# `Curves.Polyline.Curve`
[🔗](https://github.com/greetingsfellowhumans/curves/blob/main/lib/curves/polyline/curve.ex#L1)

Struct representing a polyline: knots joined by straight lines, like SVG's `<polyline>`.

```elixir
curve = Curves.define_polyline([{0, 0}, {2, 3}, {4, 1}, {6, 4}, {8, 2}])

# Find any point along it (u goes from 0.0 to Curves.max_u(curve))...
Curves.solve!(curve, 1.5)

# ...or draw it as an SVG image
Curves.Svg.save!(curve, "polyline.svg")
```

![Polyline](https://github.com/greetingsfellowhumans/curves/raw/main/assets/examples/polyline.svg)

Like a spline, it is solved with `u`: each straight line (segment) adds one to it, so `u = 1.0` is the
second knot and `Curves.max_u/1` is the last one. Within a segment the speed is steady, so `u = 1.5`
is exactly halfway between the second and third knots.

# `t`

```elixir
@opaque t()
```

A polyline. Its fields are internal and may change in any 1.x release,
so use the functions in `Curves` (e.g. `Curves.solve/3`, `Curves.max_u/1`) instead of reading them.

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*Consult [api-reference.md](api-reference.md) for complete listing*