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[mbostock]

Fixes #39. Supersedes #38.

Plot.plot({
  grid: true,
  inset: 10,
  x: {
    type: "log",
    label: "Population →"
  },
  y: {
    label: "↑ Inequality"
  },
  color: {
    type: "diverging",
    reverse: true,
    symmetric: false
  },
  marks: [
    Plot.arrow(data, {
      x1: "POP_1980",
      y1: "R90_10_1980",
      x2: "POP_2015",
      y2: "R90_10_2015",
      bend: true,
      stroke: d => d.R90_10_2015 - d.R90_10_1980
    }),
    Plot.text(data, {
      x: "POP_2015",
      y: "R90_10_2015",
      text: d => d.highlight && d.nyt_display,
      dy: -6
    })
  ]
})

TODO

• Allow the arrowhead length to be configurable (as a multiple of strokeWidth)
• Allow the arrowhead angle to be configurable
• Allow the bend angle to be configurable
• Provide a separate Plot.swoop for a bendy arrow Provide a default bend angle with bend: true
• Documentation

Potential future work:

• Different styles of arrowheads, maybe filled?
• insetStart and insetEnd options to leave room for terminal dots?

On arrowhead styles, we could do this with markers instead of computing the paths as in #38. But doing it as a stroked path felt like a simpler starting point… we could always revisit in the future.

[Fil]

With a reminder to document the new arrow insets