vis-utils/lib/rotate.js

Utility functions for data visualization

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = rotate;
var X = 0;
var Y = 1;

/**
 * Rotate a point ([x, y]) around an origin ([x, y]) by theta radians
 *
 * @param {Number[]} point [x, y]
 * @param {Number} thetaRadians How many radians to rotate the point around origin
 * @param {Number[]} [origin] [x, y] (defaults to [0, 0])
 *
 * @return {Number[]} The rotated point [x, y]
 */
function rotate(point, thetaRadians) {
  var origin = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : [0, 0];

  var rotatedEndX = origin[X] + (point[X] - origin[X]) * Math.cos(thetaRadians) - (point[Y] - origin[Y]) * Math.sin(thetaRadians);
  var rotatedEndY = origin[Y] + (point[X] - origin[X]) * Math.sin(thetaRadians) + (point[Y] - origin[Y]) * Math.cos(thetaRadians);

  return [rotatedEndX, rotatedEndY];
}