Make initStyleOption virtual for various classes

Often a simple change in the styleoptions is needed in e.g a paintEvent,
but it was impossible without copying the whole paint-function which
is not always trivial and also wouldn't be kept up-to-date if it was
changed in Qt.
The initStyleOption is similar to viewOptions in QAbstractTableView
and it is handy that this function is virtual. Furthermore
QStyledItemDelegate::initStyleOption is already virtual.

This change only makes initStyleOption virtual for public classes.

[ChangeLog][QtWidgets] InitStyleOption has been made virtual in
public Qt classes to make override of stylebehavior more simple.

Change-Id: I38974c6d4dd0793ca5976ecf3aa28892215a1579
Task-number: QTBUG-77642
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>

src/widgets/itemviews/qheaderview.cpp

@@ -3385,6 +3385,14 @@ void QHeaderView::initStyleOption(QStyleOptionHeader *option) const
     option->section = 0;
 }
 
+void QHeaderView::initStyleOption(QStyleOptionFrame *option) const
+{
+    // The QFrame version is only here to avoid compiler warnings.
+    // If invoked (it can be invoked with QFrame *f = headerview; f->initStyleOption()),
+    // and here we just pass it on to the frame version.
+    QFrame::initStyleOption(option);
+}
+
 bool QHeaderViewPrivate::isSectionSelected(int section) const
 {
     int i = section * 2;

src/widgets/itemviews/qheaderview.h

@@ -230,12 +230,14 @@ protected:
     QModelIndex moveCursor(CursorAction, Qt::KeyboardModifiers) override;
     void setSelection(const QRect& rect, QItemSelectionModel::SelectionFlags flags) override;
     QRegion visualRegionForSelection(const QItemSelection &selection) const override;
-    void initStyleOption(QStyleOptionHeader *option) const;
+    virtual void initStyleOption(QStyleOptionHeader *option) const;
 
     friend class QTableView;
     friend class QTreeView;
 
 private:
+    void initStyleOption(QStyleOptionFrame *option) const override;
+
     // ### Qt6: make them protected slots in QHeaderViewPrivate
     Q_PRIVATE_SLOT(d_func(), void _q_sectionsRemoved(const QModelIndex &parent, int logicalFirst, int logicalLast))
     Q_PRIVATE_SLOT(d_func(), void _q_sectionsAboutToBeMoved(const QModelIndex &sourceParent, int logicalStart, int logicalEnd, const QModelIndex &destinationParent, int logicalDestination))

src/widgets/widgets/qabstractspinbox.cpp

@@ -1629,6 +1629,8 @@ void QAbstractSpinBoxPrivate::init()
     edit->setValidator(validator);
 
     QStyleOptionSpinBox opt;
+    // ### This is called from the ctor and thus we shouldn't call initStyleOption yet
+    // ### as we only call the base class implementation of initStyleOption called.
     q->initStyleOption(&opt);
     spinClickTimerInterval = q->style()->styleHint(QStyle::SH_SpinBox_ClickAutoRepeatRate, &opt, q);
     spinClickThresholdTimerInterval = q->style()->styleHint(QStyle::SH_SpinBox_ClickAutoRepeatThreshold, &opt, q);

src/widgets/widgets/qabstractspinbox.h

@@ -160,7 +160,7 @@ protected:
     void timerEvent(QTimerEvent *event) override;
     void paintEvent(QPaintEvent *event) override;
     void showEvent(QShowEvent *event) override;
-    void initStyleOption(QStyleOptionSpinBox *option) const;
+    virtual void initStyleOption(QStyleOptionSpinBox *option) const;
 
     QLineEdit *lineEdit() const;
     void setLineEdit(QLineEdit *edit);

src/widgets/widgets/qcheckbox.h

@@ -81,7 +81,7 @@ protected:
     void nextCheckState() override;
     void paintEvent(QPaintEvent *) override;
     void mouseMoveEvent(QMouseEvent *) override;
-    void initStyleOption(QStyleOptionButton *option) const;
+    virtual void initStyleOption(QStyleOptionButton *option) const;
 
 
 private:

src/widgets/widgets/qcombobox.h

@@ -230,7 +230,7 @@ protected:
     void contextMenuEvent(QContextMenuEvent *e) override;
 #endif // QT_NO_CONTEXTMENU
     void inputMethodEvent(QInputMethodEvent *) override;
-    void initStyleOption(QStyleOptionComboBox *option) const;
+    virtual void initStyleOption(QStyleOptionComboBox *option) const;
 
 
 protected:

src/widgets/widgets/qdatetimeedit.h

@@ -193,7 +193,7 @@ protected:
     StepEnabled stepEnabled() const override;
     void mousePressEvent(QMouseEvent *event) override;
     void paintEvent(QPaintEvent *event) override;
-    void initStyleOption(QStyleOptionSpinBox *option) const;
+    void initStyleOption(QStyleOptionSpinBox *option) const override;
 
