Instead of having a very large region represent an infinitely large
region, use NULL, and use the calculated input region from the
MetaWaylandSurface if the constraint region was not set.
https://bugzilla.gnome.org/show_bug.cgi?id=762661
The when surface->input_region is NULL, it should be interpreted as the
whole surface region. If not, the effective input region is the
intersection of the buffer region and the input region set by
wl_surface.set_input_region. Add
meta_wayland_surface_calculate_input_region() that does this
calculation.
https://bugzilla.gnome.org/show_bug.cgi?id=762661
The constraint may be destroyed before the client destroyes the
protocol object, for example if a oneshot constraint was disabled by
alt-tab. Therefore we need to NULL check the constraint in request
handlers and ignore any requests to defunct objects.
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
