hypercurve 0.2.0

Hyperreal-backed planar curves, contours, and regions for CAD topology
Documentation 
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use hypercurve::{
    BulgeVertex2, Contour2, CurveError, CurveString2, FillRule, Point2,
    PolylineReconstructionOptions, Real, Segment2,
};

fn r(value: f64) -> Real {
    Real::try_from(value).unwrap()
}

fn p(x: f64, y: f64) -> Point2 {
    Point2::new(r(x), r(y))
}

fn assert_close(actual: f64, expected: f64) {
    let tolerance = 1e-8_f64.max(expected.abs() * 1e-8);
    assert!(
        (actual - expected).abs() <= tolerance,
        "expected {actual} to be within {tolerance} of {expected}"
    );
}

#[test]
fn reconstruction_merges_collinear_polyline_to_one_line() {
    let points = [p(0.0, 0.0), p(1.0, 0.0), p(2.0, 0.0), p(3.0, 0.0)];

    let curve =
        CurveString2::reconstruct_from_polyline(&points, PolylineReconstructionOptions::default())
            .unwrap();

    assert_eq!(curve.len(), 1);
    let Segment2::Line(line) = &curve.segments()[0] else {
        panic!("collinear samples should reconstruct as one line");
    };
    assert_eq!(line.start(), &points[0]);
    assert_eq!(line.end(), &points[3]);
}

#[test]
fn reconstruction_keeps_single_corner_as_two_lines_by_default() {
    let points = [p(0.0, 0.0), p(1.0, 0.0), p(1.0, 1.0)];

    let curve =
        CurveString2::reconstruct_from_polyline(&points, PolylineReconstructionOptions::default())
            .unwrap();

    assert_eq!(curve.len(), 2);
    assert!(
        curve
            .segments()
            .iter()
            .all(|segment| matches!(segment, Segment2::Line(_)))
    );
}

#[test]
fn reconstruction_promotes_consistent_semicircle_samples_to_arc() {
    let root_half = 0.5_f64.sqrt();
    let points = [
        p(0.0, 0.0),
        p(1.0 - root_half, -root_half),
        p(1.0, -1.0),
        p(1.0 + root_half, -root_half),
        p(2.0, 0.0),
    ];
    let options = PolylineReconstructionOptions {
        min_arc_points: 3,
        distance_tolerance: 1e-8,
        ..PolylineReconstructionOptions::default()
    };

    let curve = CurveString2::reconstruct_from_polyline(&points, options).unwrap();

    assert_eq!(curve.len(), 1);
    let Segment2::Arc(arc) = &curve.segments()[0] else {
        panic!("constant-curvature samples should reconstruct as one arc");
    };
    assert_eq!(arc.start(), &points[0]);
    assert_eq!(arc.end(), &points[4]);
    assert_close(arc.bulge().unwrap().to_f64_approx().unwrap(), 1.0);
    assert_close(arc.center().x().to_f64_approx().unwrap(), 1.0);
    assert_close(arc.center().y().to_f64_approx().unwrap(), 0.0);
}

#[test]
fn reconstruction_splits_arcs_at_semicircle_boundary() {
    let points = [
        p(1.0, 0.0),
        p(0.0, -1.0),
        p(-1.0, 0.0),
        p(0.0, 1.0),
        p(1.0, 0.0),
    ];
    let options = PolylineReconstructionOptions {
        min_arc_points: 3,
        ..PolylineReconstructionOptions::default()
    };

    let curve = CurveString2::reconstruct_from_polyline(&points, options).unwrap();

    assert_eq!(curve.len(), 2);
    assert!(
        curve
            .segments()
            .iter()
            .all(|segment| matches!(segment, Segment2::Arc(_)))
    );
}

#[test]
fn reconstruction_accepts_closed_polyline_without_repeated_first_point() {
    let points = [p(0.0, 0.0), p(4.0, 0.0), p(4.0, 3.0), p(0.0, 3.0)];

    let contour = Contour2::reconstruct_from_closed_polyline(
        &points,
        PolylineReconstructionOptions::default(),
    )
    .unwrap();

    assert_eq!(contour.len(), 4);
    assert_eq!(contour.fill_rule(), FillRule::NonZero);
    assert!(
        contour
            .segments()
            .iter()
            .all(|segment| matches!(segment, Segment2::Line(_)))
    );
}

#[test]
fn reconstruction_accepts_closed_polyline_with_repeated_first_point() {
    let points = [
        p(0.0, 0.0),
        p(4.0, 0.0),
        p(4.0, 3.0),
        p(0.0, 3.0),
        p(0.0, 0.0),
    ];

    let contour = Contour2::reconstruct_from_closed_polyline_with_fill_rule(
        &points,
        PolylineReconstructionOptions::default(),
        FillRule::EvenOdd,
    )
    .unwrap();

    assert_eq!(contour.len(), 4);
    assert_eq!(contour.fill_rule(), FillRule::EvenOdd);
}

#[test]
fn reconstruction_removes_adjacent_duplicate_samples() {
    let points = [p(0.0, 0.0), p(0.0, 0.0), p(1.0, 0.0), p(2.0, 0.0)];

    let vertices =
        BulgeVertex2::reconstruct_polyline(&points, PolylineReconstructionOptions::default())
            .unwrap();

    assert_eq!(vertices.len(), 2);
    assert_eq!(vertices[0].point(), &points[0]);
    assert_eq!(vertices[1].point(), &points[3]);
}

#[test]
fn reconstruction_rejects_invalid_options() {
    let points = [p(0.0, 0.0), p(1.0, 0.0)];
    let options = PolylineReconstructionOptions {
        min_arc_points: 2,
        ..PolylineReconstructionOptions::default()
    };

    let err = CurveString2::reconstruct_from_polyline(&points, options)
        .expect_err("min_arc_points below three is invalid");
    assert_eq!(err, CurveError::InvalidReconstructionOptions);
}