Advanced Violin Plot

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

Section

Combining all violin options in one chart:

• box: %{visible: true} — overlays a box plot inside the violin
• points: "all" — shows every data point as a jittered dot
• meanline: %{visible: true} — draws a line at the mean
• jitter — spreads the overlay points horizontally
• pointpos — shifts the point cloud left or right of the violin centre

Each trace is given an explicit x array so each violin sits at its own categorical x position. pointpos: -1.0 shifts dots to the left of the violin centre without overflowing into the neighbouring violin — ±1.8 is only safe for a single isolated violin; for adjacent violins the shift lands the dots inside the neighbouring body. xaxis: range is extended slightly so the leftmost violin's (Kale) dots don't clip at the axis boundary.

alias Plotly.{Figure, Violin}

:rand.seed(:exsss, {1, 2, 3})

gen = fn n, shift ->
  for _ <- 1..n do
    (for _ <- 1..12, do: :rand.uniform()) |> Enum.sum() |> Kernel.-(6.0 - shift)
  end
end

n = 60

Figure.new()
|> Figure.add_trace(
  Violin.new(
    x: List.duplicate("Kale", n),
    y: gen.(n, 0.0),
    name: "Kale",
    box: %{visible: true},
    meanline: %{visible: true},
    points: "all",
    jitter: 0.05,
    pointpos: -1.0,
    line: %{color: "green"},
    marker: %{color: "green", size: 4}
  )
)
|> Figure.add_trace(
  Violin.new(
    x: List.duplicate("Radishes", n),
    y: gen.(n, 0.5),
    name: "Radishes",
    box: %{visible: true},
    meanline: %{visible: true},
    points: "all",
    jitter: 0.05,
    pointpos: -1.0,
    line: %{color: "red"},
    marker: %{color: "red", size: 4}
  )
)
|> Figure.add_trace(
  Violin.new(
    x: List.duplicate("Carrots", n),
    y: gen.(n, 1.0),
    name: "Carrots",
    box: %{visible: true},
    meanline: %{visible: true},
    points: "all",
    jitter: 0.05,
    pointpos: -1.0,
    line: %{color: "orange"},
    marker: %{color: "orange", size: 4}
  )
)
|> Figure.update_layout(
  title: "Advanced Violin Plot",
  xaxis: %{range: [-0.8, 2.5]}
)
|> Plotly.show()