ClipperLua

Clipper - The Clipper library performs clipping, offsetting and triangulation for polygons. All four boolean clipping operations are supported - intersection, union, difference and exclusive-or.

Polygons can be of any shape including self-intersecting polygons. The library is based on Vatti's clipping algorithm and runs on beta version 10.0 which is a significant rewrite of previous versions and it's improved in terms of performance.

The repository contains the compiled dll library supporting both 32 and 64-bit Windows OS and uses FFI binding solution to work with LuaJIT (Just-In-Time) programming language.

You can find more details in the official page: http://www.angusj.com/delphi/clipper/documentation/Docs/Overview/_Body.htm

Demonstration

> White color - subject polygon
> Blue color - clip polygon
> Green color - solution (even-odd intersection operation)
> Yellow color - offset solution (round type, delta = 15)
> Red color - inner triangulation of solution

Performance

Time (secs) to intersect 2 complex polygons - a subject and a clip
polygon - having random coordinates and varying numbers of vertices.

No. vertices	Clipper v10.0	Clipper v6.4.2
50	0.001s	0.001s
100	0.002s	0.003s
200	0.009s	0.019s
500	0.058s	0.084s
1000	0.255s	0.5s
1500	0.8s	1.87s
2000	2.05s	4.8s

API

1. Point:
+ void. New(number x, number y)
+ number: InPolygon(Path path)

2. Path:
+ void. New()
+ Point: Get(number i)
+ void: Add(Point pt)
+ number: Size()
+ number: Area()
+ bool: Orientation()
+ void: Reverse()
+ Paths: Simplify(number fillRule = FillRule.EvenOdd)

3. Paths:
+ void. New()
+ Path: Get(number i)
+ void: Add(Path path)
+ number: Size()
+ void: Reverse()
+ Paths: Simplify(number fillRule = FillRule.EvenOdd)
+ Paths: Offset(number delta, number joinType = JoinType.Round, number endType =
	EndType.Polygon, number miterLimit = 2.0, number arcTolerance = 0.0)
+ Paths: Triangulate(number fillRule = FillRule.EvenOdd)

4. Clipper:
+ void. New()
+ void: AddPath(Path path, number pathType, bool open = false)
+ void: AddPaths(Paths paths, number pathType, bool open = false)
+ Paths: Execute(number clipType = ClipType.Intersection,
	number fillRule = FillRule.EvenOdd)

5. ClipperOffset:
+ void. New(number miterLimit = 2.0, number arcTolerance = 0.0)
+ void: AddPath(Path path, number joinType =
	JoinType.Round, number endType = EndType.Polygon)
+ void: AddPaths(Paths path, number joinType =
	JoinType.Round, number endType = EndType.Polygon)
+ Paths: Execute(number delta)

6. ClipperTri:
+ void. New()
+ void: AddPath(Path path)
+ void: AddPaths(Paths paths)
+ Paths: Execute(number fillRule = FillRule.EvenOdd)