Vega-lite: Make default selection events work on mobile

[kanitw]

Currently, our default selection events are only for desktop applications.

[domoritz]

@mattijn showed how you can add touch interactions to VL right now in https://github.com/vega/vega-lite/issues/4208#issuecomment-471757641 but we should see how we can support this by default.

[kanitw]

@domoritz said that Falcon has some example events that work on mobile too.

[luciodale]

Is there any progress on this feature? :)

[domoritz]

Not yet but we would be thrilled about PRs along those lines.

[donghaoren]

@domoritz, I'd love to give this a try, could you point me to the Falcon code that handles mobile events?

[domoritz]

It's all in https://github.com/uwdata/falcon/blob/master/src/views/histogram.ts. You can try Falcon on your phone or iPad as well: https://uwdata.github.io/falcon/flights/.

[keckelt]

Suggestion from my side:

• Single selection: tap
• Multi selection: tap to select, tap again to deselect, i.e. like with toggle set to true
• 1D Interval: the ones from Falcon (I came here to see if the falcon brush is planned to become default 🙂 )
• 2D Interval: 🤷‍♂ the grabbers fromfalcon will not work if the selected area is small, but I'm not sure if there is a reasonable alternative

Falcon brush: