A very fast JavaScript library for clipping polylines and polygons by a bounding box.

• uses Cohen-Sutherland algorithm for line clipping
• uses Sutherland-Hodgman algorithm for polygon clipping

lineclip(
    [[-10, 10], [10, 10], [10, -10]], // line
    [0, 0, 20, 20]); // bbox
// returns [[[0, 10], [10, 10], [10, 0]]]

• points — an array of [x, y] points
• bbox — a bounding box as [xmin, ymin, xmax, ymax]
• result — an array to append the results to

Returns an array of clipped lines.

lineclip is an alias to lineclip.polyline.

Returns a clipped polygon.

Install with NPM:

npm install lineclip

To build a browser-compatible version, clone the repository locally, then run:

npm install -g browserify
browserify -s lineclip index.js > lineclip.js

• Fixed a bug where polygon clip broke on out-of-bbox polygons.

• Fixed a bug where last point was omitted if the last two points are in bbox.
• Fixed a bug where a line outside of bbox would produce [[]] instead of [].

• Fixed a polygon clipping race condition.

• Fixed a bug that completely broke the clipping on many cases. Sorry!

• Fixed a polyline clipping edge case.

• Added Sutherland-Hodgeman polygon clipping (lineclip.polygon).

• Minor code cleanup and optimizations.

• Initial release.