Customizing the Figure with Shapes and Annotations

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"},
  {:req, "~> 0.5"}
])

Section

layout.shapes and layout.annotations work on OHLC charts exactly as on scatter plots. A rect shape with xref: "x" and yref: "paper" highlights a date range across the full chart height. Pair with an annotation to label the event.

alias Plotly.{Figure, Ohlc}

csv =
  Req.get!("https://raw.githubusercontent.com/plotly/datasets/master/finance-charts-apple.csv").body

[header | rows] = String.split(csv, "\n", trim: true)
headers = String.split(header, ",")

parsed =
  Enum.map(rows, fn row -> Enum.zip(headers, String.split(row, ",")) |> Map.new() end)

dates = Enum.map(parsed, & &1["Date"])
open  = Enum.map(parsed, &(elem(Float.parse(&1["AAPL.Open"]), 0)))
high  = Enum.map(parsed, &(elem(Float.parse(&1["AAPL.High"]), 0)))
low   = Enum.map(parsed, &(elem(Float.parse(&1["AAPL.Low"]), 0)))
close = Enum.map(parsed, &(elem(Float.parse(&1["AAPL.Close"]), 0)))

Figure.new()
|> Figure.add_trace(Ohlc.new(x: dates, open: open, high: high, low: low, close: close))
|> Figure.update_layout(
  title: "Apple OHLC — Shapes & Annotations",
  showlegend: false,
  xaxis: %{type: "date", rangeslider: %{visible: false}},
  shapes: [
    %{
      type: "rect",
      xref: "x", yref: "paper",
      x0: "2016-01-01", y0: 0,
      x1: "2016-02-01", y1: 1,
      fillcolor: "#d3d3d3",
      opacity: 0.3,
      line: %{width: 0}
    }
  ],
  annotations: [
    %{
      x: "2016-01-15",
      y: 0.95,
      xref: "x", yref: "paper",
      text: "Jan 2016 drop",
      font: %{color: "darkblue"},
      showarrow: true,
      ax: 0, ay: -30
    }
  ]
)
|> Plotly.show()