Allow greater control over layer rendering order

[nickofthyme]

Feature

Allower greater control over the layer rendering order on canvas layers. Should sync with legend and tooltip order somehow.

Proposed API

Very rough idea right now to start thinking about the best approach

// Render ordering
interface OrderFn = (series: SeriesIdentifier) => number; // number to use as global z-index
interface OrderSortFn = (seriesA: SeriesIdentifier, seriesB: SeriesIdentifier) => -1 | 0 | 1; // relative ordering of series
type Order = OrderFn | OrderSortFn | number // number would be the simplest ordering or spec
interface BasicSeriesSpec {
  order: Order;
}

// Edge clippings
interface EdgeClippingProps {
  lineWidth?: boolean; // including line width on edge
  points?: boolean; // including point radius on edge
  highlighter?: boolean; // include all highlighter elements outside of chart area
  padding?: number; // max padding for clippings
}
interface SettingsSpec {
  // not sure if Settings is the right place for this but it should be a global thing
  edgeClipping: EdgeClippingProps;
  ...
}

Related to #315, #303, #585 & #160

Examples

Overall ordering

Order rendering per spec, based on simple number or order.

Series ordering

Order rendering per series, overriding spec order. For example, select which line gets drawn on top of the other.

Edge clipping

Greater control for clipping at the edge for line widths and points

[markov00]

@nickofthyme do you think we can close this for now? does the new rendering sorting mechanism solves the request here?

[nickofthyme]

Yeah, I don't know why I grouped sorting with the edge clipping, I think that issue still stands but we can address that in a separate issue.