pub fn draw_hollow_polygon<I>(
    image: &mut I,
    poly: &[Point<f32>],
    color: I::Pixel,
) -> Image<I::Pixel>
where
    I: GenericImage,
{
    let mut out = Image::new(image.width(), image.height());
    out.copy_from(image, 0, 0).unwrap();
    draw_hollow_polygon_mut(&mut out, poly, color);
    out
}
Draws the outline of a polygon on an image in place.

Draws as much of the outline of the polygon as lies within image bounds. The provided
list of points should be in polygon order and can be an open or closed path, i.e. if
the first and last points are not equal, the path will be closed anyway.
The edges of the polygon will be drawn in the order that they are provided, and an
implicit edge will be added from the last to the first point if they are not equal.
src/drawing/polygon.rs