     QDateTimeEdit(const QVariant &val, QMetaType::Type parserType, QWidget *parent = nullptr);
 private:

src/widgets/widgets/qdial.h

@@ -90,7 +90,7 @@ protected:
     void mouseMoveEvent(QMouseEvent *me) override;
 
     void sliderChange(SliderChange change) override;
-    void initStyleOption(QStyleOptionSlider *option) const;
+    virtual void initStyleOption(QStyleOptionSlider *option) const;
 
 
 private:

src/widgets/widgets/qdockwidget.h

@@ -116,7 +116,7 @@ protected:
     void closeEvent(QCloseEvent *event) override;
     void paintEvent(QPaintEvent *event) override;
     bool event(QEvent *event) override;
-    void initStyleOption(QStyleOptionDockWidget *option) const;
+    virtual void initStyleOption(QStyleOptionDockWidget *option) const;
 
 private:
     Q_DECLARE_PRIVATE(QDockWidget)

src/widgets/widgets/qfocusframe.h

@@ -64,7 +64,7 @@ protected:
 
     bool eventFilter(QObject *, QEvent *) override;
     void paintEvent(QPaintEvent *) override;
-    void initStyleOption(QStyleOption *option) const;
+    virtual void initStyleOption(QStyleOption *option) const;
 
 private:
     Q_DECLARE_PRIVATE(QFocusFrame)

src/widgets/widgets/qframe.h

@@ -116,7 +116,7 @@ protected:
 
 protected:
     QFrame(QFramePrivate &dd, QWidget* parent = nullptr, Qt::WindowFlags f = Qt::WindowFlags());
-    void initStyleOption(QStyleOptionFrame *option) const;
+    virtual void initStyleOption(QStyleOptionFrame *option) const;
 
 private:
     Q_DISABLE_COPY(QFrame)

src/widgets/widgets/qgroupbox.h

@@ -94,7 +94,7 @@ protected:
     void mousePressEvent(QMouseEvent *event) override;
     void mouseMoveEvent(QMouseEvent *event) override;
     void mouseReleaseEvent(QMouseEvent *event) override;
-    void initStyleOption(QStyleOptionGroupBox *option) const;
+    virtual void initStyleOption(QStyleOptionGroupBox *option) const;
 
 
 private:

src/widgets/widgets/qlineedit.h

@@ -229,7 +229,7 @@ protected:
 #endif
 
     void inputMethodEvent(QInputMethodEvent *) override;
-    void initStyleOption(QStyleOptionFrame *option) const;
+    virtual void initStyleOption(QStyleOptionFrame *option) const;
 public:
     QVariant inputMethodQuery(Qt::InputMethodQuery) const override;
     Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery property, QVariant argument) const;

src/widgets/widgets/qmenu.h

@@ -257,7 +257,7 @@ protected:
     void timerEvent(QTimerEvent *) override;
     bool event(QEvent *) override;
     bool focusNextPrevChild(bool next) override;
-    void initStyleOption(QStyleOptionMenuItem *option, const QAction *action) const;
+    virtual void initStyleOption(QStyleOptionMenuItem *option, const QAction *action) const;
 
 private Q_SLOTS:
     void internalDelayedPopup();

src/widgets/widgets/qmenubar.h

@@ -150,7 +150,7 @@ protected:
     void timerEvent(QTimerEvent *) override;
     bool eventFilter(QObject *, QEvent *) override;
     bool event(QEvent *) override;
-    void initStyleOption(QStyleOptionMenuItem *option, const QAction *action) const;
+    virtual void initStyleOption(QStyleOptionMenuItem *option, const QAction *action) const;
 
 private:
     Q_DECLARE_PRIVATE(QMenuBar)

src/widgets/widgets/qprogressbar.cpp

@@ -107,6 +107,8 @@ void QProgressBarPrivate::resetLayoutItemMargins()
 {
     Q_Q(QProgressBar);
     QStyleOptionProgressBar option;
+    // ### It seems like this can be called directly from the constructor which should be avoided
+    // ### if possible, since we will not call a possible re-implemented version
     q->initStyleOption(&option);
     setLayoutItemMargins(QStyle::SE_ProgressBarLayoutItem, &option);
 }

src/widgets/widgets/qprogressbar.h

@@ -111,7 +111,7 @@ Q_SIGNALS:
 protected:
     bool event(QEvent *e) override;
     void paintEvent(QPaintEvent *) override;
-    void initStyleOption(QStyleOptionProgressBar *option) const;
+    virtual void initStyleOption(QStyleOptionProgressBar *option) const;
 
