https://github.com/micycle1/clipper2-java
Java port of Clipper2, a Polygon Clipping and Offsetting Library
https://github.com/micycle1/clipper2-java
clipper geometry offsetting polygon polygon-clipping
Last synced: 21 days ago
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Java port of Clipper2, a Polygon Clipping and Offsetting Library
- Host: GitHub
- URL: https://github.com/micycle1/clipper2-java
- Owner: micycle1
- Created: 2022-09-12T12:18:23.000Z (over 2 years ago)
- Default Branch: master
- Last Pushed: 2025-04-18T02:17:57.000Z (about 1 month ago)
- Last Synced: 2025-04-18T13:27:47.884Z (about 1 month ago)
- Topics: clipper, geometry, offsetting, polygon, polygon-clipping
- Language: Java
- Homepage: http://www.angusj.com/clipper2/Docs/Overview.htm
- Size: 590 KB
- Stars: 33
- Watchers: 5
- Forks: 14
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
[](https://jitpack.io/#micycle1/Clipper2-java)
# Clipper2-java
A Java port of _[Clipper2](https://github.com/AngusJohnson/Clipper2)_, an open source freeware software library that performs line and polygon clipping, and offsetting.
## Usage
### Overview
The interface of *Clipper2-java* is identical to the original C# version.
The `Clipper` class provides static methods for clipping, path-offsetting, minkowski-sums and path simplification.
For more complex clipping operations (e.g. when clipping open paths or when outputs are expected to include polygons nested within holes of others), use the `Clipper64` or `ClipperD` classes directly.
### Maven
*Clipper2-java* is available as Maven/Gradle artifact via [Jitpack](https://jitpack.io/#micycle1/Clipper2-java).
### Example
```java
Paths64 subj = new Paths64();
Paths64 clip = new Paths64();
subj.add(Clipper.MakePath(new int[] { 100, 50, 10, 79, 65, 2, 65, 98, 10, 21 }));
clip.add(Clipper.MakePath(new int[] { 98, 63, 4, 68, 77, 8, 52, 100, 19, 12 }));
Paths64 solution = Clipper.Union(subj, clip, FillRule.NonZero);
solution.get(0).forEach(p -> System.out.println(p.toString()));
```
## Port Info
* _tangiblesoftwaresolutions_' C# to Java Converter did the heavy lifting (but then a lot of manual work was required).
* Wrapper objects are used to replicate C# `ref` (pass-by-reference) behaviour. This isn't very Java-esque but avoids an unmanageable refactoring effort.
* Code passes all tests: polygon, line and polytree.
* Uses lower-case (x, y) for point coordinates.
* Private local variables have been renamed to their _camelCase_ variant but public methods (i.e. those of `Clipper.class`) retain their C# _PascalCase_ names (for now...).
* Benchmarks can be run by including `jmh:benchmark` to the chosen maven goal.
* `scanlineList` from `ClipperBase` uses Java `TreeSet` (variable renamed to `scanlineSet`).
## Benchmark
_lightbringer's_ Java [port](https://github.com/lightbringer/clipper-java) of Clipper1 is benchmarked against this project in the benchmarks. *Clipper2-java* is faster, which becomes more pronounced input size grows.
```
Benchmark (edgeCount) Mode Cnt Score Error Units
Clipper1.Intersection 1000 avgt 2 0.209 s/op
Clipper1.Intersection 2000 avgt 2 1.123 s/op
Clipper1.Intersection 4000 avgt 2 9.691 s/op
Clipper2.Intersection 1000 avgt 2 0.130 s/op
Clipper2.Intersection 2000 avgt 2 0.852 s/op
Clipper2.Intersection 4000 avgt 2 3.465 s/op
```