mirror of
https://github.com/lynchmarkHQ/lynchmark.com.git
synced 2026-10-08 21:35:23 +00:00
19 lines
611 B
JavaScript
19 lines
611 B
JavaScript
const findConvexHull = async (pts) => {
|
|
const { default: _ } = await import('https://esm.sh/lodash')
|
|
const u = _.uniqWith(pts, _.isEqual)
|
|
if (u.length < 3) return u
|
|
const s = _.sortBy(u, ['x', 'y'])
|
|
const cp = (a, b, c) => (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x)
|
|
const scan = (lst) => {
|
|
const h = []
|
|
lst.forEach(p => {
|
|
while (h.length >= 2 && cp(h[h.length - 2], h[h.length - 1], p) <= 0) h.pop()
|
|
h.push(p)
|
|
})
|
|
return h
|
|
}
|
|
const l = scan(s)
|
|
const uH = scan(s.reverse())
|
|
return _.concat(l.slice(0, -1), uH.slice(0, -1))
|
|
}
|
|
export default findConvexHull; |