Function contour_to_path 

pub fn contour_to_path<T, C: PointCoord>(
    points: &[T],
    to_point: impl Fn(&T) -> (Point<C>, PointFlags),
    start: PathContourStart,
    sink: &mut impl PathSink,
) -> bool

Converts one contour into path commands, taking its points from a slice of anything to_point can read them out of.

For outlines held in some shape other than parallel point and flag arrays — an autohinter’s points, say, which carry more per point than these do.

Returns false on the same terms as outline_to_path, and leaves what it drew on the sink.

use read_fonts::{
    model::glyph::outline::SvgSink,
    tables::glyf::{outline::{contour_to_path, PathContourStart}, PointFlags},
    types::Point,
};

// Whatever the caller happens to hold, so long as points can be read out.
struct MyPoint { x: f32, y: f32, on_curve: bool, _more: [u32; 8] }

let contour = [
    MyPoint { x: 0.0, y: 0.0, on_curve: true, _more: [0; 8] },
    MyPoint { x: 8.0, y: 0.0, on_curve: true, _more: [0; 8] },
    MyPoint { x: 8.0, y: 8.0, on_curve: true, _more: [0; 8] },
];

let mut pen = SvgSink::with_precision(1);
assert!(contour_to_path(
    &contour,
    |p| {
        let flags = if p.on_curve {
            PointFlags::on_curve()
        } else {
            PointFlags::off_curve_quad()
        };
        (Point::new(p.x, p.y), flags)
    },
    PathContourStart::ScanBackward,
    &mut pen,
));
assert_eq!(pen.as_ref(), "M0.0,0.0 L8.0,0.0 L8.0,8.0 Z");