https://github.com/stuartpb/chachacat

Chained Hulling Algorithm for Convex Hull Area of Canvas Alpha Threshold
https://github.com/stuartpb/chachacat

Last synced: 7 days ago
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Chained Hulling Algorithm for Convex Hull Area of Canvas Alpha Threshold

• Host: GitHub
• URL: https://github.com/stuartpb/chachacat
• Owner: stuartpb
• License: mit
• Created: 2015-07-24T07:45:28.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2024-07-08T22:27:23.000Z (6 months ago)
• Last Synced: 2024-07-09T03:21:40.508Z (6 months ago)
• Language: JavaScript
• Homepage: https://stuartpb.github.io/chachacat/demo.html
• Size: 205 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# chachacat

Chained Hulling Algorithm for Convex Hull Area of Canvas Alpha Threshold

![Convex hull demo](https://cloud.githubusercontent.com/assets/572196/8876272/812cac00-31d3-11e5-900f-8322b41f294e.png)

This function calculates the [convex hull][] of pixels in a given image's alpha

channel (above a certain threshold - 64 by default) and returns the area of

that hull.

[convex hull]: https://en.wikipedia.org/wiki/Convex_hull

This yields a decent approximation of the image content's area, in terms of

space occupied by the image. This can then be used for, say, normalizing the

size of icons on a menu, rather than [trusting developers to figure out][1],

which, in practice, doesn't really work.

[1]: https://developer.chrome.com/docs/webstore/images#icon-size