discussion about touch events

Assaf Yavnai assaf.yavnai at oracle.com
Mon Nov 11 04:02:56 PST 2013

The ascii sketch looked fine on my screen before I sent the mail :( I 
hope the idea is clear from the text
(now in the reply dialog its also look good)

On 11/11/2013 12:51 PM, Assaf Yavnai wrote:
> Hi Guys,
> I hope that I'm right about this, but it seems that touch events in 
> glass are translated (and reported) as a single point events (x & y) 
> without an area, like pointer events.
> AFAIK, the controls response for touch events same as mouse events 
> (using the same pickers) and as a result a button press, for example, 
> will only triggered if the x & y of the touch event is within the 
> control area.
> This means that small controls, or even quite large controls (like 
> buttons with text) will often get missed because the 'strict' node 
> picking, although from a UX point of view it is strange as the user 
> clearly pressed on a node (the finger was clearly above it) but 
> nothing happens...
> With current implementation its hard to use small features in 
> controls, like scrollbars in lists, and it almost impossible to 
> implement something like 'screen navigator' (the series of small dots 
> in the bottom of a smart phones screen which allow you to jump 
> directly to a 'far away' screen)
> To illustrate it consider the bellow low resolution sketch, where the 
> "+" is the actual x,y reported, the ellipse is the finger touch area 
> and the rectangle is the node.
> With current implementation this type of tap will not trigger the node 
> handlers
>                 __
>               /     \
>              /       \
>        ___/ __+_ \___    in this scenario the 'button' will not get 
> pressed
>        |    \         /    |
>        |___\ ___ / __ |
>               \___/
> If your smart phone support it, turn on the touch debugging options in 
> settings and see that each point translate to a quite large circle and 
> what ever fall in it, or reasonably close to it, get picked.
> I want to start a discussion to understand if my perspective is 
> accurate and to understand what can be done, if any, for the coming 
> release or the next one.
> We might use recently opened RT-34136 
> <https://javafx-jira.kenai.com/browse/RT-34136> for logging this, or 
> open a new JIRA for it
> Thanks,
> Assaf

More information about the openjfx-dev mailing list