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@black-black-cat

black-black-cat/index.html

Last active November 11, 2019 09:22
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get rotated corners
Raw
index.html
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>GistRun</title>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<h1>Hello world!</h1>
<script src="script.js"></script>
</body>
</html>
Raw
script.js
function getRotatedCorners (corners, angle = 0) {
return corners.map(v => {
return vRotate(v, angle)
})
}
let {
PI,
cos,
sin,
min,
max
} = Math
function vRotate (v, angle, deg = true) {
if (deg) {
angle = angle * PI / 180
}
let x = v[0]
let y = v[1]
let ret = [
approxFix( x * cos(angle) - y * sin(angle) ),
approxFix( x * sin(angle) + y * cos(angle) )
]
return ret
}
let innerCorners = getRotatedCorners([[2, 1], [-2, 1], [-2, -1], [2, -1]], 15)
console.log(innerCorners)
function approxFix (num, pow = 3) {
let factor = Math.pow(10, pow)
let fixed = Math.round(num * factor) / factor
let shouldFix = Math.abs(fixed - num) < 10e-8
return shouldFix ? fixed : num
}
function getOuterRect (innerCorners) {
let xCoords = []
let yCoords = []
innerCorners.forEach(v => {
xCoords.push(v[0])
yCoords.push(v[1])
})
let tl = [min.apply(null, xCoords), min.apply(null, yCoords)]
let br = [max.apply(null, xCoords), max.apply(null, yCoords)]
let tr = [br[0], tl[1]]
let bl = [tl[0], br[1]]
return {
corners: [br, bl, tl, tr],
width: br[0] - tl[0],
height: br[1] - tl[1]
}
}
console.log(getOuterRect(innerCorners))
Raw
styles.css
/* todo: add styles */
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