Re: Support for remote desktop systems

2013-08-08 Thread Andrew Wedgbury 
Hi Daniel,

- Original Message -
 From: Daniel Stone dan...@fooishbar.org
 To: Andrew Wedgbury andrew.wedgb...@realvnc.com
 Cc: wayland-devel@lists.freedesktop.org
 Sent: Tuesday, 6 August, 2013 5:46:44 PM
 Subject: Re: Support for remote desktop systems
 
 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 ...
 

Thanks for the information. We'll concentrate on Weston for now then.

Very interesting looking at the screenshot/videocast example. As you say, 
Weston spawns the screenshot app, which is allowed access to a private 
interface which it uses to obtain the screenshot. Not sure whether you'd want 
Weston to launch a VNC server in this way though, it seems like the user should 
have a bit more control over this, but there does need to be some mechanism to 
control access to the private interface it would need to use.

BTW, is there any reason the video recorder works differently? - it writes the 
capture file directly from within Weston rather than go via an external app. 
Just curious.

---
Andrew Wedgbury andrew.wedgb...@realvnc.com
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Re: Support for remote desktop systems

2013-08-06 Thread Daniel Stone 
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 ...

Cheers,
Daniel

On 1 August 2013 16:23, Andrew Wedgbury andrew.wedgb...@realvnc.com 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.wedgb...@realvnc.com
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