go_clipper2

package module
v1.3.0 Latest Latest
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 Go to latest Published: Oct 28, 2025 License: BSL-1.0 Imports: 7 Imported by: 0

README

Go Clipper2

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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.

Documentation

Index

Constants

View Source 
const (
	ToEven = iota
	AwayFromZero
)
View Source 
const (
	None      VertexFlags = 0
	OpenStart             = 1
	OpenEnd               = 2
	LocalMax              = 4
	LocalMin              = 8
)
View Source 
const (
	MaxInt64 = int64(9223372036854775807)
	MaxCoord = MaxInt64 / 4

	Invalid64 = MaxInt64
)
View Source 
const (
	Tolerance float64 = 1.0e-12
)

Variables

View Source 
var (
	ErrPrecisionRange         = errors.New("precision is out of range")
	ErrInvalidRemoveListIndex = errors.New("invalid remove index from list")
)

Functions

func Area64 

func Area64(path Path64) float64

func AreaD 

func AreaD(path PathD) float64

func AreaPaths64 

func AreaPaths64(paths Paths64) float64

func AreaPathsD 

func AreaPathsD(paths PathsD) float64

func CrossProduct 

func CrossProduct(pt1, pt2, pt3 Point64) float64

CrossProduct for three Point64 (pt1->pt2 x pt2->pt3)

func IsOdd 

func IsOdd(val int) bool

func IsPositive64 

func IsPositive64(poly Path64) bool

func IsPositiveD 

func IsPositiveD(poly PathD) bool

func NewClipper64 

func NewClipper64() *clipper64

func NewClipperD 

func NewClipperD(decimalPrecision int) *clipperD

func Path2ContainsPath1 

func Path2ContainsPath1(path1, path2 Path64) bool

func PerpendicDistFromLineSqr64 

func PerpendicDistFromLineSqr64(pt, line1, line2 Point64) float64

func PerpendicDistFromLineSqrD 

func PerpendicDistFromLineSqrD(pt, line1, line2 PointD) float64

func PointsNearEqual 

func PointsNearEqual(pt1, pt2 PointD, distanceSqrd float64) bool

func ReversePath added in v1.0.1 

func ReversePath[T any](p []T) []T

func SwapFrontBackSides 

func SwapFrontBackSides(outrec *OutRec)

Types

type Active 

type Active struct {
	// contains filtered or unexported fields
}

type ClipType 

type ClipType uint8

ClipType specifies the type of boolean operation 

const (
	NoClip       ClipType = iota
	Intersection          // intersect subject and clip polygons
	Union                 // union (OR) subject and clip polygons
	Difference            // subtract clip polygons from subject polygons
	Xor                   // exclusively or (XOR) subject and clip polygons
)

type ClipperOffset 

type ClipperOffset struct {
	ArcTolerance      float64
	MergeGroups       bool
	MiterLimit        float64
	PreserveCollinear bool
	ReverseSolution   bool
	// contains filtered or unexported fields
}

func NewClipperOffset 

func NewClipperOffset(miterLimit, arcTolerance float64, preserveCollinear, reverseSolution bool) *ClipperOffset

func (*ClipperOffset) AddPaths 

func (co *ClipperOffset) AddPaths(paths Paths64, joinType JoinType, endType EndType)

func (*ClipperOffset) CalcSolutionCapacity 

func (co *ClipperOffset) CalcSolutionCapacity() int

func (*ClipperOffset) CheckPathsReversed 

func (co *ClipperOffset) CheckPathsReversed() bool

func (*ClipperOffset) Execute64 

func (co *ClipperOffset) Execute64(delta float64, solution *Paths64)

func (*ClipperOffset) SetDeltaCallback added in v1.3.0 

func (co *ClipperOffset) SetDeltaCallback(deltaCallback *DeltaCallbackFunc)

type DeltaCallbackFunc added in v1.3.0 

type DeltaCallbackFunc func(path *Path64, path_normals *PathD, curr_idx uint8, prev_idx uint8) float64

type EndType 

type EndType uint8
const (
	Polygon EndType = iota
	Joined
	Butt
	SquareET
	RoundET
)

