Implementation comparisons with Swift Charts

[heckj]

Swift Charts (available for iOS 16+, macOS 13+, and watchOS 9+) released into beta at WWDC 2022, with some really nice software that does all of what the initial plan for this repo aimed for, and more. In addition to basic charts, they cover down into accessibility and interactions for the charts.

Some of the choices the Apple API made where I took a different path makes things notably simpler for the Apple code:

• Explicit, single axis declarations (X and Y) independent of the marks themselves, and the marks implicitly use those axis declarations.
• Minimal or no real conversions for types other than Double for continuous data - you're expected to get it into Double before handing it over to the chart.
• breaking out the ticks (AxisTick, AxisMark, etc) that go into an Axis into separate components, building that up with an AxisContentBuilder. The result of which is consumed by ChartContentBuilder.
• their ChartRenderer has a method that renders into CGContext as well as one that renders into GraphicsContext.

I'd like to continue to enable the visualization tools, and one of my end goals was being able to create 3D interactive visualizations from data streams. With that in mind, its worthwhile to review the semantics of how Apple provided their API - and some of the released SwiftUI API design talk - with a refocus for this library away from just 2D generation, and over into 3D generation (SceneKit or RealityKit) with the idea to match into some clearly-coming-but-not-announced AR/VR capable device.