XFA: form pagination

Pdf4QtLib/sources/pdfdocument.h

@@ -504,6 +504,7 @@ public:
         Annotation      = 0x0002,   ///< Annotations changed
         FormField       = 0x0004,   ///< Form field content changed
         Authorization   = 0x0008,   ///< Authorization has changed (for example, old document is granted user access, but for new, owner access)
+        XFA_Pagination  = 0x0010,   ///< XFA pagination has been performed (this flag can be set only when Reset flag has been set and not any other flag)
     };
 
     Q_DECLARE_FLAGS(ModificationFlags, ModificationFlag)

Pdf4QtLib/sources/pdfdocumentbuilder.h

@@ -1515,6 +1515,7 @@ public:
     void markReset() { m_modificationFlags.setFlag(PDFModifiedDocument::Reset); }
     void markAnnotationsChanged() { m_modificationFlags.setFlag(PDFModifiedDocument::Annotation); }
     void markFormFieldChanged() { m_modificationFlags.setFlag(PDFModifiedDocument::FormField); }
+    void markXFAPagination() { m_modificationFlags.setFlag(PDFModifiedDocument::XFA_Pagination); }
 
 private:
     const PDFDocument* m_originalDocument;

Pdf4QtLib/sources/pdfform.cpp

@@ -1668,6 +1668,75 @@ void PDFFormManager::drawXFAForm(const QMatrix& pagePointToDevicePointMatrix,
     }
 }
 
+void PDFFormManager::performPaging()
+{
+    if (!hasXFAForm() || !m_document)
+    {
+        return;
+    }
+
+    std::vector<QSizeF> pageSizes = m_xfaEngine.getPageSizes();
+
+    const PDFCatalog* catalog = m_document->getCatalog();
+    const size_t pageCount = catalog->getPageCount();
+    std::vector<QSizeF> oldPageSizes;
+    oldPageSizes.reserve(pageCount);
+
+    for (size_t i = 0; i < pageCount; ++i)
+    {
+        oldPageSizes.push_back(catalog->getPage(i)->getMediaBox().size());
+    }
+
+    bool changed = pageSizes.size() != oldPageSizes.size();
+    if (!changed)
+    {
+        for (size_t i = 0; i < pageCount; ++i)
+        {
+            changed = changed ||
+                      !qFuzzyCompare(pageSizes[i].width(), oldPageSizes[i].width()) ||
+                      !qFuzzyCompare(pageSizes[i].height(), oldPageSizes[i].height());
+        }
+    }
+
+    if (changed && !oldPageSizes.empty())
+    {
+        PDFDocumentModifier modifier(m_document);
+        modifier.getBuilder()->setFormManager(this);
+        modifier.markReset();
+
+        PDFDocumentBuilder* builder = modifier.getBuilder();
+        builder->flattenPageTree();
+        std::vector<PDFObjectReference> pages = builder->getPages();
+
+        // Do we have more pages?
+        if (pages.size() > pageSizes.size())
+        {
+            pages.resize(pageSizes.size());
+        }
+
+        // Do we have less pages?
+        while (pages.size() < pageSizes.size())
+        {
+            std::vector<pdf::PDFObjectReference> references = pdf::PDFDocumentBuilder::createReferencesFromObjects(builder->copyFrom(pdf::PDFDocumentBuilder::createObjectsFromReferences({ pages.front() }), *builder->getStorage(), true));
+            Q_ASSERT(references.size() == 1);
+            pages.push_back(references.front());
+        }
+
+        Q_ASSERT(pages.size() == pageSizes.size());
+        for (size_t i = 0; i < pages.size(); ++i)
+        {
+            builder->setPageMediaBox(pages[i], QRectF(QPointF(0, 0), pageSizes[i]));
+        }
+
+        builder->setPages(std::move(pages));
+
+        if (modifier.finalize())
+        {
+            emit documentModified(PDFModifiedDocument(modifier.getDocument(), nullptr, modifier.getFlags()));
+        }
+    }
+}
+
 void PDFFormManager::clearEditors()
 {
     qDeleteAll(m_widgetEditors);

Pdf4QtLib/sources/pdfform.h

@@ -687,6 +687,11 @@ public:
                      QList<PDFRenderError>& errors,
                      QPainter* painter);
 
+    /// Performs paging, when XFA form needs to change page count and size.
+    /// If some change needs to be done, then signal \p documentModified
+    /// is emitted.
+    void performPaging();
+
     virtual int getInputPriority() const override { return FormPriority; }
 
 signals:

Pdf4QtLib/sources/pdfxfaengine.cpp

@@ -9679,8 +9679,11 @@ public:
 
     using LayoutItems = std::vector<LayoutItem>;
 