type FillRule 

type FillRule uint8

FillRule specifies how to determine polygon interiors for self-intersecting polygons 

const (
	EvenOdd  FillRule = iota // odd numbered sub-regions are filled
	NonZero                  // non-zero sub-regions are filled
	Positive                 // positive sub-regions are filled
	Negative                 // negative sub-regions are filled
)

type Group 

type Group struct {
	// contains filtered or unexported fields
}

func NewGroup 

func NewGroup(paths Paths64, joinType JoinType, endTypeVal ...EndType) *Group

func (*Group) GetLowestPathInfo 

func (g *Group) GetLowestPathInfo() (int, bool)

type HorzJoin 

type HorzJoin struct {
	// contains filtered or unexported fields
}

func NewHorzJoin 

func NewHorzJoin(ltor *OutPt, rtol *OutPt) *HorzJoin

type HorzSegment 

type HorzSegment struct {
	// contains filtered or unexported fields
}

func NewHorzSegment 

func NewHorzSegment(op *OutPt) *HorzSegment

type InflateOption added in v1.2.1 

type InflateOption func(*inflateConfig)

func WithArcTolerance added in v1.2.1 

func WithArcTolerance(tolerance float64) InflateOption

func WithMitterLimit added in v1.2.1 

func WithMitterLimit(limit float64) InflateOption

func WithPrecision added in v1.2.1 

func WithPrecision(precision int) InflateOption

type IntersectNode 

type IntersectNode struct {
	// contains filtered or unexported fields
}

func NewIntersectNode 

func NewIntersectNode(pt Point64, edge1 *Active, edge2 *Active) *IntersectNode

type JoinType 

type JoinType uint8
const (
	Miter JoinType = iota
	Square
	Bevel
	Round
)

type JoinWith 

type JoinWith uint8
const (
	JoinNone JoinWith = iota
	JoinLeft
	JoinRight
)

type LocalMinima 

type LocalMinima struct {
	Vertex   *Vertex
	PolyType PathType
	IsOpen   bool
}

func NewLocalMinima 

func NewLocalMinima(vertex *Vertex, polytype PathType, isOpen bool) *LocalMinima

func (*LocalMinima) Equals 

func (l *LocalMinima) Equals(r *LocalMinima) bool

type Location added in v1.1.0 

type Location int8
const (
	Left Location = iota
	Top
	Right
	Bottom
	Inside
)

