line.typ

#import "@preview/cetz:0.3.1": canvas, draw
#import "@preview/cetz-plot:0.1.0": plot

#set page(width: auto, height: auto, margin: .5cm)

#let style = (stroke: black, fill: rgb(0, 0, 200, 75))

#let f1(x) = calc.sin(x)
#let fn = (
  ($ x - x^3"/"3! $, x => x - calc.pow(x, 3)/6),
  ($ x - x^3"/"3! - x^5"/"5! $, x => x - calc.pow(x, 3)/6 + calc.pow(x, 5)/120),
  ($ x - x^3"/"3! - x^5"/"5! - x^7"/"7! $, x => x - calc.pow(x, 3)/6 + calc.pow(x, 5)/120 - calc.pow(x, 7)/5040),
)

#set text(size: 10pt)

#canvas({
  import draw: *

  // Set-up a thin axis style
  set-style(axes: (stroke: .5pt, tick: (stroke: .5pt)),
            legend: (stroke: none, orientation: ttb, item: (spacing: .3), scale: 80%))

  plot.plot(size: (12, 8),
    x-tick-step: calc.pi/2,
    x-format: plot.formats.multiple-of,
    y-tick-step: 2, y-min: -2.5, y-max: 2.5,
    legend: "inner-north",
    {
      let domain = (-1.1 * calc.pi, +1.1 * calc.pi)

      for ((title, f)) in fn {
        plot.add-fill-between(f, f1, domain: domain,
          style: (stroke: none), label: title)
      }
      plot.add(f1, domain: domain, label: $ sin x  $,
        style: (stroke: black))
    })
})