The small catch is that MtkRegion (and pixman regions) "optimize away"
0-size rectangles, so a 0-sized region will always be seen as having
a 0,0 origin. We don't want that, so transfer the origin separately from
the region.
While at it, make the Wayland pointer lock use one such 0-size region,
to avoid the 1x1px wiggle room that it currently has (accounting for subpixel
motion).
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3420>
The min distance to the right/bottom edge depends on Wayland concepts
(wl_fixed_t) and eventually geometry scale. Move the logic the Wayland
side of the pointer constraints machinery to avoid the backend trying to
figure this out without the proper data.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2460>
The wp_pointer_constraints protocol is a protocol which enables clients
to manipulate the behavior of the pointer cursor associated with a seat.
Currently available constraints are locking the pointer to a static
position, and confining the pointer to a given region.
Currently locking is fully implemented, and confining is implemented for
rectangular confinement regions.
What else is lacking is less troublesome semantics for enabling the lock
or confinement; currently the only requirement implemented is that the
window that appears focused is the one that may aquire the lock.
This means that a pointer could be 'stolen' by creating a new window that
receives active focus, or when using focus-follows-mouse, a pointer
passes a window that has requested a lock. This semantics can be changed
and the protocol itself allows any semantics as seems fit.
https://bugzilla.gnome.org/show_bug.cgi?id=744104