type MidpointRounding 

type MidpointRounding uint8

type OutPt 

type OutPt struct {
	// contains filtered or unexported fields
}

type OutPt2 added in v1.1.0 

type OutPt2 struct {
	// contains filtered or unexported fields
}

func NewOutPt2 added in v1.1.0 

func NewOutPt2(pt Point64) *OutPt2

type OutRec 

type OutRec struct {
	// contains filtered or unexported fields
}

type Path64 

type Path64 []Point64

Path64 represents a sequence of points forming a path

func Ellipse64 

func Ellipse64(center Point64, radiusX, radiusY float64, steps int) Path64

func MakePath64 added in v1.0.1 

func MakePath64(vals ...int64) Path64

func OffsetPath 

func OffsetPath(path Path64, dx, dy int64) Path64

func PathDToPath64 

func PathDToPath64(path PathD) Path64

func ScalePath64 

func ScalePath64(path Path64, scale float64) Path64

func ScalePathDToPath64 

func ScalePathDToPath64(path PathD, scale float64) Path64

func SimplifyPath64 added in v1.1.0 

func SimplifyPath64(path Path64, epsilon float64, isClosedPath bool) Path64

func StripDuplicates 

func StripDuplicates(path Path64, isClosedPath bool) Path64

func TranslatePath64 added in v1.1.0 

func TranslatePath64(path Path64, dx, dy int64) Path64

func TrimCollinear64 added in v1.1.0 

func TrimCollinear64(path Path64, isOpen bool) Path64

type PathD 

type PathD []PointD

PathD represents a sequence of points forming a path

func EllipseD 

func EllipseD(center PointD, radiusX, radiusY float64, steps int) PathD

func MakePathD added in v1.0.1 

func MakePathD(vals ...float64) PathD

func Path64ToPathD 

func Path64ToPathD(path Path64) PathD

func ScalePath64ToPathD 

func ScalePath64ToPathD(path Path64, scale float64) PathD

func ScalePathD 

func ScalePathD(path PathD, scale float64) PathD

func SimplifyPathD added in v1.1.0 

func SimplifyPathD(path PathD, epsilon float64, isClosedPath bool) PathD

func TranslatePathD added in v1.1.0 

func TranslatePathD(path PathD, dx, dy float64) PathD

func TrimCollinearD added in v1.1.0 

func TrimCollinearD(path PathD, precision int, isOpen bool) PathD

type PathType 

type PathType uint8
const (
	Subject PathType = iota
	Clip
)

type Paths64 

type Paths64 []Path64

Paths64 represents a collection of paths

func BooleanOpPaths64 

func BooleanOpPaths64(clipType ClipType, subject Paths64, clip Paths64, fillRule FillRule) Paths64

func DifferenceWithClipPaths64 

func DifferenceWithClipPaths64(subject, clip Paths64, fillRule FillRule) Paths64

func InflatePaths64 

func InflatePaths64(paths Paths64, delta float64, joinType JoinType, endType EndType, opts ...InflateOption) Paths64

func IntersectWithClipPaths64 

func IntersectWithClipPaths64(subject, clip Paths64, fillRule FillRule) Paths64

func MinkowskiDiff64 

func MinkowskiDiff64(pattern, path Path64, isClosed bool) Paths64

func MinkowskiSum64 

func MinkowskiSum64(pattern, path Path64, isClosed bool) Paths64

func PathsDToPaths64 

func PathsDToPaths64(path PathsD) Paths64

func RectClipLinesPath64 added in v1.1.0 

func RectClipLinesPath64(rect Rect64, path Path64) Paths64

func RectClipLinesPaths64 added in v1.1.0 

func RectClipLinesPaths64(rect Rect64, paths Paths64) Paths64

func RectClipPath64 added in v1.1.0 

func RectClipPath64(rect Rect64, path Path64) Paths64

func RectClipPaths64 added in v1.1.0 

func RectClipPaths64(rect Rect64, paths Paths64) Paths64

func ScalePathsDToPaths64 

func ScalePathsDToPaths64(paths PathsD, scale float64) Paths64

func SimplifyPaths64 added in v1.1.0 

func SimplifyPaths64(paths Paths64, epsilon float64, isClosedPaths bool) Paths64

func TranslatePaths64 added in v1.1.0 

func TranslatePaths64(paths Paths64, dx, dy int64) Paths64

func UnionPaths64 

func UnionPaths64(subject Paths64, fillRule FillRule) Paths64

func UnionWithClipPaths64 

func UnionWithClipPaths64(subject, clip Paths64, fillRule FillRule) Paths64

func XorWithClipPaths64 

func XorWithClipPaths64(subject, clip Paths64, fillRule FillRule) Paths64

type PathsD 

type PathsD []PathD

PathsD represents a collection of paths

func BooleanOpPathsD 

func BooleanOpPathsD(clipType ClipType, subject PathsD, clip PathsD, fillRule FillRule, precisionV ...int) PathsD

func DifferenceWithClipPathsD 

func DifferenceWithClipPathsD(subject, clip PathsD, fillRule FillRule, precision ...int) PathsD

func InflatePathsD 

func InflatePathsD(paths PathsD, delta float64, joinType JoinType, endType EndType, opts ...InflateOption) PathsD

func IntersectWithClipPathsD 

func IntersectWithClipPathsD(subject, clip PathsD, fillRule FillRule, precision ...int) PathsD

func MinkowskiDiffD 

func MinkowskiDiffD(pattern, path PathD, isClosed bool, precisionV ...int) PathsD

