Avoid QRubberBand leaving artefacts in QListView

On hidpi screens, the painted edges of the rubberband can extend
beyond the selection rect because of scaling. Extend the area to be
updated by 2x frame width, when the rubberband changes.

Fixes: QTBUG-113432
Pick-to: 6.7 6.6 6.5
Change-Id: Ie7aec1fefdc3fbf71c63952b693f462697adf849
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/widgets/itemviews/qlistview.cpp b/src/widgets/itemviews/qlistview.cpp
index dc6046bd3f..a7f1931947 100644
--- a/src/widgets/itemviews/qlistview.cpp
+++ b/src/widgets/itemviews/qlistview.cpp
@@ -755,7 +755,10 @@ void QListView::mouseMoveEvent(QMouseEvent *e)
         && d->selectionMode != NoSelection) {
         QRect rect(d->pressedPosition, e->position().toPoint() + QPoint(horizontalOffset(), verticalOffset()));
         rect = rect.normalized();
-        d->viewport->update(d->mapToViewport(rect.united(d->elasticBand)));
+        const int margin = 2 * style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
+        const QRect viewPortRect = rect.united(d->elasticBand)
+                                       .adjusted(-margin, -margin, margin, margin);
+        d->viewport->update(d->mapToViewport(viewPortRect));
         d->elasticBand = rect;
     }
 }
@@ -769,7 +772,9 @@ void QListView::mouseReleaseEvent(QMouseEvent *e)
     QAbstractItemView::mouseReleaseEvent(e);
     // #### move this implementation into a dynamic class
     if (d->showElasticBand && d->elasticBand.isValid()) {
-        d->viewport->update(d->mapToViewport(d->elasticBand));
+        const int margin = 2 * style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
+        const QRect viewPortRect = d->elasticBand.adjusted(-margin, -margin, margin, margin);
+        d->viewport->update(d->mapToViewport(viewPortRect));
         d->elasticBand = QRect();
     }
 }