pathtrim v1.0.1

Path trim

This is a simple library that takes a list of paths and a list of polygons, and does a boolean subtraction. It returns either the parts of the paths which lie outside the polygonal area, or the parts of the paths which lie inside it.

Right now due to a bug (laziness) in pslg-to-paths the paths themselves get chopped up. Sorry about this.

API

const pathtrim = require('pathtrim')

const pathResult = pathtrim(<paths list>, <polygon list>, isIntersect)

• Paths list is specified as a list of paths, and each path is a list of connected points. Eg: [[[-100, 100], [100, -100]]]
• Polygon list is a list of polygons. Each polygon is a list of points that make up the polygon.
• isIntersect if true, keep the intersection of the polygon and lines. If false, discard the intersection and keep everything else
• Result is a list of paths

Example

const pathtrim = require('pathtrim')

const paths = pathtrim([
  [[-100, -100], [100, 100]]
], [
  [[-2, 1], [2, 1], [2, -1], [-2,-1]]  // Rectangle around origin
], true)

// Paths contains [[[-1, -1], [1, 1]]]

TODO:

• Improve pslg-to-paths so it doesn't mince up the paths into chum
• Do basic occlusion culling on paths and polys for performance

License

ISC