mirror of
https://github.com/JakubMelka/PDF4QT.git
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105 lines
3.4 KiB
C++
105 lines
3.4 KiB
C++
// Copyright (C) 2020-2021 Jakub Melka
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//
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// This file is part of PDF4QT.
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//
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// PDF4QT is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// with the written consent of the copyright owner, any later version.
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//
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// PDF4QT is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
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#ifndef PDFUNDOREDOMANAGER_H
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#define PDFUNDOREDOMANAGER_H
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#include "pdfdocument.h"
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#include <QObject>
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namespace pdfviewer
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{
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/// Undo/Redo document manager, it is managing undo and redo steps,
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/// when document is modified.
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class PDFUndoRedoManager : public QObject
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{
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Q_OBJECT
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private:
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using BaseClass = QObject;
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public:
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explicit PDFUndoRedoManager(QObject* parent);
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virtual ~PDFUndoRedoManager() override;
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bool canUndo() const { return !m_undoSteps.empty(); }
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bool canRedo() const { return !m_redoSteps.empty(); }
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/// Performs single undo step. If Undo action can't be performed,
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/// then nothing happens.
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void doUndo();
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/// Performs single redo step. If Redo action can't be performed,
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/// then nothing happens.
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void doRedo();
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/// Clears all undo/redo steps
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void clear();
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/// Create undo action (after document modification)
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/// \param document Document created by modification
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/// \param oldDocument Old document
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void createUndo(pdf::PDFModifiedDocument document, pdf::PDFDocumentPointer oldDocument);
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/// Sets maximum steps for undo/redo
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/// \param undoLimit Maximum undo steps
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/// \param redoLimit Maximum redo steps
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void setMaximumSteps(size_t undoLimit, size_t redoLimit);
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signals:
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/// This signals are emitted, when undo/redo action availability has
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/// been changed (for example, user pressed undo/redo action)
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void undoRedoStateChanged();
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/// This signal is being emitted, when user performs undo/redo action.
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/// Before signal is emitted, this object is in corrected state, as action
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/// is performed.
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/// \param document Document
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void documentChangeRequest(pdf::PDFModifiedDocument document);
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private:
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/// Clamps undo/redo steps so they fit the limits
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void clampUndoRedoSteps();
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struct UndoRedoItem
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{
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explicit inline UndoRedoItem() = default;
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explicit inline UndoRedoItem(pdf::PDFDocumentPointer oldDocument, pdf::PDFDocumentPointer newDocument, pdf::PDFModifiedDocument::ModificationFlags flags) :
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oldDocument(qMove(oldDocument)),
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newDocument(qMove(newDocument)),
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flags(flags)
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{
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}
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pdf::PDFDocumentPointer oldDocument;
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pdf::PDFDocumentPointer newDocument;
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pdf::PDFModifiedDocument::ModificationFlags flags = pdf::PDFModifiedDocument::None;
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};
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size_t m_undoLimit = 0;
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size_t m_redoLimit = 0;
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std::vector<UndoRedoItem> m_undoSteps;
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std::vector<UndoRedoItem> m_redoSteps;
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};
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} // namespace pdfviewer
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#endif // PDFUNDOREDOMANAGER_H
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