Programmatically rotate shapes using coordinates

Question

If I have some shapes defined using arrays of coordinates e.g.

[[-30, -30], [-30, 30], [30, 30], [30, -30]]

and edges defined using:

Answer 1

You could use a formular for rotating the point around the origin.

function rotate(array, angle) {
    return array.map(function (p) {
        function r2d(a) { return a * Math.PI / 180; }
        return [
            Math.cos(r2d(angle)) * p[0] - Math.sin(r2d(angle)) * p[1],
            Math.sin(r2d(angle)) * p[0] - Math.cos(r2d(angle)) * p[1],
        ];
    });
}
console.log(rotate([[-30, -30], [-30, 30], [30, 30], [30, -30]], 45));
console.log(rotate([[-30, -30], [-30, 30], [30, 30], [30, -30]], 90));

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