1 files changed, 22 insertions, 17 deletions

diff --git a/src/widgets/widgets/qabstractscrollarea.cpp b/src/widgets/widgets/qabstractscrollarea.cpp
index 7fd94e6201..f6f8e8b795 100644
--- a/src/widgets/widgets/qabstractscrollarea.cpp
+++ b/src/widgets/widgets/qabstractscrollarea.cpp
@@ -295,22 +295,25 @@ void QAbstractScrollAreaPrivate::layoutChildren()
 void QAbstractScrollAreaPrivate::layoutChildren_helper(bool *needHorizontalScrollbar, bool *needVerticalScrollbar)
 {
     Q_Q(QAbstractScrollArea);
-    bool htransient = hbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, hbar);
+    QStyleOptionSlider barOpt;
+
+    hbar->initStyleOption(&barOpt);
+    bool htransient = hbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, &barOpt, hbar);
     bool needh = *needHorizontalScrollbar || ((hbarpolicy != Qt::ScrollBarAlwaysOff) && ((hbarpolicy == Qt::ScrollBarAlwaysOn && !htransient)
                             || ((hbarpolicy == Qt::ScrollBarAsNeeded || htransient)
                             && hbar->minimum() < hbar->maximum() && !hbar->sizeHint().isEmpty())));
+    const int hscrollOverlap = hbar->style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarOverlap, &barOpt, hbar);
 
-    bool vtransient = vbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, vbar);
+    vbar->initStyleOption(&barOpt);
+    bool vtransient = vbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, &barOpt, vbar);
     bool needv = *needVerticalScrollbar || ((vbarpolicy != Qt::ScrollBarAlwaysOff) && ((vbarpolicy == Qt::ScrollBarAlwaysOn && !vtransient)
                             || ((vbarpolicy == Qt::ScrollBarAsNeeded || vtransient)
                             && vbar->minimum() < vbar->maximum() && !vbar->sizeHint().isEmpty())));
+    const int vscrollOverlap = vbar->style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarOverlap, &barOpt, vbar);
 
     QStyleOption opt(0);
     opt.initFrom(q);
 
-    const int hscrollOverlap = hbar->style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarOverlap, &opt, hbar);
-    const int vscrollOverlap = vbar->style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarOverlap, &opt, vbar);
-
     const int hsbExt = hbar->sizeHint().height();
     const int vsbExt = vbar->sizeHint().width();
     const QPoint extPoint(vsbExt, hsbExt);
@@ -368,7 +371,7 @@ void QAbstractScrollAreaPrivate::layoutChildren_helper(bool *needHorizontalScrol
 #if QT_CONFIG(itemviews)
     if ((vscrollOverlap > 0 && needv) || (hscrollOverlap > 0 && needh)) {
         const QList<QHeaderView *> headers = q->findChildren<QHeaderView*>();
-        if (headers.count() <= 2) {
+        if (headers.size() <= 2) {
             for (const QHeaderView *header : headers) {
                 const QRect geo = header->geometry();
                 if (header->orientation() == Qt::Vertical && header->isVisible() && QStyle::visualRect(opt.direction, opt.rect, geo).left() <= opt.rect.width() / 2)
@@ -532,15 +535,13 @@ scrolling range.
 QSize QAbstractScrollArea::maximumViewportSize() const
 {
     Q_D(const QAbstractScrollArea);
-    int hsbExt = d->hbar->sizeHint().height();
-    int vsbExt = d->vbar->sizeHint().width();
-
     int f = 2 * d->frameWidth;
     QSize max = size() - QSize(f + d->left + d->right, f + d->top + d->bottom);
+    // Count the sizeHint of the bar only if it is displayed.
     if (d->vbarpolicy == Qt::ScrollBarAlwaysOn)
-        max.rwidth() -= vsbExt;
+        max.rwidth() -= d->vbar->sizeHint().width();
     if (d->hbarpolicy == Qt::ScrollBarAlwaysOn)
-        max.rheight() -= hsbExt;
+        max.rheight() -= d->hbar->sizeHint().height();
     return max;
 }
 
@@ -1099,7 +1100,7 @@ void QAbstractScrollArea::resizeEvent(QResizeEvent *)
     This event handler can be reimplemented in a subclass to receive
     paint events (passed in \a event), for the viewport() widget.
 
-    \note If you open a painter, make sure to open it on the viewport().
+    \note If you create a QPainter, it must operate on the viewport().
 
     \sa QWidget::paintEvent()
 */
@@ -1342,10 +1343,14 @@ bool QAbstractScrollAreaPrivate::canStartScrollingAt(const QPoint &startPos) con
 
 void QAbstractScrollAreaPrivate::flashScrollBars()
 {
-    bool htransient = hbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, hbar);
+    QStyleOptionSlider opt;
+    hbar->initStyleOption(&opt);
+
+    bool htransient = hbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, &opt, hbar);
     if ((hbarpolicy != Qt::ScrollBarAlwaysOff) && (hbarpolicy == Qt::ScrollBarAsNeeded || htransient))
         hbar->d_func()->flash();
-    bool vtransient = vbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, vbar);
+    vbar->initStyleOption(&opt);
+    bool vtransient = vbar->style()->styleHint(QStyle::SH_ScrollBar_Transient, &opt, vbar);
     if ((vbarpolicy != Qt::ScrollBarAlwaysOff) && (vbarpolicy == Qt::ScrollBarAsNeeded || vtransient))
         vbar->d_func()->flash();
 }
@@ -1426,9 +1431,9 @@ QSize QAbstractScrollArea::sizeHint() const
 
     if (!d->sizeHint.isValid() || d->sizeAdjustPolicy == QAbstractScrollArea::AdjustToContents) {
         const int f = 2 * d->frameWidth;
-        const QSize frame( f, f );
-        const bool vbarHidden = d->vbar->isHidden() || d->vbarpolicy == Qt::ScrollBarAlwaysOff;
-        const bool hbarHidden = d->hbar->isHidden() || d->hbarpolicy == Qt::ScrollBarAlwaysOff;
+        const QSize frame(f, f);
+        const bool vbarHidden = !d->vbar->isVisibleTo(this) || d->vbarpolicy == Qt::ScrollBarAlwaysOff;
+        const bool hbarHidden = !d->vbar->isVisibleTo(this) || d->hbarpolicy == Qt::ScrollBarAlwaysOff;
         const QSize scrollbars(vbarHidden ? 0 : d->vbar->sizeHint().width(),
                                hbarHidden ? 0 : d->hbar->sizeHint().height());
         d->sizeHint = frame + scrollbars + viewportSizeHint();