func MinkowskiSumD 

func MinkowskiSumD(pattern, path PathD, isClosed bool, precisionV ...int) PathsD

func Paths64ToPathsD 

func Paths64ToPathsD(path Paths64) PathsD

func RectClipLinesPathD added in v1.1.0 

func RectClipLinesPathD(rect RectD, path PathD) PathsD

func RectClipLinesPathsD added in v1.1.0 

func RectClipLinesPathsD(rect RectD, paths PathsD, precisionV ...int) PathsD

func RectClipPathD added in v1.1.0 

func RectClipPathD(rect RectD, path PathD) PathsD

func RectClipPathsD added in v1.1.0 

func RectClipPathsD(rect RectD, paths PathsD, precisionV ...int) PathsD

func ScalePaths64ToPathsD 

func ScalePaths64ToPathsD(paths Paths64, scale float64) PathsD

func SimplifyPathsD added in v1.1.0 

func SimplifyPathsD(paths PathsD, epsilon float64, isClosedPaths bool) PathsD

func TranslatePathsD added in v1.1.0 

func TranslatePathsD(paths PathsD, dx, dy float64) PathsD

func UnionPathsD 

func UnionPathsD(subject PathsD, fillRule FillRule, precision ...int) PathsD

func UnionWithClipPathsD 

func UnionWithClipPathsD(subject, clip PathsD, fillRule FillRule, precision ...int) PathsD

func XorWithClipPathsD 

func XorWithClipPathsD(subject, clip PathsD, fillRule FillRule, precision ...int) PathsD

type Point64 

type Point64 struct {
	X, Y int64
}

Point64 represents a point with 64-bit integer coordinates

func NewFloatPoint64 

func NewFloatPoint64(x, y float64) Point64

func (*Point64) Add 

func (p *Point64) Add(p2 Point64)

func (*Point64) Equals 

func (p *Point64) Equals(p2 Point64) bool

func (*Point64) NEquals 

func (p *Point64) NEquals(p2 Point64) bool

func (*Point64) Sub 

func (p *Point64) Sub(p2 Point64)

func (*Point64) ToPoint64 

func (p *Point64) ToPoint64(pt PointD) Point64

func (*Point64) ToPointD 

func (p *Point64) ToPointD() PointD

func (*Point64) ToPointDScale 

func (p *Point64) ToPointDScale(scale float64) PointD

type PointD 

type PointD struct {
	X, Y float64
}

func (*PointD) Equals 

func (p *PointD) Equals(p2 PointD) bool

func (*PointD) NEquals 

func (p *PointD) NEquals(p2 PointD) bool

func (*PointD) Negate 

func (p *PointD) Negate()

func (*PointD) Scale 

func (p *PointD) Scale(scale float64)

func (*PointD) ToPoint64 

func (p *PointD) ToPoint64() Point64

func (*PointD) ToPoint64Scale 

func (p *PointD) ToPoint64Scale(scale float64) Point64

type PointInPolygonResult 

type PointInPolygonResult uint8
const (
	IsOn PointInPolygonResult = iota
	IsInside
	IsOutside
)

func PointInPolygon added in v1.1.0 

func PointInPolygon(pt Point64, polygon Path64) PointInPolygonResult

type PolyPath64 added in v1.1.5 

type PolyPath64 struct {
	*PolyPathBase
}

type PolyPathBase 

type PolyPathBase struct {
	// contains filtered or unexported fields
}

func NewPolyPathBase 

func NewPolyPathBase(parent *PolyPathBase) *PolyPathBase

func (*PolyPathBase) AddChild 

func (p *PolyPathBase) AddChild(pth Path64) *PolyPathBase

func (*PolyPathBase) Clear 

func (p *PolyPathBase) Clear()

func (*PolyPathBase) Count added in v1.1.5 

func (p *PolyPathBase) Count() int

func (*PolyPathBase) GetChildren 

func (p *PolyPathBase) GetChildren() []*PolyPathBase

func (*PolyPathBase) IsHole 

func (p *PolyPathBase) IsHole() bool

func (*PolyPathBase) Level 

func (p *PolyPathBase) Level() int

func (*PolyPathBase) Scale added in v1.1.5 

func (p *PolyPathBase) Scale() float64

func (*PolyPathBase) SetScale added in v1.1.5 

func (p *PolyPathBase) SetScale(scale float64)

