Adding Labels to Shapes

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

Section

Add a label map to any shape to annotate it directly. Key fields: text, font (map with size, color), textposition (e.g. "middle center", "top left"). The label moves with the shape.

alias Plotly.{Figure, Scatter}

Figure.new()
|> Figure.add_trace(Scatter.new(x: [1, 2, 3, 4, 5], y: [2, 4, 3, 5, 4], mode: "lines"))
|> Figure.update_layout(
  title: "Shapes with Labels",
  shapes: [
    %{
      type: "rect",
      xref: "x",
      yref: "y",
      x0: 1.5,
      y0: 2.5,
      x1: 2.5,
      y1: 4.5,
      fillcolor: "rgba(255, 165, 0, 0.3)",
      line: %{color: "orange"},
      label: %{
        text: "Region A",
        font: %{size: 14, color: "darkorange"},
        textposition: "middle center"
      }
    },
    %{
      type: "line",
      xref: "x",
      yref: "y",
      x0: 3.5,
      y0: 2,
      x1: 3.5,
      y1: 5,
      line: %{color: "royalblue", width: 2, dash: "dot"},
      label: %{
        text: "Threshold",
        font: %{size: 12, color: "royalblue"},
        textposition: "end"
      }
    }
  ]
)
|> Plotly.show()