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.
Try out iOverlay with an interactive demo:
- 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.
Add the following to your Cargo.toml:
[dependencies]
i_overlay = "^1.3"
Let's union two squares
let subj = [
F64Point::new(-10.0, -10.0),
F64Point::new(-10.0, 10.0),
F64Point::new(10.0, 10.0),
F64Point::new(10.0, -10.0),
];
let clip = [
F64Point::new(-5.0, -5.0),
F64Point::new(-5.0, 15.0),
F64Point::new(15.0, 15.0),
F64Point::new(15.0, -5.0),
];
let mut overlay = FloatOverlay::new();
overlay.add_path(&subj, ShapeType::Subject);
overlay.add_path(&clip, 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][0];
println!("shape 0 contour: ");
for p in contour {
let x = p.x;
let y = p.y;
println!("({}, {})", x, y);
}
}
The output of the extract_shapes
function is a Vec<Vec<Vec<F64Point>>>
, where:
- The outer
Vec<F64Shape>
represents a set of shapes. - Each shape
Vec<F64Path>
represents a collection of paths, where the first path is the outer boundary, and all subsequent paths are holes in this boundary. - Each path
Vec<F64Point>
is a sequence of points, forming a closed path.
Note: Outer boundary paths have a clockwise order, and holes have a counterclockwise order.