linkcad.libgraph

High-performance boolean geometry engine for polygon operations. Wraps the native libgraph library.

from linkcad.libgraph import (
    ShapeProcessor, ShapeGroup, Operation, FillRule, HolesMode, Result,
    boolean_and, boolean_or, boolean_xor, boolean_difference,
)

Convenience Functions

For simple two-polygon operations, use these functions directly. Each function accepts vertex lists as sequences of (x, y) tuples and returns a list of result polygons (each a list of (x, y) tuples).

from linkcad.libgraph import boolean_and, boolean_or, boolean_xor, boolean_difference

square   = [(0, 0), (10, 0), (10, 10), (0, 10)]
triangle = [(5, 5), (15, 5), (10, 15)]

# Intersection
result = boolean_and(square, triangle)

# Union
result = boolean_or(square, triangle)

# Exclusive OR
result = boolean_xor(square, triangle)

# Difference (square minus triangle)
result = boolean_difference(square, triangle)

Function	Description
`boolean_and(vtx1, vtx2, fill_rule=FillRule.NonZero)`	Intersection of two polygons
`boolean_or(vtx1, vtx2, fill_rule=FillRule.NonZero)`	Union of two polygons
`boolean_xor(vtx1, vtx2, fill_rule=FillRule.NonZero)`	Symmetric difference of two polygons
`boolean_difference(vtx1, vtx2, fill_rule=FillRule.NonZero)`	Difference — regions in `vtx1` but not `vtx2`

ShapeProcessor

For multi-polygon operations or full control over the operation, use ShapeProcessor:

from linkcad.libgraph import ShapeProcessor, ShapeGroup, Operation

sp = ShapeProcessor()

sp.add_polygon(ShapeGroup.A, [(0, 0), (10, 0), (10, 10), (0, 10)])
sp.add_polygon(ShapeGroup.B, [(5, 5), (15, 5), (10, 15)])

sp.execute(Operation.And)

results = []
while True:
    poly = sp.get_next_polygon()
    if poly is None:
        break
    results.append(poly)

Method	Description
`ShapeProcessor()`	Create a new processor instance
`sp.add_polygon(group, vertices)`	Add a polygon to group A, B, or AB
`sp.execute(operation)`	Run the specified boolean operation
`sp.get_next_polygon()`	Retrieve the next result polygon; returns `None` when exhausted
`sp.result`	`Result` status of the last `execute()` call

Enums

ShapeGroup

Determines which operand a polygon belongs to.

Value	Description
`ShapeGroup.A`	First operand
`ShapeGroup.B`	Second operand
`ShapeGroup.AB`	Belongs to both operands simultaneously

Operation

The boolean operation to perform.

Value	Description
`Operation.Or`	Union (A ∪ B)
`Operation.And`	Intersection (A ∩ B)
`Operation.Xor`	Symmetric difference (A △ B)
`Operation.AMinusB`	Difference (A − B)
`Operation.BMinusA`	Difference (B − A)

FillRule

Controls how overlapping polygon edges determine “inside” vs “outside”.

Value	Description
`FillRule.NonZero`	Non-zero winding rule (standard EDA convention)
`FillRule.EvenOdd`	Even-odd rule

HolesMode

Controls how holes in output polygons are represented.

Value	Description
`HolesMode.Extract`	Return holes as separate reversed polygons
`HolesMode.Link`	Connect holes to the outer boundary with zero-width bridges
`HolesMode.Split`	Split result into simple polygons with no holes

Result

Status of the last ShapeProcessor.execute() call.

Value	Description
`Result.Ok`	Operation succeeded
`Result.Error`	Operation failed