mirror of https://github.com/JakubMelka/PDF4QT.git
98 lines
3.8 KiB
C++
98 lines
3.8 KiB
C++
// Copyright (C) 2020 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/>.
|
|
|
|
#ifndef PDFOPTIMIZER_H
|
|
#define PDFOPTIMIZER_H
|
|
|
|
#include "pdfdocument.h"
|
|
|
|
#include <QObject>
|
|
|
|
namespace pdf
|
|
{
|
|
|
|
/// Class for optimalizing documents. Can examine object structure and it's dependencies,
|
|
/// and remove unused objects, merge same objects, or even recompress some streams
|
|
/// to achieve better optimization ratio. Optimization is configurable, user can specify,
|
|
/// which optimization steps should be done and which not.
|
|
class PDFFORQTLIBSHARED_EXPORT PDFOptimizer : public QObject
|
|
{
|
|
Q_OBJECT
|
|
|
|
public:
|
|
|
|
enum OptimizationFlag
|
|
{
|
|
None = 0x0000, ///< No optimization is performed
|
|
DereferenceSimpleObjects = 0x0001, ///< If simple objects are referenced (such as integers, bools, etc.), then they are dereferenced
|
|
RemoveNullObjects = 0x0002, ///< Remove null objects from dictionary entries
|
|
RemoveUnusedObjects = 0x0004, ///< Remove not referenced objects
|
|
MergeIdenticalObjects = 0x0008, ///< Merge identical objects
|
|
ShrinkObjectStorage = 0x0010, ///< Shrink object storage, so unused objects are filled with used (and generation number increased)
|
|
RecompressFlateStreams = 0x0020, ///< Flate streams are recompressed with maximal compression
|
|
All = 0xFFFF, ///< All optimizations turned on
|
|
};
|
|
Q_DECLARE_FLAGS(OptimizationFlags, OptimizationFlag)
|
|
|
|
explicit PDFOptimizer(OptimizationFlags flags, QObject* parent);
|
|
|
|
/// Set document, which should be optimalized
|
|
/// \param document Document to optimalize
|
|
void setDocument(const PDFDocument* document) { setStorage(document->getStorage()); }
|
|
|
|
/// Set storage directly (storage must be valid and filled with objects)
|
|
/// \param storage Storage
|
|
void setStorage(const PDFObjectStorage& storage) { m_storage = storage; }
|
|
|
|
/// Perform document optimalization. During optimization process, various
|
|
/// signals are emitted to view progress.
|
|
void optimize();
|
|
|
|
/// Returns object storage used for optimization
|
|
const PDFObjectStorage& getStorage() const { return m_storage; }
|
|
|
|
/// Returns object storage by move semantics, old object storage is destroyed
|
|
PDFObjectStorage takeStorage() { return qMove(m_storage); }
|
|
|
|
/// Returns optimized document. Object storage is cleared after
|
|
/// this function call.
|
|
PDFDocument takeOptimizedDocument() { return PDFDocument(qMove(m_storage), PDFVersion(2, 0)); }
|
|
|
|
OptimizationFlags getFlags() const;
|
|
void setFlags(OptimizationFlags flags);
|
|
|
|
signals:
|
|
void optimizationStarted();
|
|
void optimizationProgress(QString progressText);
|
|
void optimizationFinished();
|
|
|
|
private:
|
|
bool performDereferenceSimpleObjects();
|
|
bool performRemoveNullObjects();
|
|
bool performRemoveUnusedObjects();
|
|
bool performMergeIdenticalObjects();
|
|
bool performShrinkObjectStorage();
|
|
bool performRecompressFlateStreams();
|
|
|
|
OptimizationFlags m_flags;
|
|
PDFObjectStorage m_storage;
|
|
};
|
|
|
|
} // namespace pdf
|
|
|
|
#endif // PDFOPTIMIZER_H
|