Just like X11/XFixes behaves, the current cursor is not affected
by its visibility, so it can be queried while invisible (possibly
to be replaced).
For this, keep an extra effective_cursor pointer that will be
either equal to displayed_cursor (maybe a bit of a misnomer now)
or NULL if the cursor is invisible. The MetaCursorRenderer
management is tied to the former, and the ::cursor-changed signal
emission to the latter.
https://bugzilla.gnome.org/show_bug.cgi?id=754806
To be able to render the pointer cursor sprite at sub-(logical)-pixel
positions, track the pointer position using floats instead of ints.
This also requires users of the cursor sprite rect to deal with
floating points, when e.g. finding the logical monitor etc.
https://bugzilla.gnome.org/show_bug.cgi?id=765011
We expect that meta_screen_set_cursor while grabbed will properly
set the cursor on the root window. Make sure this works by simply
always using the root cursor when we have an active grab.
Right now this just has all of the files in one directory. We'll
be introducing more structure to this in the future, and build
a proper backend system.
