Color gradients?

[mbostock]

It’d be nice to have a way to specify a color gradient, presumably spanning the chart area in either x or y, with some given color stops.

[mbostock]

Gradients on links, bars, and rects would also be lovely to indicate direction, as here:

[Fil]

related: #362

[Fil]

may be fixed by #700 (it doesn't allow the gradients to be based on the data, but we can't realistically cover every use case: if one needs to compute gradients from data, there is still room to do it with vanilla JS or D3 (?))

[mbostock]

Pretty close, but it would be much nicer if you could express inline syntax for a gradient rather than having to create the linearGradient element in SVG. I think we could do this by writing a CSS parser for the linear-gradient function. This would create a linearGradient element under the hood with a dynamic id.

https://developer.mozilla.org/en-US/docs/Web/CSS/gradient/linear-gradient()