PDFDictionary* dictionary = storage->getDictionaryFromObject(object))
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@ -939,237 +964,4 @@ void PDFStructureTreeAbstractVisitor::acceptChildren(const PDFStructureItem* ite
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}
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}
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class PDFStructureTreeReferenceCollector : public PDFStructureTreeAbstractVisitor
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{
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public:
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explicit inline PDFStructureTreeReferenceCollector(std::map<PDFObjectReference, const PDFStructureItem*>* mapping) :
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m_mapping(mapping)
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{
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}
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virtual void visitStructureTree(const PDFStructureTree* structureTree) override;
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virtual void visitStructureElement(const PDFStructureElement* structureElement) override;
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virtual void visitStructureMarkedContentReference(const PDFStructureMarkedContentReference* structureMarkedContentReference) override;
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virtual void visitStructureObjectReference(const PDFStructureObjectReference* structureObjectReference) override;
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private:
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void addReference(const PDFStructureItem* structureObjectReference);
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std::map<PDFObjectReference, const PDFStructureItem*>* m_mapping;
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};
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void PDFStructureTreeReferenceCollector::visitStructureTree(const PDFStructureTree* structureTree)
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{
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addReference(structureTree);
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acceptChildren(structureTree);
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}
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void PDFStructureTreeReferenceCollector::visitStructureElement(const PDFStructureElement* structureElement)
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{
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addReference(structureElement);
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acceptChildren(structureElement);
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}
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void PDFStructureTreeReferenceCollector::visitStructureMarkedContentReference(const PDFStructureMarkedContentReference* structureMarkedContentReference)
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{
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addReference(structureMarkedContentReference);
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acceptChildren(structureMarkedContentReference);
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}
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void PDFStructureTreeReferenceCollector::visitStructureObjectReference(const PDFStructureObjectReference* structureObjectReference)
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{
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addReference(structureObjectReference);
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acceptChildren(structureObjectReference);
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}
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void PDFStructureTreeReferenceCollector::addReference(const PDFStructureItem* structureItem)
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{
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if (structureItem->getSelfReference().isValid())
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{
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(*m_mapping)[structureItem->getSelfReference()] = structureItem;
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}
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}
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class PDFStructureTreeTextContentProcessor : public PDFPageContentProcessor
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{
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using BaseClass = PDFPageContentProcessor;
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public:
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explicit PDFStructureTreeTextContentProcessor(PDFRenderer::Features features,
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const PDFPage* page,
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const PDFDocument* document,
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const PDFFontCache* fontCache,
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const PDFCMS* cms,
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const PDFOptionalContentActivity* optionalContentActivity,
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QMatrix pagePointToDevicePointMatrix,
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const PDFMeshQualitySettings& meshQualitySettings) :
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BaseClass(page, document, fontCache, cms, optionalContentActivity, pagePointToDevicePointMatrix, meshQualitySettings),
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m_features(features)
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{
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}
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std::map<PDFInteger, QStringList>& takeTexts() { return m_text; }
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QStringList& takeUnmatchedTexts() { return m_unmatchedText; }
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protected:
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virtual bool isContentSuppressedByOC(PDFObjectReference ocgOrOcmd) override;
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virtual bool isContentKindSuppressed(ContentKind kind) const override;
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virtual void performOutputCharacter(const PDFTextCharacterInfo& info) override;
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virtual void performMarkedContentBegin(const QByteArray& tag, const PDFObject& properties) override;
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virtual void performMarkedContentEnd() override;
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private:
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struct MarkedContentInfo
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{
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QByteArray tag;
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PDFInteger mcid = -1;
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};
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PDFRenderer::Features m_features;
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std::vector<MarkedContentInfo> m_markedContentInfoStack;
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QString m_currentText;
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std::map<PDFInteger, QStringList> m_text;
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QStringList m_unmatchedText;
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};
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void PDFStructureTreeTextContentProcessor::performMarkedContentBegin(const QByteArray& tag, const PDFObject& properties)
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{
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MarkedContentInfo info;
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info.tag = tag;
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if (properties.isDictionary())
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{
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const PDFDictionary* dictionary = properties.getDictionary();
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PDFObject mcid = dictionary->get("MCID");
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if (mcid.isInt())
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{
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info.mcid = mcid.getInteger();
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}
