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https://github.com/tirithen/clipper2

A polygon Clipping and Offsetting library for Rust.
https://github.com/tirithen/clipper2

2d-graphics algorithm algorithms boolean cnc game-development geometry geospatial gis offsetting path-tracing rust

Last synced: 3 months ago
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A polygon Clipping and Offsetting library for Rust.

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README 

        
# clipper2



[![crate.io](https://img.shields.io/crates/v/clipper2.svg)](https://crates.io/crates/clipper2)

[![docs.rs](https://docs.rs/clipper2/badge.svg)](https://docs.rs/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](https://crates.io/crates/clipper2c-sys)

crate that in turn is a Rust wrapper around the C++ version of

[Clipper2](https://github.com/AngusJohnson/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.



```rust

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:



![Image displaying the result of the difference and inflate example](https://raw.githubusercontent.com/tirithen/clipper2/main/doc-assets/difference-and-inflate.png)



## API uses f64, but i64 under the hood



The Clipper2 library is [using `i64` values](https://www.angusj.com/clipper2/Docs/Robustness.htm)

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](https://github.com/tirithen/clipper2/blob/main/CONTRIBUTING.md)

for more details.



## License



Licensed under either of [Apache License, Version 2.0](https://github.com/tirithen/clipper2/blob/main/LICENSE-APACHE.md)

or [MIT license](https://github.com/tirithen/clipper2/blob/main/LICENSE-MIT.md)

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.