Style Waterfall Chart

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

Section

decreasing:, increasing:, and totals: maps each accept a marker: field with color: and line: for per-type bar styling. layout.waterfallgap: sets the gap fraction between bars (0–1). This allows full visual differentiation between positive, negative, and summary bars without needing to style each bar individually.

alias Plotly.{Figure, Waterfall}

Figure.new()
|> Figure.add_trace(
  Waterfall.new(
    x: [
      ["2016", "2017", "2017", "2017", "2017", "2018", "2018", "2018", "2018"],
      ["initial", "q1", "q2", "q3", "total", "q1", "q2", "q3", "total"]
    ],
    measure: [
      "absolute",
      "relative",
      "relative",
      "relative",
      "total",
      "relative",
      "relative",
      "relative",
      "total"
    ],
    y: [10, 20, 30, -10, nil, 10, 20, -40, nil],
    base: 300,
    decreasing: %{marker: %{color: "Maroon", line: %{color: "red", width: 2}}},
    increasing: %{marker: %{color: "Teal"}},
    totals: %{marker: %{color: "deep sky blue", line: %{color: "blue", width: 3}}}
  )
)
|> Figure.update_layout(
  title: "Profit and Loss Statement",
  waterfallgap: 0.3,
  xaxis: %{tickfont: %{size: 15}, ticks: "outside"}
)
|> Plotly.show()