Re: maxTouchPoints on platforms that have less granular information

That sounds perfect, thanks Jacob!

On Thu, Oct 31, 2013 at 2:29 PM, Jacob Rossi <>wrote:

> Given a platform that has less granular information than required, I think
> your approach (minimum guaranteed) is the best.  I'm OK with adding a note.
> But a non-normative note cannot use RFC2119 keywords, like "should." [1]
>  Here's an alternative:
> "Note: maxTouchPoints is often used to ensure that the interaction model
> of the content can be recognized by the current hardware. UI affordances
> can be provided to users with less capable hardware. On platforms where the
> precise number of touch points is not known, the minimum number guaranteed
> to be recognized is provided. Therefore, it is possible for the number of
> recognized touch points to exceed the value of maxTouchPoints."
> -Jacob
> [1]
> On Thu, Oct 10, 2013 at 3:36 PM, Rick Byers <> wrote:
> I just learned that Android doesn't have an API to report the exact number
> of touch points supported.  Instead it has a few levels (1, 2+, 5+).  See
> .
> Should we consider adding a non-normative note or something suggesting how
> such platforms should implement this API?  Eg:
> Note: some platforms may not report the precise number of touch points
> available.  On such platforms, this API should return the minimum
> guaranteed number of points that an application can rely on being
> available.  For example, on Android systems
> I.e. this API should be used to control the addition of additional UI to
> compensate for the lack of sufficient touch points (such as showing zoom
> controls on a single-finger device), not as a limit on the number of touch
> points that should actually be handled by the application.
> Sorry I wasn't aware of this as a potential issue sooner.
> Rick

Received on Thursday, 31 October 2013 18:47:35 UTC