Support dragging

[MattiSG]

To add interactivity to my charts, I'd like to handle dragging events.

This was discussed in Gitter, here are the highlights:

• Usual dragging implementations have dragStart, drag and dragEnd.
• The callback functions should receive the scaled values.
• The callback functions should receive the current moving point, if any. This could be identified by the current identifiers passed to the onClick handler.
• Performance probably wouldn't allow redrawing the chart on each drag event; we should still have it in case the developer wants to do something outside from the chart with the fed data.

Demo of redrawing based on cursor position: http://plnkr.co/edit/KTkkC7gBLHnF3sxCA4rZ?p=preview

[chaosmail]

In the hackergarten event we worked on bar charts in the dev channel, mainly because of Typescript and Protractor; so this issue is still waiting for someone to solve it :)

[MattiSG]

Ok, thanks for the heads up! :) I'm off for the week so won't be able to look at this for now though. If no one else takes care of this issue, I'll contact you when I have some availability to work on it :)

Cheers, Matti

[davehun]

this would be very very helpful for us too

[lorem--ipsum]

Can we close this ? Dragging is supported in v2.