multitouch

[Artem Ananiev]

On 3/1/2010 6:09 PM, Bradley T. Hughes wrote:
> On 03/01/2010 03:14 PM, ext Daniel Stone wrote:
>> And from the NSTouch (OS X) class documentation:
>> Touches do not have a corresponding screen location. The first touch
>> of a touch collection is latched to the view underlying the cursor
>> using the same hit detection as mouse events. Additional touches on
>> the same device are also latched to the same view as any other
>> touching touches. A touch remains latched to its view until the
>> touch has either ended or is cancelled.
>
> Very quickly, since I forgot to mention it in my original reply:
>
> Bear in mind that this documentation is for OS X, and current Apple
> hardware only has multi-touch support via track-pads. There is no
> touch-screen hardware running Mac OS X today. It's either iPhone, iPod
> touch, or the upcoming iPad. iPhone and iPod touch use a different API
> than the above, UITouch instead of NSTouch, which actually does give
> on-screen locations (iirc).

Note that NSTouch provides the information about the device, in 
particular deviceSize. Coupled with normalizedPosition, this gives us an 
on-screen location.

Thanks,

Artem

> The multi-focii discussions really only apply to multi-touch capable
> touch screens, not to laptop track-pads or external multi-touch capable
> tablets like some (all?) of the Wacom Bamboo tablets.
>