https://github.com/rowanwins/kwc-lineclip

Line clipping based on the algorithm by Kodituwakka, Wijeweera & Chamikara
https://github.com/rowanwins/kwc-lineclip

algorithm clipping geometry

Last synced: 11 days ago
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Line clipping based on the algorithm by Kodituwakka, Wijeweera & Chamikara

• Host: GitHub
• URL: https://github.com/rowanwins/kwc-lineclip
• Owner: rowanwins
• License: mit
• Created: 2018-01-22T23:09:51.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2018-03-12T21:52:35.000Z (over 6 years ago)
• Last Synced: 2024-10-22T22:32:17.195Z (16 days ago)
• Topics: algorithm, clipping, geometry
• Language: JavaScript
• Size: 218 KB
• Stars: 11
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
## kwc-lineclip

A small javascript lib for clipping polylines by a bounding box.

### Install

````

npm install kwc-lineclip

````

### API

```js

lineclip(

    [[-10, 10], [10, 10], [10, -10]], // polyline

    [0, 0, 20, 20]); // bbox

// returns [[[0, 10], [10, 10], [10, 0]]]

```

### Algorithm

This library is an implementation of the approach described in ['An Efficient Algorithm for Line Clipping in Computer Graphics Programming'](http://www.academia.edu/2491960/An_Efficient_Algorithm_for_Line_Clipping_in_Computer_Graphics_Programming) by Kodituwakka, Wijeweera & Chamikara. Some adjustments have been made to the algorithm in the paper to cater for lines with multiple segments.

### Performance

I've checked the performance of this algorithm against implementations of the [Cohen-Sutherland](https://github.com/mapbox/lineclip) and a [Liang-barsky](https://github.com/w8r/liang-barsky) algorithms for clipping just one segment. Liang-barsky currently only supports a single segment clip.

````

SINGLE SEGMENT TEST

kwc x 9,542,273 ops/sec ±1.78% (100 runs sampled)

liang-barsky (non-destructive) x 17,583,416 ops/sec ±2.89% (99 runs sampled)

mapbox/lineclip x 7,022,569 ops/sec ±8.14% (95 runs sampled)

- Fastest is liang-barsky (non-destructive)

MULTIPLE SEGMENT MULTIPLE OUTPUT TEST

kwc x 4,974,886 ops/sec ±6.84% (82 runs sampled)

mapbox/lineclip x 3,788,980 ops/sec ±0.70% (88 runs sampled)

- Fastest is kwc

LONGER LINE

kwc x 800,189 ops/sec ±0.79% (93 runs sampled)

mapbox/lineclip x 704,052 ops/sec ±2.53% (88 runs sampled)

- Fastest is kwc

````

kwc-lineclip was initially faster than liang-barsky until I amended the algorithm to support multiple segments.

Memory usage is also slightly less in with this module compared with `lineclip`.