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}
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m_markedContentInfoStack.emplace_back(qMove(info));
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}
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void PDFStructureTreeTextContentProcessor::performMarkedContentEnd()
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{
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MarkedContentInfo info = qMove(m_markedContentInfoStack.back());
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m_markedContentInfoStack.pop_back();
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if (info.mcid != -1)
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{
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if (!m_currentText.isEmpty())
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{
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m_text[info.mcid].push_back(qMove(m_currentText));
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}
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m_currentText = QString();
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}
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if (m_markedContentInfoStack.empty() && !m_currentText.isEmpty())
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{
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m_unmatchedText << qMove(m_currentText);
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m_currentText = QString();
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}
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}
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bool PDFStructureTreeTextContentProcessor::isContentSuppressedByOC(PDFObjectReference ocgOrOcmd)
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{
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if (m_features.testFlag(PDFRenderer::IgnoreOptionalContent))
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{
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return false;
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}
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return PDFPageContentProcessor::isContentSuppressedByOC(ocgOrOcmd);
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}
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bool PDFStructureTreeTextContentProcessor::isContentKindSuppressed(ContentKind kind) const
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{
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switch (kind)
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{
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case ContentKind::Shapes:
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case ContentKind::Text:
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case ContentKind::Images:
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case ContentKind::Shading:
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return true;
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case ContentKind::Tiling:
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return false; // Tiling can have text
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default:
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{
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Q_ASSERT(false);
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break;
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}
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}
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return false;
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}
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void PDFStructureTreeTextContentProcessor::performOutputCharacter(const PDFTextCharacterInfo& info)
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{
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if (!isContentSuppressed())
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{
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if (!info.character.isNull())
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{
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m_currentText.push_back(info.character);
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}
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}
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}
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PDFStructureTreeTextExtractor::PDFStructureTreeTextExtractor(const PDFDocument* document, const PDFStructureTree* tree) :
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m_document(document),
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m_tree(tree)
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{
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}
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void PDFStructureTreeTextExtractor::perform(const std::vector<PDFInteger>& pageIndices)
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{
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std::map<PDFObjectReference, const PDFStructureItem*> mapping;
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PDFStructureTreeReferenceCollector referenceCollector(&mapping);
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m_tree->accept(&referenceCollector);
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PDFFontCache fontCache(DEFAULT_FONT_CACHE_LIMIT, DEFAULT_REALIZED_FONT_CACHE_LIMIT);
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// Jakub Melka: maps text to structure tree items. Key is pair of (page index, mcid)
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std::map<std::pair<PDFInteger, PDFInteger>, QStringList> extractedText;
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QMutex mutex;
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PDFCMSGeneric cms;
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PDFMeshQualitySettings mqs;
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PDFOptionalContentActivity oca(m_document, OCUsage::Export, nullptr);
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pdf::PDFModifiedDocument md(const_cast<PDFDocument*>(m_document), &oca);
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fontCache.setDocument(md);
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fontCache.setCacheShrinkEnabled(nullptr, false);
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auto generateTextLayout = [this, &mutex, &extractedText, &fontCache, &cms, &mqs, &oca](PDFInteger pageIndex)
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{
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const PDFCatalog* catalog = m_document->getCatalog();
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if (!catalog->getPage(pageIndex))
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{
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// Invalid page index
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return;
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}
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const PDFPage* page = catalog->getPage(pageIndex);
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Q_ASSERT(page);
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PDFStructureTreeTextContentProcessor processor(PDFRenderer::IgnoreOptionalContent, page, m_document, &fontCache, &cms, &oca, QMatrix(), mqs);
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QList<PDFRenderError> errors = processor.processContents();
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QMutexLocker lock(&mutex);
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for (auto& item : processor.takeTexts())
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{
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extractedText[std::make_pair(pageIndex, item.first)].append(qMove(item.second));
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}
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m_unmatchedText << qMove(processor.takeUnmatchedTexts());
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m_errors.append(qMove(errors));
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};
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PDFExecutionPolicy::execute(PDFExecutionPolicy::Scope::Page, pageIndices.begin(), pageIndices.end(), generateTextLayout);
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fontCache.setCacheShrinkEnabled(nullptr, true);
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}
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} // namespace pdf
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