Issue #118: First part of splitting

Pdf4QtLibCore/sources/pdfdocumentmanipulator.h

@@ -0,0 +1,160 @@
+//    Copyright (C) 2021 Jakub Melka
+//
+//    This file is part of PDF4QT.
+//
+//    PDF4QT is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    with the written consent of the copyright owner, any later version.
+//
+//    PDF4QT is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDF4QT.  If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef PDFDOCUMENTMANIPULATOR_H
+#define PDFDOCUMENTMANIPULATOR_H
+
+#include "pdfdocument.h"
+#include "pdfutils.h"
+
+#include <QImage>
+
+namespace pdf
+{
+
+/// Document page assembler/manipulator. Can assemble document(s) pages
+/// to a new document, where pages are inserted/removed/moved, or joined
+/// from another documents, or blank pages/image pages inserted. Document
+/// is also optimized.
+class PDF4QTLIBSHARED_EXPORT PDFDocumentManipulator
+{
+    Q_DECLARE_TR_FUNCTIONS(pdf::PDFDocumentManipulator)
+
+public:
+    explicit PDFDocumentManipulator() = default;
+
+    /// Selects outline creation mode, when multiple documents
+    /// are merged into one. For single document manipulation,
+    /// this has no meaning.
+    enum class OutlineMode
+    {
+        NoOutline,
+        Join,
+        DocumentParts
+    };
+
+    struct AssembledPage
+    {
+        PDFInteger documentIndex = -1; ///< Source document index. If page is not from a document, value is -1.
+        PDFInteger imageIndex = -1; ///< Source image index. If page is not from a image, value is -1.
+        PDFInteger pageIndex = -1; ///< Source document page index. If page is not from a document, value is -1.
+        QSizeF pageSize; ///< Unrotated page size
+        PageRotation pageRotation = PageRotation::None; ///< Page rotation
+
+        constexpr bool isDocumentPage() const { return documentIndex != -1; }
+        constexpr bool isImagePage() const { return imageIndex != -1; }
+        constexpr bool isBlankPage() const { return documentIndex == -1 && imageIndex == -1; }
+    };
+
+    using AssembledPages = std::vector<AssembledPage>;
+
+    /// Adds document with given index to available document list
+    /// \param documentIndex Document index
+    /// \param document Document
+    void addDocument(int documentIndex, const PDFDocument* document) { m_documents[documentIndex] = document; }
+
+    /// Adds image with given index to available image list
+    /// \param imageIndex Image index
+    /// \param image Image
+    void addImage(int imageIndex, QImage image) { m_images[imageIndex] = std::move(image); }
+
+    /// Assembles pages into a new document. Returns true, if a new document
+    /// was assembled, otherwise error message is being returned. Assebmled
+    /// document can be accessed trough a given getters.
+    /// \param pages Pages
+    /// \returns True or error message
+    PDFOperationResult assemble(const AssembledPages& pages);
+
+    /// Returns reference to an assembled document. This function should
+    /// be called only, if method \p assemble returns true, otherwise
+    /// undefined document can be returned.
+    /// \returns Assembled document
+    const PDFDocument& getAssembledDocument() const { return m_assembledDocument; }
+
+    /// Returns rvalue reference to an assembled document. This function should
+    /// be called only, if method \p assemble returns true, otherwise
+    /// undefined document can be returned.
+    /// \returns Assembled document
+    PDFDocument&& takeAssembledDocument() { return std::move(m_assembledDocument); }
+
+    static AssembledPages createAllDocumentPages(int documentIndex, const PDFDocument* document);
+
+    static constexpr AssembledPage createDocumentPage(int documentIndex, int pageIndex, QSizeF pageSize, PageRotation pageRotation) { return AssembledPage{ documentIndex, -1, pageIndex, pageSize, pageRotation}; }
+    static constexpr AssembledPage createImagePage(int imageIndex, QSizeF pageSize, PageRotation pageRotation) { return AssembledPage{ -1, imageIndex, -1, pageSize, pageRotation}; }
+    static constexpr AssembledPage createBlankPage(QSizeF pageSize, PageRotation pageRotation) { return AssembledPage{ -1, -1, -1, pageSize, pageRotation}; }
+
+    OutlineMode getOutlineMode() const;
+    void setOutlineMode(OutlineMode outlineMode);
+
+private:
+
+    struct ProcessedPage
+    {
+        AssembledPage assembledPage;
+        PDFObjectReference targetPageReference;
+    };
+
+    using ProcessedPages = std::vector<ProcessedPage>;
+
+    enum AssembleFlag
+    {
+        None            = 0x0000,
+        SingleDocument  = 0x0001, ///< We are assembling a single page document (possibly with blank pages / image pages
+        RemovedPages    = 0x0002, ///< Document contains removed pages
+    };
+    Q_DECLARE_FLAGS(AssembleFlags, AssembleFlag)
+
+    enum MergedObjectType
+    {
+        MOT_OCProperties,
+        MOT_Form,
+        MOT_Names,
+        MOT_Last
+    };
+
+    /// Processes pages given a page list and a document builder.
+    /// \param documentBuilder Document builder
+    /// \param pages Pages to be processed
+    /// \returns Processed pages
+    ProcessedPages processPages(PDFDocumentBuilder& documentBuilder, const AssembledPages& pages);
+
+    /// Collects objects and copies them into the target document builder.
+    /// \param documentBuilder Document builder
+    /// \param pages Pages to be copied
+    /// \returns Processed pages
+    ProcessedPages collectObjectsAndCopyPages(PDFDocumentBuilder& documentBuilder, const AssembledPages& pages);
+
+    void classify(const AssembledPages& pages);
+    void initializeMergedObjects(PDFDocumentBuilder& documentBuilder);
+    void finalizeMergedObjects(PDFDocumentBuilder& documentBuilder);
+    void finalizeDocument(PDFDocument* document);
+    void addOutlineAndDocumentParts(PDFDocumentBuilder& documentBuilder,
+                                    const AssembledPages& pages,
+                                    const std::vector<PDFObjectReference>& adjustedPages);
+
+    std::map<PDFInteger, const PDFDocument*> m_documents;
+    std::map<PDFInteger, QImage> m_images;
+    AssembleFlags m_flags = None;
+    std::array<PDFObjectReference, MOT_Last> m_mergedObjects = { };
+    PDFDocument m_assembledDocument;
+    OutlineMode m_outlineMode = OutlineMode::DocumentParts;
+    std::map<PDFInteger, PDFObjectReference> m_outlines;
+};
+
+}   // namespace pdf
+
+#endif // PDFDOCUMENTMANIPULATOR_H