multitouch

[Artem Ananiev]

On 3/1/2010 4:56 PM, Bradley T. Hughes wrote:
> On 03/01/2010 01:55 PM, ext Daniel Stone wrote:
>> I don't really see the conceptual difference between multiple devices
>> and multiple axes on a single device beyond the ability to potentially
>> deliver events to multiple windows. If you need the flexibility that
>> multiple devices offer you, then just use multiple devices and make your
>> internal representation look like a single device with multiple axes.
>
> This is where the context confusion comes in. How do we know what the
> user(s) is/are trying to do solely based on a set of x/y/z/w/h
> coordinates? In some cases, a single device with multiple axes is
> enough, but in other cases it is not.
>
> On a side note, I have a feeling this is why things like the iPhone/iPad
> are full-screen only, and Windows 7 is single-window multi-touch only.
>
>> Given that no-one's been able to articulate in much detail what any
>> other proposed solution should look like or how it will actually work
>> in the real world, I'm fairly terrified of it.
>>
>> Can you guys (Bradley, Peter, Matthew) think of any specific problems
>> with the multi-layered model? Usecases as above would be great, bonus
>> points for diagrams. :)
>
> I'm concerned about the event routing and implicit grabbing behaviour,
> specifically. I don't know enough about the internals to really put my
> concerns into words or link to code in the server.
>
> Use-cases? Collaboration is the main use-case. Class rooms, meeting
> rooms, conferences are ones that I often think about. Think about the
> GIMP having multi-user and multi-touch support so that art students
> could work together on a multi-touch table top. I think the MS Surface
> marketing videos are a good indication of what could be done as well.

GIMP and MS Surface are really single-application use cases. Are there 
any examples of collaboration when multiple applications are involved?

> One thing that we definitely want is for normal button and motion events
> for one of the active touch-points over a client window. As Peter
> pointed out, we shouldn't have to rewrite the desktop to support
> multi-touch. In addition to specialized applications like I described
> above, we definitely want "normal" applications to remain usable in such
> an environment (I can definitely see someone bringing up a terminal
> and/or code editor just for themselves to try out an idea that they get
> while in a meeting).
>
> (Sorry for the lack of diagrams, my ascii-art kung-fu is non-existent.
> How about a video? http://vimeo.com/4990545)

It looks like an example of a single client handling all the low-level 
touch events. I really doubt that all the images on the video are 
different windows :) All the grabs and gestures seem to be implemented 
on the client side as well.

Thanks,

Artem