Re: [gtk-vnc-devel] [PATCH 2/7] Add support for LastRect encoding 2008-11-20 Federico Mena Quintero <federico novell com>

[Peter Rosin <peda lysator liu se>]

Den 2008-12-18 17:27 skrev Daniel P. Berrange:
> I'm not entirely clear what this encoding does ? It seems to
> be just a no-op update, and break out of processing the rects
> off the wire.

That fits my understanding as well.

> But if the sever has sent n_rects=16 and this ooccurs as the
> 8th rect, why didn't the server just send 8 rects in the first
> place ? What happens to the rest of the data on the wire for
> the remaining rects in this update once we break out of the 
> loop. We surely need to still consume them off the wire ?

I believe the idea is that the server can start sending the
update before it knows exactly how many rects it will need for
the update. It can thus state that the update will contain at
least some number of rects (probably 65535) and then end the
update at will later. So, there is no need to consume the
trailing rects, the server is not supposed to add any rects
after the "last rect". I imagine that in this specific case
e.g. a ptr movement rect can be inserted in the middle of a
number of tight rects, even if the ptr movement happened after
the update "started".

All this to improve responsiveness on slow links.

Cheers,
Peter