QQuickTableView: improve performance when scrolling with scrollbars

When flicking, the current implementation would load and unload
edges around the table until the new viewport was covered. The downside
of that strategy is that you if you move the viewport a long
distance in one go, you will need to load and unload edges hidden
outside the viewport until it catches up with the new viewport. It gets
even worse if you flick with a scrollbar, since then you can end up
flicking thousands of rows in one go. And this will keep tableview
busy loading and unloading edges for a "long" time.

This patch will fix this issue by checking how much the viewport
changes during a flick, and select a strategy based on that. So if the
viewport moves more than a page (which is the size of the viewport), it
will schedule a rebuild of the table from the viewports new location,
rather than trying to load and unload edges until it catches up.

Fixes: QTBUG-70704
Change-Id: I88909e118ec0759a7b7a305c19ccc6670af6263b
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

0 files changed, 0 insertions, 0 deletions