Debounce/throttle mouse events

[martinRenou]

We should probably debounce or throttle most of the mouse events (pan, zoom etc) in order to improve performances

[martinRenou]

Example of debounce being used in bqplot https://github.com/bqplot/bqplot/blob/dbc639836e58909250cf2ceb93aaca9e2c77d3d8/js/src/Figure.ts#L45 for preventing to relayout the plot too much during a window resize.

[asteppke]

Without throttling a bad user experience can be triggered if the backend requires x milliseconds to generate a new plot but the mouse events are arriving every y milliseconds with y < x. So this feature would help especially with complex plots.

At the moment without this one can stumble into almost unusable pan and zoom behavior. To keep a smooth & fast feeling it might be an idea to calculate on the frontend side how long the backend required to render (x milliseconds) and then make sure that the throttling always sends update requests that are not faster than, e.g. y =1.25 * x. This would prevent that requests pile up and the interface becomes very sluggish.

[martinRenou]

I guess it's difficult to compute the time it takes for the back-end to process a zoom/pan from the front-end, as the front-end doesn't know if the messages it receives are in response of the zoom/pan or something else.

I am making it configurable for now.

fig.canvas.pan_zoom_throttle = 300  # Throttling of 300ms