README.md

Go Clipper2

A high-performance pure Go port of Clipper2, the industry-standard polygon clipping and offsetting library. Go Clipper2 provides robust geometric operations with 64-bit integer precision, eliminating floating-point numerical errors common in computational geometry.

🌟 Features

• 🚀 Pure Go Implementation: Zero C/C++ dependencies for production use
• 🎯 Complete API: All Clipper2 operations including boolean ops, offsetting, and clipping
• 🧪 Comprehensive Testing: Property-based testing with different cases
• 📦 Easy Integration: Simple Go module with clean, idiomatic API

Prerequisites

• Go 1.23 or later

Installation

go get github.com/bolom009/go-clipper2

📖 Usage Examples

Basic Boolean Operations

package main

import (
    "fmt"
    goclipper2 "github.com/bolom009/go-clipper2"
)

func main() {
    // Define two overlapping rectangles
	var (
		subject = goclipper2.Paths64{
			{{0, 0}, {100, 0}, {100, 100}, {0, 100}},
		}
		clip = goclipper2.Paths64{
			{{50, 50}, {150, 50}, {150, 150}, {50, 150}},
		}
	)

	// wrapped method booleanOp (simplify usage of lib)
	unionResults := goclipper2.UnionWithClipPaths64(subject, clip, goclipper2.NonZero)
	fmt.Printf("Union area: %v\n", unionResults)
	
	// booleanOp
	unionResults = goclipper2.BooleanOpPaths64(goclipper2.Union, subject, clip, goclipper2.NonZero)
    fmt.Printf("Union area: %v\n", unionResults)
	
	/*
	    goclipper2.UnionPaths64(...)
	    goclipper2.UnionWithClipPaths64(...)
	    goclipper2.IntersectWithClipPaths64(...)
	    goclipper2.DifferenceWithClipPaths64(...)
	    goclipper2.XorWithClipPaths64(...)
	    goclipper2.UnionWithClipPathsD(...)
	    ...
	*/
}

📊 Implementation Status

Feature	Status
Boolean Operations {64,D}	✅
Union64, UnionD	✅
Intersect64, IntersectD	✅
Difference64, DifferenceD	✅
Xor64, XorD	✅
Polygon Offsetting	✅
Rectangle Clipping	✅
Area Calculation	✅
Orientation Detection	✅
Path Reversal	✅
Minkowski Operations	✅
PolyTree, PolyPath {64, D}	✅
ZCallback	❌

Legend: ✅ Implemented, ❌ Not implemented, 🚧 In progress

Performance Tips

• Use integer coordinates when possible (more robust than float64)
• For simple rectangular clipping, use RectClip64 instead of boolean operations
• Pre-simplify complex polygons before operations
• Consider polygon orientation for optimal performance

📄 License

This project is licensed under the Boost Software License 1.0, the same as the original Clipper2 library. See LICENSE for details.