fastline controller

[benmccann]

This is an idea I wanted to run past you guys.

It's a far faster controller for drawing a line graph because it doesn't create any elements.

I made it a separate controller for experimenting, but I wonder if it should be combined with the main one. Also, it doesn't use the new fastpath code, so could probably be made faster still.

Features it disables:

• animation
• bezier and stepped lines and spanGaps: false
• drawing points (could be added back, but I didn't plan on it)
• tooltips (I'd like to add this back)

[kurkle]

How great performance improvement are we talking about?
I think this would be better off implemented externally. @etimberg what do you think?

[etimberg]

Could we keep this external until it's got enough features/performance to warrant moving to the core? I don't want to increase our bundle size too much

[benmccann]

It's about twice as fast. As we optimize the scale and other parts more then this will provide a larger improvement on a percentage basis.

I sent #6829 to allow implementing this externally

[benmccann]

I'll close this for now and consider whether to implement it externally or try to move forward in some other way with it