Kurbo is a Rust library for 2D vector geometry, primarily used in the Linebender ecosystem (e.g., the Vello rendering engine). It provides core geometric types such as BezPath, PathSeg, curves (cubic, quadratic, arc), affine transforms, and advanced algorithms for offset, stroke expansion, curve fitting, flattening, and polynomial root-finding. The architecture is a Cargo workspace with two crates: `kurbo` (main geometry library) and `polycool` (polynomial utilities). Key entry points include the `BezPath` builder, `ParamCurve` traits for generic curve operations, and high-level functions like `expand_path`, `stroke`, and `fit_to_bezpath`. External dependencies are optional (serde, euclid, mint, schemars) and the library supports no_std via the `libm` feature. Data flows involve constructing paths from elements, applying transformations, and then processing them for rendering or analysis. The codebase demonstrates strong numerical methods, trait-based abstractions, and careful handling of edge cases, making it a high-quality foundation for vector graphics applications.
BezierKit is a comprehensive Swift library for constructing, manipulating, and computing with Bézier curves and paths. It provides linear, quadratic, and cubic curve types, along with advanced operations including curve-curve intersection (via monotone subdivision with implicitization fallback), offsetting, boolean operations (union, subtract, intersect), bounding box computation, nearest-point projection, arc length via Legendre-Gauss quadrature, and self-intersection removal. The library is designed for cross-platform use (macOS, iOS, Linux, WebAssembly) and includes a macOS demo application for interactive testing. The codebase demonstrates strong software engineering practices: protocol-oriented design, extensive unit tests (including adversarial edge cases), performance optimizations (concrete type overloads, stack allocation, manual memory management in hot paths), and a clean separation of concerns. While pre-release (semver < 1.0) with some known numerical edge cases documented as expected failures, the library is production-ready for vector graphics, CAD, and computational geometry applications.