README.md

clipper2

A path/polygon clipping and offsetting library for Rust.

The focus of this crate is to provide an easy to use API, staying as close to the core Vec and fn types as possible.

The create uses the clipper2c-sys crate that in turn is a Rust wrapper around the C++ version of Clipper2.

Example

The below example uses macroquad to visualize the result of the operations and some helpers from the examples/ directory. See the examples directory for more examples.

use clipper2::*;
use helpers::{circle_path, draw_paths};
use macroquad::prelude::*;

mod helpers;

#[macroquad::main("Difference and inflate")]
async fn main() -> Result<(), ClipperError> {
    let circle = circle_path((5.0, 5.0), 3.0, 32);
    let circle2 = circle_path((7.0, 7.0), 1.0, 32);
    let rectangle = vec![(0.0, 0.0), (5.0, 0.0), (5.0, 6.0), (0.0, 6.0)];

    let result = circle
        .to_clipper_subject()
        .add_clip(circle2)
        .add_clip(rectangle)
        .difference(FillRule::default())?;

    let result2 = result
        .inflate(1.0, JoinType::Round, EndType::Polygon, 0.0)
        .simplify(0.01, false);

    loop {
        clear_background(BLACK);
        draw_paths(&result, SKYBLUE);
        draw_paths(&result2, GREEN);
        next_frame().await
    }
}

This is how the resulting shapes looks:

API uses f64, but i64 under the hood

The Clipper2 library is using i64 values to guarantee the robustness of all calculations. The C++ library exposes both int64_t/i64 and double/f64 versions of several types. This crate therefore internally uses the int64_t/i64 types only, but for now only exposes an f64 API.

The types Point, Path, and Paths therefore offers a PointScaler trait and generic parameter that allows the user to choose the scaling is used when it interally converts from f64 to i64. By default it uses the Centi struct that will scale the values by 100.

Early days

This project is in a super early stage and has for now only opened up a small part of what the C++ Clipper2 library has to offer. Expect breaking changes now and then for some more time to come as we find and explore more eregonomic ways of exposing the API in a Rust ideomatic way.

Please also feel free to come with suggestions on how the API can be simplified or send code contributions directly. See CONTRIBUTING.md for more details.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Serde by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.