Re: [9fans] oneko for rio

["Douglas A. Gwyn" <gwyn@arl.army.mil>]

rob pike wrote:
> I agree.  I think I could probably puzzle out a way to implement
> oneko but it will not be easy, to put it mildly.

Similar apps on the DMD/MTG were able to use the full-display
Bitmap data structure (named "display"), also Smouse/RealMouse
for the full-display mouse cursor location.  Since the draw(3)
device interposes a file system between any (sub)window and the
root bitmap (background/desktop), there is no direct path for a
(sub)window process to access its containing window, and
furthermore, rio(1) is not in a position to intervene.

However, it would appear that all that is needed for this kind
of app is for /dev/screen to be writable (it is read-only for
some reason I don't understand).  Perhaps /dev/screen can
support chmod so even if it is provided to the process in a
read-only state that could be changed and then top-level
drawing could be done.  Or, anyone want to change line 31 of
/sys/src/cmd/rio/fsys.c to
	{ "screen",	Qscreen,	0600 ),
and try the experiment?  The absolute mouse position would be
determinable by adding the local position to the difference
in LLCs of /dev/screen and /dev/window; I don't know whether
the mouse position is allowed to be reported as negative, but
it should be.  (Some apps might then have to start checking,
but I suspect most would be okay.)

I have DMD/MTG source for eyes, swarm, and crabs if anyone
wants to try porting them.