Make scrollZoom speed configurable

I find scrollZoom speed painfully slow. Making this configurable may mean propagating a scale factor to some other gl modules or something, but then again it might just be a simple scalar. Maybe scrollZoomSpeed?

(Side note: it’s not clear to me why scrollZoom is camelCased and belongs to config instead of to layout.)

I don’t think it’s entirely straightforward to get the speed itself just right across browsers and system configs, but maybe this is something: http://stackoverflow.com/questions/5527601/normalizing-mousewheel-speed-across-browsers#answer-30134826

[mzechmeister]

As a quick hack one can adjust manually the hardcoded normalisation factor in plotly.min.js:

var r=-e.deltaY;if(isFinite(r)||(r=e.wheelDelta/10),isFinite(r)){var n,i=Math.exp(-Math.min(Math.max(r,-20),20)/200),...

I replaced /200 by /10.

[danielfrunza]

If using in Javascript, I solved this by overtaking the wheel event (capture phase) and emitted my own event with modified deltaY. This works on cartesian plots, I did not check others.

function handler(event)
{
      if (!event.isTrusted) return;
      event.stopPropagation();
      var newEv = new WheelEvent('wheel', {
        clientX: event.clientX,
        clientY:event.clientY, 
        deltaY:event.deltaY*2,
      });
      event.target.dispatchEvent(newEv);
}

What is the element that you attached the ‘handler’? I tried on ‘document’ and plot element and does not work…