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++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include <QUndoCommand>
++
++ //! [0]
++ class AppendText : public QUndoCommand
++ {
++ public:
++ AppendText(QString *doc, const QString &text)
++ : m_document(doc), m_text(text) { setText("append text"); }
++ void undo() override
++ { m_document->chop(m_text.length()); }
++ void redo() override
++ { m_document->append(m_text); }
++ bool mergeWith(const QUndoCommand *other) override;
++ private:
++ QString *m_document;
++ QString m_text;
++ };
++ //! [0]
++
++ struct MyCommand : public QUndoCommand
++ {
++ MyCommand() { setText("My Command"); }
++ void undo() override {}
++ void redo() override {}
++ int id() const override { return 123; } // unique id for this command
++ };
++
++ struct InsertText : public QUndoCommand
++ {
++ InsertText(QString *doc, int idx, const QString &text, QUndoCommand *parent = nullptr);
++ };
++
++ struct SetColor : public QUndoCommand
++ {
++ SetColor(QString *doc, int idx, int len, const Qt::GlobalColor &color, QUndoCommand *parent = nullptr);
++ };
++
++ void examples(QUndoStack *stack, QString *document, int idx, const QString &text)
++ {
++ {
++ //! [1]
++ MyCommand *command1 = new MyCommand();
++ stack->push(command1);
++ MyCommand *command2 = new MyCommand();
++ stack->push(command2);
++
++ stack->undo();
++
++ MyCommand *command3 = new MyCommand();
++ stack->push(command3); // command2 gets deleted
++ //! [1]
++ }
++
++ {
++ QUndoStack stack;
++
++ //! [2]
++ QUndoCommand *insertRed = new QUndoCommand(); // an empty command
++ insertRed->setText("insert red text");
++
++ new InsertText(document, idx, text, insertRed); // becomes child of insertRed
++ new SetColor(document, idx, text.length(), Qt::red, insertRed);
++
++ stack.push(insertRed);
++ //! [2]
++ }
++ }
++
++ //! [3]
++ bool AppendText::mergeWith(const QUndoCommand *other)
++ {
++ if (other->id() != id()) // make sure other is also an AppendText command
++ return false;
++ m_text += static_cast<const AppendText*>(other)->m_text;
++ return true;
++ }
++ //! [3]
++
++ void wrap( QUndoStack &stack, QString *document, int idx, const QString &text)
++ {
++ //! [4]
++ stack.beginMacro("insert red text");
++ stack.push(new InsertText(document, idx, text));
++ stack.push(new SetColor(document, idx, text.length(), Qt::red));
++ stack.endMacro(); // indexChanged() is emitted
++ //! [4]
++
++
++ //! [5]
++ QUndoCommand *insertRed = new QUndoCommand(); // an empty command
++ insertRed->setText("insert red text");
++
++ new InsertText(document, idx, text, insertRed); // becomes child of insertRed
++ new SetColor(document, idx, text.length(), Qt::red, insertRed);
++
++ stack.push(insertRed);
++ //! [5]
++ }