[RFC] Multitouch proposal v2 + implementation

[Ping Cheng]

On Wed, Sep 22, 2010 at 7:52 PM, Chase Douglas
<chase.douglas at canonical.com> wrote:
> On Mon, 2010-09-20 at 10:29 -0700, Ping Cheng wrote:
>> On Sun, Sep 19, 2010 at 9:45 PM, Daniel Stone <daniel at fooishbar.org> wrote:
>> > Hi all,
>> > This is my second draft of the multitouch proposal, along with a fairly
>> > complete implementation; patchsets for inputproto, xserver,
>> > xf86-input-evdev, libXi and xinput follow.
>> >
>> > This is more or less half way between Peter's proposal and my original
>> > one: it doesn't use valuators anymore, but it has a different, and
>> > hopefully more workable, approach to grabbing.
>>
>> I have a corner case that I'd like to know how you address it.
>>
>> How do we deal with the single touch case for multi-touch devices?
>> Shouldn't we still post valuator for single touch events so MT devices
>> can perform single touch functions while the touch is not grabbed by
>> the client? The single touch use case can occur before and after the
>> client grabs the MT events.
>
> I don't think we can post single-touch emulated events while MT events
> are grabbed because you'll get inconsistent handling by legacy X clients
> and XI 2.1 aware clients. I think we'll need to hold single-touch events
> until the MT events that define them are released.

No, I am not talking about sending single touch event while the MT
data is grabbed. I am talking about before and after it is grabbed.
That is why I said it is a "corner case".

Ping