On 10/08/2010 05:10 PM, Chase Douglas wrote: > On Fri, 2010-10-08 at 13:37 +0200, Henrik Rydberg wrote: >> On 10/05/2010 10:22 PM, Chase Douglas wrote: >> [...] >> >>> The reason this is useful is to lower the latency when there's >>> system-wide and application specific gesture recognition to be >>> performed. It requires a trust of the client applications to not handle >>> the events as though they owned them, but X trusts client applications >>> with lots of similar things today without issue. >> >> >> It seems to me that the idea of tentative events is not so much about >> latency as >> it is about implementing user feedback which helps resolve ambiguities. > > It's the latency to the user feedback that's important. In my mind, > these two concepts are one in the same. > >> There are at least three stages in gesture recognition in this respect. In >> the >> first stage, the engine builds up a reaction based on user input, from >> nothing >> to something. I see no reason to send this buildup anywhere at all. In the >> second stage, something is happening, and the user may need feedback from the >> system to tell that something has been registered. This is equivalent to our >> notion of gesture primitives, and could well be represented by tentative >> events, >> although I see no compelling reason to change views. The third stage is to >> perform a user-approved gesture, which is on a higher level than what we have >> implemented so far, and could be a good target for geis. > > The sticky point comes when we need to handle the possibility for both > gestures and low-latency multitouch input. For example, think of the > three finger hold to unlock many finger MT and gestures occurring over a > paint application. With the proposed XI 2.1 passive grabbing paradigm, > gimp will receive tentative events and may start painting, knowing that > it will need to undo those paints if the events should be discarded. > This should occur as immediately as possible after touches hit the > screen.
I agree that tentative events allows the possibility to start painting and later rollback. I do not see how grabbing affects this particular solution. Cheers, Henrik _______________________________________________ Mailing list: https://launchpad.net/~multi-touch-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~multi-touch-dev More help : https://help.launchpad.net/ListHelp
