Support for remote desktop systems

Daniel Stone daniel at
Tue Aug 6 09:46:44 PDT 2013

Hi Andrew,
Nice to hear from you. :)

Unfortunately, the pretty blunt answer is that it's not the kind of
interface we're intending to support at the moment.  There are two
primary reasons behind this: the first is that by design, we tend to
put things like this in private, compositor-led, protocol.  So, when
you go to take a screenshot in Weston, the compositor spawns a client
which is then given a private interface - specifically for screenshots
- that no other client can see.  From this, the compositor would need
at least some involvement.

The second, which is a little more serious, is that the buffer
handling is totally abstract and not specified by the Wayland protocol
itself.  wl_buffer objects (which are not really transportable between
clients) can be created by the EGL stack, or SHM buffers, or, or, or.
There's not much getting around this, without the compositor being the
one to map the buffers into userspace and pull the content out.  This
is pretty much what the extant RDP compositor backend already does, as
I see you've noticed.

We're hoping that Weston, which has a pretty strong plugin
architecture, will serve as the base for many environments, so with
any luck targeting that will give you good reach.  The RDP compositor
backend, and screenshot/videocast clients should be able to serve as a
pretty good example of how to go about it.

Sorry to disappoint ...


On 1 August 2013 16:23, Andrew Wedgbury <andrew.wedgbury at> wrote:
> Hi all,
> I'm new to the list so please allow me to introduce myself - I work for RealVNC, and we are very keen to support Wayland-based desktops in our cross-platform remote desktop software. I was hoping to get some advice on how we should approach this.
> I've seen the RDP compositor in Weston, but I believe this only allows control of a "virtual" desktop, is that correct?
> What we would like is to be able to capture the screen output from a regular desktop, and ideally to get notified when updates occur. As I understand it, I don't believe there is anything that would allow us to do this at present via the Wayland client API. I understand there are security implications in allowing applications to see the output of other applications, so perhaps this is not the right approach.
> It is possible that we could do this by writing a module for Weston, but we would prefer a more generic solution that would work with other compositors (and could be used by other remote desktop systems), something like a remote control interface.
> Are there any such plans in the pipeline? Anything we could help with?
> ---
> Andrew Wedgbury <andrew.wedgbury at>
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