1 files changed, 95 insertions, 1 deletions

diff --git a/src/widgets/itemviews/qheaderview.cpp b/src/widgets/itemviews/qheaderview.cpp
index edfbc5c8f1..c9a845fc7b 100644
--- a/src/widgets/itemviews/qheaderview.cpp
+++ b/src/widgets/itemviews/qheaderview.cpp
@@ -550,6 +550,22 @@ QSize QHeaderView::sizeHint() const
 }
 
 /*!
+    \reimp
+*/
+
+void QHeaderView::setVisible(bool v)
+{
+    bool actualChange = (v != isVisible());
+    QAbstractItemView::setVisible(v);
+    if (actualChange) {
+        QAbstractScrollArea *parent = qobject_cast<QAbstractScrollArea*>(parentWidget());
+        if (parent)
+            parent->updateGeometry();
+    }
+}
+
+
+/*!
     Returns a suitable size hint for the section specified by \a logicalIndex.
 
     \sa sizeHint(), defaultSectionSize(), minimumSectionSize(),
@@ -918,6 +934,18 @@ void QHeaderView::resizeSection(int logical, int size)
         d->doDelayedResizeSections();
         r = d->viewport->rect();
     }
+
+    // If the parent is a QAbstractScrollArea with QAbstractScrollArea::AdjustToContents
+    // then we want to change the geometry on that widget. Not doing it at once can/will
+    // cause scrollbars flicker as they would be shown at first but then removed.
+    // In the same situation it will also allow shrinking the whole view when stretchLastSection is set
+    // (It is default on QTreeViews - and it wouldn't shrink since the last stretch was made before the
+    // viewport was resized)
+
+    QAbstractScrollArea *parent = qobject_cast<QAbstractScrollArea *>(parentWidget());
+    if (parent && parent->sizeAdjustPolicy() == QAbstractScrollArea::AdjustToContents)
+        parent->updateGeometry();
+
     d->viewport->update(r.normalized());
     emit sectionResized(logical, oldSize, size);
 }
@@ -1225,7 +1253,7 @@ void QHeaderView::setSectionResizeMode(ResizeMode mode)
     property is set to true. This is the default for the horizontal headers provided
     by QTreeView.
 
-    \sa setStretchLastSection()
+    \sa setStretchLastSection(), resizeContentsPrecision()
 */
 
 void QHeaderView::setSectionResizeMode(int logicalIndex, ResizeMode mode)
@@ -1288,6 +1316,53 @@ QHeaderView::ResizeMode QHeaderView::sectionResizeMode(int logicalIndex) const
     return d->headerSectionResizeMode(visual);
 }
 
+/*!
+   \since 5.2
+   Sets how precise QHeaderView should calculate the size when ResizeToContents is used.
+   A low value will provide a less accurate but fast auto resize while a higher
+   value will provide a more accurate resize that however can be slow.
+
+   The number \a precision specifies how many sections that should be consider
+   when calculating the preferred size.
+
+   The default value is 1000 meaning that a horizontal column with auto-resize will look
+   at maximum 1000 rows on calculating when doing an auto resize.
+
+   Special value 0 means that it will look at only the visible area.
+   Special value -1 will imply looking at all elements.
+
+   This value is used in QTableView::sizeHintForColumn(), QTableView::sizeHintForRow()
+   and QTreeView::sizeHintForColumn(). Reimplementing these functions can make this
+   function not having an effect.
+
+   If \a resizeSectionsNow is set to true (default) it will do adjustment of sections by calling
+   resizeSections().  (regardless if the precision was changed).
+
+    \sa resizeContentsPrecision(), setSectionResizeMode(), resizeSections(), QTableView::sizeHintForColumn(), QTableView::sizeHintForRow(), QTreeView::sizeHintForColumn()
+*/
+
+void QHeaderView::setResizeContentsPrecision(int precision, bool resizeSectionsNow)
+{
+    Q_D(QHeaderView);
+    d->resizeContentsPrecision = precision;
+    if (resizeSectionsNow)
+        resizeSections();
+}
+
+/*!
+  \since 5.2
+  Returns how precise QHeaderView will calculate on ResizeToContents.
+
+  \sa setResizeContentsPrecision(), setSectionResizeMode()
+
+*/
+
+int QHeaderView::resizeContentsPrecision() const
+{
+    Q_D(const QHeaderView);
+    return d->resizeContentsPrecision;
+}
+
 // ### Qt 6 - remove this obsolete function
 /*!
     \obsolete
@@ -3512,6 +3587,19 @@ int QHeaderViewPrivate::adjustedVisualIndex(int visualIndex) const
     return visualIndex;
 }
 
+void QHeaderViewPrivate::setScrollOffset(const QScrollBar *scrollBar, QAbstractItemView::ScrollMode scrollMode)
+{
+    Q_Q(QHeaderView);
+    if (scrollMode == QAbstractItemView::ScrollPerItem) {
+        if (scrollBar->maximum() > 0 && scrollBar->value() == scrollBar->maximum())
+            q->setOffsetToLastSection();
+        else
+            q->setOffsetToSectionPosition(scrollBar->value());
+    } else {
+        q->setOffset(scrollBar->value());
+    }
+}
+
 #ifndef QT_NO_DATASTREAM
 void QHeaderViewPrivate::write(QDataStream &out) const
 {
@@ -3542,6 +3630,8 @@ void QHeaderViewPrivate::write(QDataStream &out) const
     out << int(globalResizeMode);
 
     out << sectionItems;
+    if (out.version() >= QDataStream::Qt_5_2)
+        out << resizeContentsPrecision;
 }
 
 bool QHeaderViewPrivate::read(QDataStream &in)
@@ -3593,6 +3683,10 @@ bool QHeaderViewPrivate::read(QDataStream &in)
     }
     sectionItems = newSectionItems;
     recalcSectionStartPos();
+
+    if (in.version() >= QDataStream::Qt_5_2)
+        in >> resizeContentsPrecision;
+
     return true;
 }