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freesewing/lib/point.ts
2018-07-12 07:37:52 +00:00

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TypeScript

const PRECISION = 2;
const RAD = 57.29577951308232;
export default class Point {
x: number;
y: number;
constructor(x: number, y: number) {
this.x = +x.toFixed(PRECISION);
this.y = +y.toFixed(PRECISION);
return this;
}
/** Returns the distance between this point and that point */
distance(that: Point): number {
let dx = this.x - that.x;
let dy = this.y - that.y;
return Math.sqrt(Math.pow(dx, 2) + Math.pow(dy,2));
}
/** Returns slope of a line made by this point and that point */
slope(that: Point): number {
return (that.y - this.y) / (that.x - this.x);
}
/** Returns the angle between this point and that point */
angle(that: Point): number {
let dx = this.x - that.x;
let dy = this.y - that.y;
let rad = Math.atan2(-1 * dy, dy);
while (rad < 0) rad += 2 * Math.PI;
// A poor man's rad2deg()
return rad * RAD;
}
/** Rotate this point degrees around that point */
rotate(degrees: number, that: Point) {
let radius = this.distance(that);
let angle = this.angle(that);
let x = that.x + radius * Math.cos((angle + degrees) / RAD) * -1;
let y = that.y + radius * Math.sin((angle + degrees) / RAD);
return new Point(x, y);
}
/** Shifts this point distance in the degrees direction */
shift(degrees: number, distance: number): Point {
let p = this.copy();
p.x += distance;
return p.rotate(degrees, this);
}
/** returns an identical copy of this point */
copy(): Point {
return new Point(this.x, this.y);
}
}