mirror of https://github.com/JakubMelka/PDF4QT.git
93 lines
2.3 KiB
C++
93 lines
2.3 KiB
C++
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// Copyright (C) 2020 Jakub Melka
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//
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// This file is part of PdfForQt.
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//
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// PdfForQt 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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// (at your option) any later version.
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//
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// PdfForQt 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 PDFForQt. If not, see <https://www.gnu.org/licenses/>.
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#include "pdfundoredomanager.h"
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namespace pdfviewer
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{
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PDFUndoRedoManager::PDFUndoRedoManager(QObject* parent) :
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BaseClass(parent)
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{
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}
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PDFUndoRedoManager::~PDFUndoRedoManager()
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{
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}
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void PDFUndoRedoManager::doUndo()
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{
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if (!canUndo())
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{
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// Undo operation can't be performed
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return;
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}
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UndoRedoItem item = m_undoSteps.back();
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m_undoSteps.pop_back();
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m_redoSteps.insert(m_redoSteps.begin(), item);
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clampUndoRedoSteps();
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emit undoRedoStateChanged();
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emit documentChangeRequest(item.document, item.flags);
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}
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void PDFUndoRedoManager::doRedo()
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{
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if (!canRedo())
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{
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// Redo operation can't be performed
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return;
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}
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UndoRedoItem item = m_redoSteps.front();
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m_redoSteps.erase(m_redoSteps.begin());
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m_undoSteps.push_back(item);
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clampUndoRedoSteps();
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emit undoRedoStateChanged();
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emit documentChangeRequest(item.document, item.flags);
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}
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void PDFUndoRedoManager::clear()
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{
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if (canUndo() || canRedo())
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{
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m_undoSteps.clear();
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m_redoSteps.clear();
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emit undoRedoStateChanged();
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}
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}
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void PDFUndoRedoManager::clampUndoRedoSteps()
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{
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if (m_undoSteps.size() > m_undoLimit)
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{
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// We erase from oldest steps to newest
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m_undoSteps.erase(m_undoSteps.begin(), std::next(m_undoSteps.begin(), m_undoSteps.size() - m_undoLimit));
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}
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if (m_redoSteps.size() > m_redoLimit)
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{
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// Newest steps are erased
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m_redoSteps.resize(m_redoLimit);
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}
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}
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} // namespace pdfviewer
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