QDesktopWidget::screenNumber(QWidget*): check virtual sibling screens

Find the root widget only when more than one virtual desktop exists
and find the screen index using virtual siblings from this root
widget.

Use intersecting rects instead of middle point to obtain the screen.
This can help to get the screen index when the middle point is outside
the screen geometry, but part of the window is still on the screen.

If the widget is completely outside the screen geometry, -1 is
returned.

This commit amends: a6b2a4642f07cd6e52b447e1e441b257990a8d03

Change-Id: I80247fc1956a82c487ee6f728d1576bf48b28748
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>

0 files changed, 0 insertions, 0 deletions