#import "@preview/cetz:0.3.1"
#import "handout.typ": *

// Shorthand, we'll be using these a lot.
#let tp = sym.plus.circle
#let tm = sym.times.circle

#let graphgrid(inner_content) = {
  align(
    center,
    box(
      inset: 3mm,
      cetz.canvas({
        import cetz.draw: *
        let x = 5.25

        grid(
          (0, 0), (x, x), step: 0.75,
          stroke: luma(100) + 0.3mm
        )

        if (inner_content != none) {
          inner_content
        }

        mark((0, x + 0.5), (0, x + 1), symbol: ">", fill: black, scale: 1)
        mark((x + 0.5, 0), (x + 1, 0), symbol: ">", fill: black, scale: 1)

        line(
          (0, x + 0.25),
          (0, 0),
          (x + 0.25, 0),
          stroke: 0.75mm + black,
        )
      }),
    ),
  )
}

/// Adds extra padding to an equation.
/// Used as follows:
///
/// #eqmbox($
///   f(x) = -2(x #tp 2)(x #tp 8)
/// $)
///
/// Note that there are newlines between the $ and content,
/// this gives us display math (which is what we want when using this macro)
#let eqnbox(eqn) = {
  align(
    center,
    box(
      inset: 3mm,
      eqn,
    ),
  )
}

#let dotline(a, b) = {
  cetz.draw.line(
    a,
    b,
    stroke: (
      dash: "dashed",
      thickness: 0.5mm,
      paint: ored,
    ),
  )
}