 private:
     Q_DECLARE_PRIVATE(QProgressBar)

src/widgets/widgets/qpushbutton.h

@@ -93,7 +93,7 @@ protected:
     void keyPressEvent(QKeyEvent *) override;
     void focusInEvent(QFocusEvent *) override;
     void focusOutEvent(QFocusEvent *) override;
-    void initStyleOption(QStyleOptionButton *option) const;
+    virtual void initStyleOption(QStyleOptionButton *option) const;
     bool hitButton(const QPoint &pos) const override;
     QPushButton(QPushButtonPrivate &dd, QWidget* parent = nullptr);
 

src/widgets/widgets/qradiobutton.h

@@ -68,7 +68,7 @@ protected:
     bool hitButton(const QPoint &) const override;
     void paintEvent(QPaintEvent *) override;
     void mouseMoveEvent(QMouseEvent *) override;
-    void initStyleOption(QStyleOptionButton *button) const;
+    virtual void initStyleOption(QStyleOptionButton *button) const;
 
 
 private:

src/widgets/widgets/qrubberband.h

@@ -79,7 +79,7 @@ protected:
     void showEvent(QShowEvent *) override;
     void resizeEvent(QResizeEvent *) override;
     void moveEvent(QMoveEvent *) override;
-    void initStyleOption(QStyleOptionRubberBand *option) const;
+    virtual void initStyleOption(QStyleOptionRubberBand *option) const;
 
 private:
     Q_DECLARE_PRIVATE(QRubberBand)

src/widgets/widgets/qscrollbar.h

@@ -76,7 +76,7 @@ protected:
 #ifndef QT_NO_CONTEXTMENU
     void contextMenuEvent(QContextMenuEvent *) override;
 #endif
-    void initStyleOption(QStyleOptionSlider *option) const;
+    virtual void initStyleOption(QStyleOptionSlider *option) const;
 
 
 private:

src/widgets/widgets/qslider.cpp

@@ -91,6 +91,8 @@ void QSliderPrivate::resetLayoutItemMargins()
 {
     Q_Q(QSlider);
     QStyleOptionSlider opt;
+    // ### This is (also) reached from the ctor which is unfortunate since a possible
+    // ### re-implementation of initStyleOption is then not called.
     q->initStyleOption(&opt);
     setLayoutItemMargins(QStyle::SE_SliderLayoutItem, &opt);
 }

src/widgets/widgets/qslider.h

@@ -89,7 +89,7 @@ protected:
     void mousePressEvent(QMouseEvent *ev) override;
     void mouseReleaseEvent(QMouseEvent *ev) override;
     void mouseMoveEvent(QMouseEvent *ev) override;
-    void initStyleOption(QStyleOptionSlider *option) const;
+    virtual void initStyleOption(QStyleOptionSlider *option) const;
 
 
 private:

src/widgets/widgets/qtabbar.h

@@ -212,7 +212,7 @@ protected:
     void keyPressEvent(QKeyEvent *) override;
     void changeEvent(QEvent *) override;
     void timerEvent(QTimerEvent *event) override;
-    void initStyleOption(QStyleOptionTab *option, int tabIndex) const;
+    virtual void initStyleOption(QStyleOptionTab *option, int tabIndex) const;
 
 #ifndef QT_NO_ACCESSIBILITY
     friend class QAccessibleTabBar;

src/widgets/widgets/qtabwidget.h

@@ -171,7 +171,7 @@ protected:
     void setTabBar(QTabBar *);
     void changeEvent(QEvent *) override;
     bool event(QEvent *) override;
-    void initStyleOption(QStyleOptionTabWidgetFrame *option) const;
+    virtual void initStyleOption(QStyleOptionTabWidgetFrame *option) const;
 
 
 private:

src/widgets/widgets/qtoolbar.h

@@ -181,7 +181,7 @@ protected:
     void changeEvent(QEvent *event) override;
     void paintEvent(QPaintEvent *event) override;
     bool event(QEvent *event) override;
-    void initStyleOption(QStyleOptionToolBar *option) const;
+    virtual void initStyleOption(QStyleOptionToolBar *option) const;
 
 
 private:

src/widgets/widgets/qtoolbutton.h

@@ -119,7 +119,7 @@ protected:
 
     bool hitButton(const QPoint &pos) const override;
     void nextCheckState() override;
-    void initStyleOption(QStyleOptionToolButton *option) const;
+    virtual void initStyleOption(QStyleOptionToolButton *option) const;
 
 private:
     Q_DISABLE_COPY(QToolButton)