iShape-Rust / iOverlay

Boolean Operations for 2D Polygons: Supports intersection, union, difference, xor, and self-intersections for all polygon varieties.

iOverlay

The iOverlay is a fast poly-bool library supporting main operations like union, intersection, difference, and xor, governed by either the even-odd or non-zero rule. This algorithm is based on Vatti clipping ideas but is an original implementation.

Documentation

Try out iOverlay with an interactive demo:

• Stars Rotation
• Shapes Editor

Features

• Operations: union, intersection, difference, and exclusion.
• Polygons: with holes, self-intersections, and multiple paths.
• Simplification: removes degenerate vertices and merges collinear edges.
• Fill Rules: even-odd and non-zero.

Getting Started

Add the following to your Cargo.toml:

[dependencies]
i_float
i_shape
i_overlay

Hello world

Let's union two squares

let mut overlay = Overlay::new(1);

let subj = [
    FixVec::new_number(-10, -10),
    FixVec::new_number(-10, 10),
    FixVec::new_number(10, 10),
    FixVec::new_number(10, -10),
];

let clip = [
    FixVec::new_number(-5, -5),
    FixVec::new_number(-5, 15),
    FixVec::new_number(15, 15),
    FixVec::new_number(15, -5),
];

overlay.add_path(&subj.to_vec(), ShapeType::Subject);
overlay.add_path(&clip.to_vec(), ShapeType::Clip);
let graph = overlay.build_graph(FillRule::NonZero);

let shapes = graph.extract_shapes(OverlayRule::Union);

println!("shapes count: {}", shapes.len());

if shapes.len() > 0 {
    let contour = shapes[0].contour();
    println!("shape 0 contour: ");
    for p in contour {
        let x = p.x.f32();
        let y = p.x.f32();
        println!("({}, {})", x, y);
    }
}

Overlay Rules

Union, A or B

Intersection, A and B

Difference, B - A

Exclusion, A xor B