-    void setLayoutItems(PDFInteger pageIndex, LayoutItems layoutItems) { m_layout.layoutItems[pageIndex] = std::move(layoutItems); }
-    void setParagraphSettings(std::vector<xfa::XFA_ParagraphSettings> paragraphSettings) { m_layout.paragraphSettings = std::move(paragraphSettings); }
+    std::vector<QSizeF> getPageSizes() const { return m_layout.pageSizes; }
+
+    inline void setPageSizes(std::vector<QSizeF> pageSizes) { m_layout.pageSizes = std::move(pageSizes); }
+    inline void setLayoutItems(PDFInteger pageIndex, LayoutItems layoutItems) { m_layout.layoutItems[pageIndex] = std::move(layoutItems); }
+    inline void setParagraphSettings(std::vector<xfa::XFA_ParagraphSettings> paragraphSettings) { m_layout.paragraphSettings = std::move(paragraphSettings); }
 
     void draw(const QMatrix& pagePointToDevicePointMatrix,
               const PDFPage* page,
@@ -9691,6 +9694,7 @@ private:
 
     struct Layout
     {
+        std::vector<QSizeF> pageSizes;
         std::map<PDFInteger, LayoutItems> layoutItems;
         std::vector<xfa::XFA_ParagraphSettings> paragraphSettings;
     };
@@ -10648,6 +10652,7 @@ void PDFXFALayoutEngine::performLayout(PDFXFAEngineImpl* engine, const xfa::XFA_
 
     node->accept(this);
 
+    std::vector<QSizeF> pageSizes;
     std::map<PDFInteger, std::vector<Layout>> layoutPerPage;
 
     for (Layout& layout : m_layout)
@@ -10661,6 +10666,8 @@ void PDFXFALayoutEngine::performLayout(PDFXFAEngineImpl* engine, const xfa::XFA_
         layoutPerPage[layout.pageIndex].emplace_back(std::move(layout));
     }
 
+    pageSizes.reserve(layoutPerPage.size());
+
     PDFInteger pageIndex = 0;
     for (const auto& layoutSinglePage : layoutPerPage)
     {
@@ -10688,9 +10695,13 @@ void PDFXFALayoutEngine::performLayout(PDFXFAEngineImpl* engine, const xfa::XFA_
             }
         }
 
+        const PageInfo& pageInfo = m_pages.at(layoutSinglePage.first);
+        pageSizes.push_back(pageInfo.mediaBox.size());
+
         engine->setLayoutItems(pageIndex++, std::move(layoutItems));
     }
 
+    engine->setPageSizes(std::move(pageSizes));
     engine->setParagraphSettings(std::move(m_paragraphSettings));
 }
 
@@ -11364,6 +11375,11 @@ void PDFXFAEngine::setDocument(const PDFModifiedDocument& document, PDFForm* for
     m_impl->setDocument(document, form);
 }
 
+std::vector<QSizeF> PDFXFAEngine::getPageSizes() const
+{
+    return m_impl->getPageSizes();
+}
+
 void PDFXFAEngine::draw(const QMatrix& pagePointToDevicePointMatrix,
                         const PDFPage* page,
                         QList<PDFRenderError>& errors,
@@ -11381,6 +11397,13 @@ PDFXFAEngineImpl::PDFXFAEngineImpl() :
 
 void PDFXFAEngineImpl::setDocument(const PDFModifiedDocument& document, PDFForm* form)
 {
+    if (document.hasFlag(PDFModifiedDocument::XFA_Pagination))
+    {
+        // Do nothing - pagination of XFA was performed,
+        // nothing else has changed.
+        return;
+    }
+
     if (m_document != document || document.hasReset())
     {
         m_document = document;

Pdf4QtLib/sources/pdfxfaengine.h

@@ -38,6 +38,9 @@ public:
 
     void setDocument(const PDFModifiedDocument& document, PDFForm* form);
 
+    /// Returns list of page sizes (after paging is complete)
+    std::vector<QSizeF> getPageSizes() const;
+
     /// Draws XFA form
     /// \param pagePointToDevicePointMatrix Page point to device point matrix
     /// \param page Page

Pdf4QtViewer/pdfprogramcontroller.cpp

@@ -1562,6 +1562,11 @@ void PDFProgramController::onDocumentReadingFinished()
             pdf::PDFModifiedDocument document(m_pdfDocument.data(), m_optionalContentActivity);
             setDocument(document);
 
+            if (m_formManager)
+            {
+                m_formManager->performPaging();
+            }
+
             pdf::PDFDocumentRequirements requirements = pdf::PDFDocumentRequirements::parse(&m_pdfDocument->getStorage(), m_pdfDocument->getCatalog()->getRequirements());
             constexpr pdf::PDFDocumentRequirements::Requirements requirementFlags = pdf::PDFDocumentRequirements::Requirements(pdf::PDFDocumentRequirements::OCInteract |
                                                                                                                                pdf::PDFDocumentRequirements::OCAutoStates |