Long live Qt!

1 files changed, 69 insertions, 0 deletions

diff --git a/doc/src/snippets/code/src_gui_util_qundostack.cpp b/doc/src/snippets/code/src_gui_util_qundostack.cpp
new file mode 100644
index 0000000..3949e1e
--- /dev/null
+++ b/doc/src/snippets/code/src_gui_util_qundostack.cpp
@@ -0,0 +1,69 @@
+//! [0]
+class AppendText : public QUndoCommand
+{
+public:
+    AppendText(QString *doc, const QString &text)
+        : m_document(doc), m_text(text) { setText("append text"); }
+    virtual void undo()
+        { m_document->chop(m_text.length()); }
+    virtual void redo()
+        { m_document->append(m_text); }
+private:
+    QString *m_document;
+    QString m_text;
+};
+//! [0]
+
+
+//! [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]
+
+
+//! [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]
+
+
+//! [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]