Re: [Sugar-devel] Multi-touch test activity

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Re: [Sugar-devel] Multi-touch test activity

forster@ozonline.com.au
See also http://dev.laptop.org/ticket/12161

Tony

> Hi folks,
>
> I made a simple Sugar activity to test the XO-4's multi-touch screen:
>
> http://activities.sugarlabs.org/en-US/sugar/addon/4611/
>
> It works fine most of the time. Sometimes the touch contact ends unexpectedly without lifting the finger.
>
> It also demonstrates that the Neonode sensor's two touch points are not independent: If you put down two fingers simultaneously, it does not know in which of the 4 possible positions the two fingers are (it only knows that 2 horizontal and 2 vertical beams got obstructed) and so it has to guess. Also, the tracking sometimes "switches over", e.g. when doing a pinch-zoom using your right hand.
>
> For activity developers this means that pinch/zoom and rotation gestures will work fine, but we cannot rely on truly independent touch tracking.
>
> Also, two-finger sweeps are not always recognized as two fingers if they are held close together.
>
> Nonetheless, it is fun to play with if you happen to have an XO-4 Touch :)
>
> Source code:
>
> http://git.sugarlabs.org/testmultitouch/mainline
>
> Patches welcome, but I want to keep the source simple, this is not going to become another Paint activity.
>
> - Bert -
>
> PS: Could some admin please delete the accidental non-mainline repo in http://git.sugarlabs.org/testmultitouch/ ? Keep "mainline", remove "testmultitouch". Thanks.
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Re: [Sugar-devel] Multi-touch test activity

Bert Freudenberg
Ah, thanks. I wasn't even going to file a bug report about the aliasing because that is a limitation inherent to the kind of sensor we have.

Thinking about this a little bit more, only pinch/zoom will be fine. Rotation can still go in the wrong direction if the driver guesses the intersections wrongly.

- Bert -

On 2012-11-05, at 01:55, [hidden email] wrote:

> See also http://dev.laptop.org/ticket/12161
>
> Tony
>
>> Hi folks,
>>
>> I made a simple Sugar activity to test the XO-4's multi-touch screen:
>>
>> http://activities.sugarlabs.org/en-US/sugar/addon/4611/
>>
>> It works fine most of the time. Sometimes the touch contact ends unexpectedly without lifting the finger.
>>
>> It also demonstrates that the Neonode sensor's two touch points are not independent: If you put down two fingers simultaneously, it does not know in which of the 4 possible positions the two fingers are (it only knows that 2 horizontal and 2 vertical beams got obstructed) and so it has to guess. Also, the tracking sometimes "switches over", e.g. when doing a pinch-zoom using your right hand.
>>
>> For activity developers this means that pinch/zoom and rotation gestures will work fine, but we cannot rely on truly independent touch tracking.
>>
>> Also, two-finger sweeps are not always recognized as two fingers if they are held close together.
>>
>> Nonetheless, it is fun to play with if you happen to have an XO-4 Touch :)
>>
>> Source code:
>>
>> http://git.sugarlabs.org/testmultitouch/mainline
>>
>> Patches welcome, but I want to keep the source simple, this is not going to become another Paint activity.
>>
>> - Bert -
>>
>> PS: Could some admin please delete the accidental non-mainline repo in http://git.sugarlabs.org/testmultitouch/ ? Keep "mainline", remove "testmultitouch". Thanks.
>

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Re: [Sugar-devel] Multi-touch test activity

Martin Langhoff
On Sun, Nov 4, 2012 at 8:29 PM, Bert Freudenberg <[hidden email]> wrote:
> Ah, thanks. I wasn't even going to file a bug report about the aliasing because that is a limitation inherent to the kind of sensor we have.

There are of course limitations, but we are in the process of tuning
and tightening things on the IR.

All sensor types have some forms of aliasing. If you know how, you can
confuse capacitive sensors too :-)



m
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Re: [Sugar-devel] Multi-touch test activity

Bert Freudenberg
On 2012-11-06, at 23:50, Martin Langhoff <[hidden email]> wrote:

> On Sun, Nov 4, 2012 at 8:29 PM, Bert Freudenberg <[hidden email]> wrote:
>> Ah, thanks. I wasn't even going to file a bug report about the aliasing because that is a limitation inherent to the kind of sensor we have.
>
> There are of course limitations, but we are in the process of tuning
> and tightening things on the IR.

Okay. The breaking up of touch contacts was surprising. I attached a photo here:

        http://dev.laptop.org/ticket/12282

> All sensor types have some forms of aliasing. If you know how, you can
> confuse capacitive sensors too :-)

Yep. You may find my updated activity version useful in testing:

        http://activities.sugarlabs.org/en-US/sugar/addon/4611/

I modified it to keep displaying the last touches.

Single-touch works pretty well already, tweaking multi-touch sounds good :)

- Bert -


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