Donut Chart

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"}
])

Section

Set hole: 0.4 (or any 0–1 value) to cut a hole in the centre of the pie, creating a donut chart. Use a paper-referenced annotation to add text in the centre.

alias Plotly.{Figure, Pie}

Figure.new()
|> Figure.add_trace(
  Pie.new(
    labels: ["Residential", "Non-Residential", "Utility"],
    values: [19, 26, 55],
    hole: 0.4,
    name: "GHG Emissions"
  )
)
|> Figure.update_layout(
  title: "Donut Chart",
  height: 450,
  width: 500,
  annotations: [
    %{
      text: "GHG",
      x: 0.5,
      y: 0.5,
      font: %{size: 20},
      showarrow: false
    }
  ]
)
|> Plotly.show()

Side-by-side donut charts with domain:

Figure.new()
|> Figure.add_trace(
  Pie.new(
    values: [16, 15, 12, 6, 5, 4, 42],
    labels: ["US", "China", "EU", "Russia", "Brazil", "India", "Rest"],
    domain: %{x: [0, 0.45]},
    name: "CO2",
    hoverinfo: "label+percent+name",
    hole: 0.4
  )
)
|> Figure.add_trace(
  Pie.new(
    values: [27, 11, 25, 8, 1, 3, 25],
    labels: ["US", "China", "EU", "Russia", "Brazil", "India", "Rest"],
    domain: %{x: [0.55, 1]},
    name: "GHG",
    hoverinfo: "label+percent+name",
    hole: 0.4
  )
)
|> Figure.update_layout(
  title: "CO2 vs GHG Emissions",
  height: 400,
  annotations: [
    %{text: "CO2", x: 0.18, y: 0.5, showarrow: false, font: %{size: 16}},
    %{text: "GHG", x: 0.82, y: 0.5, showarrow: false, font: %{size: 16}}
  ]
)
|> Plotly.show()