diff options
Diffstat (limited to 'src/gui/painting/qbackingstore.cpp')
| -rw-r--r-- | src/gui/painting/qbackingstore.cpp | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/src/gui/painting/qbackingstore.cpp b/src/gui/painting/qbackingstore.cpp index 801397751b..e3d18512dd 100644 --- a/src/gui/painting/qbackingstore.cpp +++ b/src/gui/painting/qbackingstore.cpp @@ -236,11 +236,16 @@ QSize QBackingStore::size() const */ bool QBackingStore::scroll(const QRegion &area, int dx, int dy) { - Q_UNUSED(area); - Q_UNUSED(dx); - Q_UNUSED(dy); - - return d_ptr->platformBackingStore->scroll(QHighDpi::toNativeLocalRegion(area, d_ptr->window), QHighDpi::toNativePixels(dx, d_ptr->window), QHighDpi::toNativePixels(dy, d_ptr->window)); + // Disable scrolling for non-integer scroll deltas. For this case + // the the existing rendered pixels can't be re-used, and we return + // false to signal that a repaint is needed. + const qreal nativeDx = QHighDpi::toNativePixels(qreal(dx), d_ptr->window); + const qreal nativeDy = QHighDpi::toNativePixels(qreal(dy), d_ptr->window); + if (qFloor(nativeDx) != nativeDx || qFloor(nativeDy) != nativeDy) + return false; + + return d_ptr->platformBackingStore->scroll(QHighDpi::toNativeLocalRegion(area, d_ptr->window), + nativeDx, nativeDy); } /*! |