Clients reading their surface position on screen

Thomas Voß thomas.voss at
Tue Jul 22 08:01:50 UTC 2014

Hey all,

so reading Gerry's initial mail, it seems to me that autopilot does
not actually want to deal with absolute screen coordinates (and take
on the burden of figuring out multi-monitor, multi-dpi cases on its
own) but instead wants to say: Please Mr. Mir, for this surface with
ID id, send an event of type Y with these attributes. Where Y is most
likely touch events and the attributes are surface-relative
coordinates. With that, we can leverage the existing mir logic, while
keeping AP free of global knowledge.



On Tue, Jul 22, 2014 at 9:58 AM, Daniel van Vugt
<daniel.van.vugt at> wrote:
> If accessibility and Autopilot can live with a point (centre of a widget)
> rather than needing an accurate region then we can just deal in one point
> per widget. And that keeps anpok's dream alive of perfect input mapping in
> 3D shells :)
> On 22/07/14 15:52, Christopher James Halse Rogers wrote:
>> On Tue, Jul 22, 2014 at 11:23 AM, Luke Yelavich
>> <luke.yelavich at> wrote:
>>> On Tue, Jul 22, 2014 at 09:42:42AM EST, Gerry Boland wrote:
>>>>  Hey folks,
>>>>  in working on QtCompositor, I stumbled across a problem ([1]).
>>>>  Autopilot needs to know the position of items in an application
>>>>  (buttons, etc) in screen coordinates - not surface. It needs that as it
>>>>  generates inputs via uevent, which are defined in screen coordinates.
>>> Qt's accessibility framework also needs to be able to present this
>>> information via at-spi to accessibility tools such as Orca.(1) This is
>>> probably something that is more to do with Qt internals working with
>>> Mir, but even though this is primarily about autopilot, keeping
>>> accessibility requirements in mind when thinking about this is
>>> probably also relevant.
>> My memory of our discussions in Malta was that it seemed like a good
>> idea for Mir itself to take some part of the role of the at-spi registry
>> and have toolkits report the surface-relative positions of their
>> widgets. Then Mir can provide (appropriately permissioned) accesibility
>> applications the absolute positions of the various widgets.
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