Accessibility: Fix rect for QComboBox and QRadioButton

This is especially relevant on mobile devices where screen readers often
send mouse clicks to the middle of the object.

Task-number: QTBUG-39100
Change-Id: I5972f21dd12434601d86136215ab9b61248c9691
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>

src/widgets/accessible/simplewidgets.cpp

@@ -158,6 +158,26 @@ QAccessible::State QAccessibleButton::state() const
     return state;
 }
 
+QRect QAccessibleButton::rect() const
+{
+    QAbstractButton *ab = button();
+    if (!ab->isVisible())
+        return QRect();
+
+    if (QCheckBox *cb = qobject_cast<QCheckBox *>(ab)) {
+        QPoint wpos = cb->mapToGlobal(QPoint(0, 0));
+        QStyleOptionButton opt;
+        cb->initStyleOption(&opt);
+        return cb->style()->subElementRect(QStyle::SE_CheckBoxClickRect, &opt, cb).translated(wpos);
+    } else if (QRadioButton *rb = qobject_cast<QRadioButton *>(ab)) {
+        QPoint wpos = rb->mapToGlobal(QPoint(0, 0));
+        QStyleOptionButton opt;
+        rb->initStyleOption(&opt);
+        return rb->style()->subElementRect(QStyle::SE_RadioButtonClickRect, &opt, rb).translated(wpos);
+    }
+    return QAccessibleWidget::rect();
+}
+
 QStringList QAccessibleButton::actionNames() const
 {
     QStringList names;

src/widgets/accessible/simplewidgets.h

@@ -63,6 +63,7 @@ public:
 
     QString text(QAccessible::Text t) const Q_DECL_OVERRIDE;
     QAccessible::State state() const Q_DECL_OVERRIDE;
+    QRect rect() const Q_DECL_OVERRIDE;
 
     QStringList actionNames() const Q_DECL_OVERRIDE;
     void doAction(const QString &actionName) Q_DECL_OVERRIDE;

src/widgets/widgets/qcheckbox.h

@@ -86,6 +86,7 @@ protected:
 private:
     Q_DECLARE_PRIVATE(QCheckBox)
     Q_DISABLE_COPY(QCheckBox)
+    friend class QAccessibleButton;
 };
 
 QT_END_NAMESPACE

src/widgets/widgets/qradiobutton.h

@@ -73,6 +73,7 @@ protected:
 private:
     Q_DECLARE_PRIVATE(QRadioButton)
     Q_DISABLE_COPY(QRadioButton)
+    friend class QAccessibleButton;
 };
 
 QT_END_NAMESPACE