Liang-Barsky line-clipping algorithm 
Fast, destructive implemetation of Liang-Barsky line clipping algorithm. It clips a 2D segment by a rectangle.
This is an adaptation of the C++ code that impressed me by its simplicity.
API
Destructive
var a = [-10, -10], b = [10, 10];
clip(a, b, [-5, -5, 5, 5]); // returns 1 - "clipped"
console.log(a); // [-5, -5]
console.log(b); // [5, 5]Non-destructive
var a = [-10, -10], b = [10, 10];
var an = a.slice(), bn = b.slice();
clip(a, b, [-5, -5, 5, 5], an, bn); // returns 1 - "clipped"
console.log(an); // [-5, -5]
console.log(bn); // [5, 5]
console.log(a); // [-10, -10]
console.log(b); // [10, 10]Return value is 1 if the line was clipped, and 0 if it lies completely
outside of the provided bounding box.
Install
npm install -S liang-barsky
import clip from 'liang-barsky';
// or
var clip = require('liang-barsky');Or just drop-in the file
<script src="path/to/liang-barsky.umd.js"></script>
<script>
liangBarsky([0, 0], [10, 10], [0, 0, 5, 5]);
</script>Performance
I ran a check against the Cohen-Sutherland algorithm implemented by @mourner for clipping just one segment. Though test include memory allocation, they are fair for the task at hand, since you can use the results in an equal manner after the invocation of the clipper.
npm run benchmark
liang-barsky x 136,671,492 ops/sec ±0.36% (90 runs sampled)
mapbox/lineclip x 9,030,039 ops/sec ±0.84% (86 runs sampled)
- Fastest is liang-barsky
Future plan
Implement a sub-routine for polylines. Loop through pairs, tracking in-out transitions.
License
MIT