Brush up the taskmenuextension example

When porting the code to Python, some issues showed up.

- Rewrite cellRect() to take the position (reason being
  that porting the existing code to Python creates
  problems with implicit conversion to float in the division).
- Use plain assignment by operator[] to replace the characters
  in the string
- Avoid repeating return types.
- Streamline code.
- Initialize myState member variable.
- Indicate C++ in the tool tip

Task-number: PYSIDE-1455
Change-Id: I62fa61eebaa2eefe8db0842d6a3789bd7cd4257e
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

4 files changed, 31 insertions, 33 deletions

diff --git a/examples/designer/taskmenuextension/tictactoe.cpp b/examples/designer/taskmenuextension/tictactoe.cpp
index c6370a2cb..f96c5af2b 100644
--- a/examples/designer/taskmenuextension/tictactoe.cpp
+++ b/examples/designer/taskmenuextension/tictactoe.cpp
@@ -56,32 +56,31 @@
 static inline QString defaultState() { return QStringLiteral("---------"); }
 
 TicTacToe::TicTacToe(QWidget *parent)
-    : QWidget(parent)
+    : QWidget(parent), myState(defaultState())
 {
 }
 
 QSize TicTacToe::minimumSizeHint() const
 {
-    return QSize(200, 200);
+    return {200, 200};
 }
 
 QSize TicTacToe::sizeHint() const
 {
-    return QSize(200, 200);
+    return {200, 200};
 }
 
 void TicTacToe::setState(const QString &newState)
 {
     turnNumber = 0;
     myState = defaultState();
-    int position = 0;
-    while (position < 9 && position < newState.length()) {
-        QChar mark = newState.at(position);
+    const int count = qMin(9, int(newState.length()));
+    for (int position = 0; position < count; ++position) {
+        const QChar mark = newState.at(position);
         if (mark == Cross || mark == Nought) {
             ++turnNumber;
-            myState.replace(position, 1, mark);
+            myState[position] = mark;
         }
-        position++;
     }
     update();
 }
@@ -102,19 +101,16 @@ void TicTacToe::mousePressEvent(QMouseEvent *event)
 {
     if (turnNumber == 9) {
         clearBoard();
-        update();
-    } else {
-        for (int position = 0; position < 9; ++position) {
-            QRect cell = cellRect(position / 3, position % 3);
-            if (cell.contains(event->pos())) {
-                if (myState.at(position) == Empty) {
-                    if (turnNumber % 2 == 0)
-                        myState.replace(position, 1, Cross);
-                    else
-                        myState.replace(position, 1, Nought);
-                    ++turnNumber;
-                    update();
-                }
+        return;
+    }
+    for (int position = 0; position < 9; ++position) {
+        const QRect &cell = cellRect(position);
+        if (cell.contains(event->position().toPoint())) {
+            if (myState.at(position) == Empty) {
+                myState[position] = turnNumber % 2 == 0
+                                    ? Cross : Nought;
+                ++turnNumber;
+                update();
             }
         }
     }
@@ -134,7 +130,7 @@ void TicTacToe::paintEvent(QPaintEvent * /* event */)
     painter.setPen(QPen(Qt::darkBlue, 2));
 
     for (int position = 0; position < 9; ++position) {
-        QRect cell = cellRect(position / 3, position % 3);
+        const QRect &cell = cellRect(position);
 
         if (myState.at(position) == Cross) {
             painter.drawLine(cell.topLeft(), cell.bottomRight());
@@ -150,7 +146,7 @@ void TicTacToe::paintEvent(QPaintEvent * /* event */)
         if (myState.at(position) != Empty
                 && myState.at(position + 1) == myState.at(position)
                 && myState.at(position + 2) == myState.at(position)) {
-            int y = cellRect((position / 3), 0).center().y();
+            const int y = cellRect(position).center().y();
             painter.drawLine(0, y, width(), y);
             turnNumber = 9;
         }
@@ -160,7 +156,7 @@ void TicTacToe::paintEvent(QPaintEvent * /* event */)
         if (myState.at(position) != Empty
                 && myState.at(position + 3) == myState.at(position)
                 && myState.at(position + 6) == myState.at(position)) {
-            int x = cellRect(0, position).center().x();
+            const int x = cellRect(position).center().x();
             painter.drawLine(x, 0, x, height());
             turnNumber = 9;
         }
@@ -177,12 +173,15 @@ void TicTacToe::paintEvent(QPaintEvent * /* event */)
     }
 }
 
-QRect TicTacToe::cellRect(int row, int column) const
+QRect TicTacToe::cellRect(int position) const
 {
     const int HMargin = width() / 30;
     const int VMargin = height() / 30;
-    return QRect(column * cellWidth() + HMargin,
-                 row * cellHeight() + VMargin,
-                 cellWidth() - 2 * HMargin,
-                 cellHeight() - 2 * VMargin);
+    const int row = position / 3;
+    const int column = position % 3;
+    const QPoint pos{column * cellWidth() + HMargin,
+                     row * cellHeight() + VMargin};
+    const QSize size{cellWidth() - 2 * HMargin,
+                     cellHeight() - 2 * VMargin};
+    return {pos, size};
 }
diff --git a/examples/designer/taskmenuextension/tictactoe.h b/examples/designer/taskmenuextension/tictactoe.h
index 23784d750..5f081bbdc 100644
--- a/examples/designer/taskmenuextension/tictactoe.h
+++ b/examples/designer/taskmenuextension/tictactoe.h
@@ -82,7 +82,7 @@ private:
     static constexpr char16_t Cross = 'X';
     static constexpr char16_t Nought = 'O';
 
-    QRect cellRect(int row, int col) const;
+    QRect cellRect(int position) const;
     int cellWidth() const { return width() / 3; }
     int cellHeight() const { return height() / 3; }
 
diff --git a/examples/designer/taskmenuextension/tictactoedialog.cpp b/examples/designer/taskmenuextension/tictactoedialog.cpp
index 8b62064f8..a13b093d2 100644
--- a/examples/designer/taskmenuextension/tictactoedialog.cpp
+++ b/examples/designer/taskmenuextension/tictactoedialog.cpp
@@ -74,11 +74,10 @@ TicTacToeDialog::TicTacToeDialog(TicTacToe *tic, QWidget *parent)
     connect(buttonBox, &QDialogButtonBox::accepted, this, &TicTacToeDialog::saveState);
     connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
 
-    QVBoxLayout *mainLayout = new QVBoxLayout;
+    QVBoxLayout *mainLayout = new QVBoxLayout(this);
     mainLayout->addWidget(editor);
     mainLayout->addWidget(buttonBox);
 
-    setLayout(mainLayout);
     setWindowTitle(tr("Edit State"));
 }
 //! [0]
diff --git a/examples/designer/taskmenuextension/tictactoeplugin.cpp b/examples/designer/taskmenuextension/tictactoeplugin.cpp
index 45075fe62..5515526bc 100644
--- a/examples/designer/taskmenuextension/tictactoeplugin.cpp
+++ b/examples/designer/taskmenuextension/tictactoeplugin.cpp
@@ -74,7 +74,7 @@ QString TicTacToePlugin::group() const
 
 QString TicTacToePlugin::toolTip() const
 {
-    return QString();
+    return QStringLiteral("Tic Tac Toe Example, demonstrating class QDesignerTaskMenuExtension (C++)");
 }
 
 QString TicTacToePlugin::whatsThis() const