func (*PolyPathBase) ToString added in v1.1.5 

func (p *PolyPathBase) ToString() string

func (*PolyPathBase) ToStringInternal added in v1.1.5 

func (p *PolyPathBase) ToStringInternal(idx, level int) string

type PolyPathD added in v1.1.5 

type PolyPathD struct {
	*PolyPathBase
}

type PolyTree64 added in v1.1.5 

type PolyTree64 PolyPath64

func BooleanOpPolyTree64 added in v1.2.0 

func BooleanOpPolyTree64(clipType ClipType, subject Paths64, clip Paths64, fillRule FillRule) *PolyTree64

func NewPolyTree64 added in v1.1.5 

func NewPolyTree64() *PolyTree64

type PolyTreeD added in v1.1.5 

type PolyTreeD PolyPathD

func BooleanOpPolyTreeD added in v1.1.5 

func BooleanOpPolyTreeD(clipType ClipType, subject PathsD, clip PathsD, fillRule FillRule, precisionV ...int) *PolyTreeD

func NewPolyTreeD added in v1.1.5 

func NewPolyTreeD() *PolyTreeD

type Rect64 

type Rect64 struct {
	// contains filtered or unexported fields
}

func GetBounds64 

func GetBounds64(path Path64) Rect64

func NewRect64 

func NewRect64(left, top, right, bottom int64) Rect64

func NewRect64Invalid 

func NewRect64Invalid(isValid bool) Rect64

func ScaleRect64 

func ScaleRect64(rec Rect64, scale float64) Rect64

func ScaleRectD added in v1.1.0 

func ScaleRectD(rec RectD, scale float64) Rect64

func (*Rect64) AsPath 

func (r *Rect64) AsPath() Path64

func (*Rect64) Contains 

func (r *Rect64) Contains(rec Rect64) bool

func (*Rect64) Intersects 

func (r *Rect64) Intersects(rec Rect64) bool

func (*Rect64) IsEmpty 

func (r *Rect64) IsEmpty() bool

func (*Rect64) IsInvalid 

func (r *Rect64) IsInvalid() bool

func (*Rect64) MidPoint 

func (r *Rect64) MidPoint() Point64

type RectClip64 added in v1.1.0 

type RectClip64 struct {
	// contains filtered or unexported fields
}

func NewRectClip64 added in v1.1.0 

func NewRectClip64(rect Rect64, getPathV ...func(op *OutPt2) Path64) *RectClip64

func (*RectClip64) Execute added in v1.1.0 

func (r *RectClip64) Execute(paths Paths64) Paths64

type RectClipLines64 added in v1.1.0 

type RectClipLines64 struct {
	*RectClip64
}

func NewRectClipLines64 added in v1.1.0 

func NewRectClipLines64(rect Rect64) *RectClipLines64

type RectD 

type RectD struct {
	// contains filtered or unexported fields
}

func NewRectD 

func NewRectD(left, top, right, bottom float64) RectD

func NewRectDInvalid 

func NewRectDInvalid(isValid bool) RectD

func (*RectD) AsPath 

func (r *RectD) AsPath() PathD

func (*RectD) Contains 

func (r *RectD) Contains(rec RectD) bool

func (*RectD) Intersects 

func (r *RectD) Intersects(rec RectD) bool

func (*RectD) IsEmpty 

func (r *RectD) IsEmpty() bool

func (*RectD) IsInvalid 

func (r *RectD) IsInvalid() bool

func (*RectD) MidPoint 

func (r *RectD) MidPoint() PointD

type UInt128Struct 

type UInt128Struct struct {
	Lo64 uint64
	Hi64 uint64
}

type Vertex 

type Vertex struct {
	// contains filtered or unexported fields
}

func NewVertex 

func NewVertex(pt Point64, flags VertexFlags, prev *Vertex) *Vertex

type VertexFlags 

type VertexFlags uint8

type VertexPoolList 

type VertexPoolList []*Vertex

func (*VertexPoolList) Add 

func (vpl *VertexPoolList) Add(pt Point64, flags VertexFlags, prev *Vertex) *Vertex

func (*VertexPoolList) EnsureCapacity 

func (vpl *VertexPoolList) EnsureCapacity(nCap int)

Source Files

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