multitouch

[Daniel Stone]

Hi,

On Mon, Mar 01, 2010 at 04:25:48PM +0300, Artem Ananiev wrote:
> On 3/1/2010 3:41 PM, Daniel Stone wrote:
>> On Mon, Mar 01, 2010 at 12:42:40PM +0100, Bradley T. Hughes wrote:
>>> On 03/01/2010 12:22 PM, ext Daniel Stone wrote:
>>>> and so on, and so forth ... would this be useful enough to let you take
>>>> multi-device rather than some unpredictable hybrid?
>>>
>>> It would for me, absolutely. This avoids the multi-device grab problem
>>> described by Peter earlier, but I'm unsure how well it works given that
>>> we still lack the user/gesture context (as described by Peter).
>>
>> Any suggestions? :) Reference to how OS X and/or Windows implement it
>> would be welcome too.
>
> In a few words, Windows expects all the subsequent touch events to occur  
> on the same window as the first touch. If I press another window, the  
> corresponding WM_TOUCH notification is just skipped - not sent to the  
> client. I'm not sure about explicit mouse grab (SetCapture() call), 
> though.
>
> Gestures and touch events are mutually exclusive on Windows: one can  
> either receive WM_GESTURE or WM_TOUCH messages, but not the both. In the  
> latter case, I can feed the gestures engine manually, though, but again,  
> if I don't receive touch events for different windows, I can't make the  
> gestures engine recognize gestures for different windows.
>
> In other words, Windows doesn't bother about user/gesture context at  
> all. If a client needs some complex manipulations (e.g. multiple users  
> interacting a large touch table), the native system doesn't provide any  
> help for that - just listen to the low-level touch events and write your  
> custom gestures recognizer.

OK, thanks for that. :) So it's basically what you'd have now if you had
a driver which did multitouch as multiple axes in a single device.

Cheers,
Daniel
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