[Weston] More discussion about weston output relative motion algorithm

[Pekka Paalanen]

On Wed, 7 May 2014 03:26:56 +0000
"Wang, Quanxian" <quanxian.wang at intel.com> wrote:

> Thanks Pq's comment. Before you continue my comment, I mentioned one point.
> This is output movement algorithm and it is completely different with pre-configuration of output in weston.ini.
> For output, no alive, no movement.
> If you want to keep pre-configuration in weston.ini when output change, just keep it in some place and follow it when pre-defined output is plugged or unplugged. But anyway, it is a static configuration.  It is conflict with dynamic output movement.
> 

Of course it is, but users expect both to work at the same time, not
have an option to choose between dynamic and static configuration. They
want to configure what the dynamic code will do on hotplug, hence these
two cases are inseparable.

The weston-randr protocol could be seen as a way to modify the static
configuration in-memory and then trigger a re-layout.

Btw. there is no reason to avoid negative global coordinates. If you
have output A at 0,0 and add output B to the left of it, it is
perfectly valid to put B at -widthB,0. You *can* add to the left or
above without moving all the existing outputs. Also nothing says that
you have to have an output with origin at 0,0. (There may be bugs, but
that is all.)

If you haven't, and I certainly have not, you really should
study how existing monitor layout algorithms work. Do not set out to
replicate them as is, but find out how they solve the problems and
whether those solutions would be applicable here.

For getting this work forward and upstream, I think it is much less
controversial to first expand weston.ini to allow setting other than
just horizontal line of outputs. That would be interesting to a lot
more people than the dynamic configuration protocol, and you would
still need to deal with hotplug.

Btw. I don't understand the comment "no alive, no movement".


Thanks,
pq