Customizing Individual Bar Base

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

Section

base: sets the starting point (base) of each bar. By default bars start at 0. Setting base to a list makes each bar start at a different y value, creating floating or waterfall-like bars.

alias Plotly.{Figure, Bar}

Figure.new()
|> Figure.add_trace(
  Bar.new(
    x: ["2016", "2017", "2018", "2019", "2020"],
    y: [500, 600, 700, 1000, 900],
    base: [-500, -600, -700, -1000, -900],
    marker: %{color: "red"},
    name: "Expenses"
  )
)
|> Figure.add_trace(
  Bar.new(
    x: ["2016", "2017", "2018", "2019", "2020"],
    y: [300, 400, 500, 700, 600],
    base: 0,
    marker: %{color: "blue"},
    name: "Revenue"
  )
)
|> Figure.update_layout(title: "Bar Chart with Custom Base")
|> Plotly.show()