Actions/outline basics

PdfForQtLib/sources/pdfoutline.cpp

@@ -0,0 +1,110 @@
+//    Copyright (C) 2019 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt 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
+//    (at your option) any later version.
+//
+//    PdfForQt 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 PDFForQt.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "pdfoutline.h"
+#include "pdfdocument.h"
+#include "pdfexception.h"
+#include "pdfencoding.h"
+
+namespace pdf
+{
+
+QSharedPointer<PDFOutlineItem> PDFOutlineItem::parse(const PDFDocument* document, const PDFObject& root)
+{
+    const PDFObject& rootDereferenced = document->getObject(root);
+    if (rootDereferenced.isDictionary())
+    {
+        const PDFDictionary* dictionary = rootDereferenced.getDictionary();
+        const PDFObject& first = dictionary->get("First");
+
+        if (first.isReference())
+        {
+            QSharedPointer<PDFOutlineItem> result(new PDFOutlineItem());
+            std::set<PDFObjectReference> visitedOutlineItems;
+            parseImpl(document, result.get(), first.getReference(), visitedOutlineItems);
+            return result;
+        }
+    }
+
+    return QSharedPointer<PDFOutlineItem>();
+}
+
+void PDFOutlineItem::parseImpl(const PDFDocument* document,
+                               PDFOutlineItem* parent,
+                               PDFObjectReference currentItem,
+                               std::set<PDFObjectReference>& visitedOutlineItems)
+{
+    auto checkCyclicDependence = [&visitedOutlineItems](PDFObjectReference reference)
+    {
+        if (visitedOutlineItems.count(reference))
+        {
+            throw PDFException(PDFTranslationContext::tr("Outline items have cyclic dependence."));
+        }
+
+        visitedOutlineItems.insert(reference);
+    };
+    checkCyclicDependence(currentItem);
+
+    PDFObject dereferencedItem = document->getObjectByReference(currentItem);
+    while (dereferencedItem.isDictionary())
+    {
+        const PDFDictionary* dictionary = dereferencedItem.getDictionary();
+
+        QSharedPointer<PDFOutlineItem> currentOutlineItem(new PDFOutlineItem());
+        const PDFObject& titleObject = document->getObject(dictionary->get("Title"));
+        if (titleObject.isString())
+        {
+            currentOutlineItem->setTitle(PDFEncoding::convertTextString(titleObject.getString()));
+        }
+        currentOutlineItem->setAction(PDFAction::parse(document, dictionary->get("A")));
+
+        // Parse children of this item
+        const PDFObject& firstItem = dictionary->get("First");
+        if (firstItem.isReference())
+        {
+            parseImpl(document, currentOutlineItem.get(), firstItem.getReference(), visitedOutlineItems);
+        }
+
+        // Add new child to the parent
+        parent->addChild(qMove(currentOutlineItem));
+
+        // Parse next item
+        const PDFObject& nextItem = dictionary->get("Next");
+        if (nextItem.isReference())
+        {
+            checkCyclicDependence(nextItem.getReference());
+            dereferencedItem = document->getObject(nextItem);
+        }
+        else
+        {
+            // We are finished
+            break;
+        }
+    }
+}
+
+const PDFAction* PDFOutlineItem::getAction() const
+{
+    return m_action.get();
+}
+
+void PDFOutlineItem::setAction(const PDFActionPtr& action)
+{
+    m_action = action;
+}
+
+}   // namespace pdf