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• About
• Status
• Related packages
• Installation
• Dependencies
• API
• Authors
• License

About

2D line clipping (Liang-Barsky). This is a support package for @thi.ng/geom.

Current implementation is partially based on toxiclibs (Java) and Clojure version thi.ng/geom-clj. Also see @thi.ng/geom-clip-poly sister package.

The following main functions are provided:

• clipLinePoly()
• clipLineSegmentPoly()
• clipPolylinePoly()
• liangBarsky2()

Status

STABLE - used in production

Search or submit any issues for this package

Related packages

• @thi.ng/geom-clip-poly - 2D polygon clipping / offsetting (Sutherland-Hodgeman, Grainer-Hormann)

Installation

yarn add @thi.ng/geom-clip-line

ESM import:

import * as gcl from "@thi.ng/geom-clip-line";

Browser ESM import:

<script type="module" src="https://esm.run/@thi.ng/geom-clip-line"></script>

JSDelivr documentation

For Node.js REPL:

const gcl = await import("@thi.ng/geom-clip-line");

Package sizes (brotli'd, pre-treeshake): ESM: 762 bytes

Dependencies

• @thi.ng/api
• @thi.ng/geom-isec
• @thi.ng/vectors

Note: @thi.ng/api is in most cases a type-only import (not used at runtime)

API

Generated API docs

import { clipPolylinePoly, liangBarsky2 } from "@thi.ng/geom-clip-line";

clipPolylinePoly(
    // polyline vertices
    [[10, -50], [30, 30], [-50, 50], [150, 50], [70, 70], [90, 150]],
    // boundary polygon vertices
    [[0, 0], [100, 0], [100, 100], [0, 100]]
);
// result is 3 polylines:
// (since the original is temporarily leaving the poly)
// [
//   [ [ 22.5, 0 ], [ 30, 30 ], [ 0, 37.5 ] ],
//   [ [ 0, 50 ], [ 100, 50 ] ],
//   [ [ 100, 62.5 ], [ 70, 70 ], [ 77.5, 100 ] ]
// ]

// Liang-Barsky is optimized for rectangular clipping regions
liangBarsky2(
    // line end points
    [-10, -20], [30, 400],
    // min/max clip rect
    [0, 0], [100, 200]
)
// [ [ 0, 85 ], [ 10.952380952380953, 200 ], 0.25, 0.5238095238095238 ]

// returns undefined if line is completely outside the clip rect
liangBarsky2(
    // line end points
    [-10, -20], [-30, 400],
    // min/max bbox
    [0, 0], [100, 200]
)
// undefined

Authors

• Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

@misc{thing-geom-clip-line,
  title = "@thi.ng/geom-clip-line",
  author = "Karsten Schmidt",
  note = "https://thi.ng/geom-clip-line",
  year = 2013
}

License

© 2013 - 2025 Karsten Schmidt // Apache License 2.0