@visx/vendor/vendor-cjs/d3-geo/src/interpolate.js

vendored packages for visx

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = _default;
var _math = require("./math.js");
function _default(a, b) {
  var x0 = a[0] * _math.radians,
    y0 = a[1] * _math.radians,
    x1 = b[0] * _math.radians,
    y1 = b[1] * _math.radians,
    cy0 = (0, _math.cos)(y0),
    sy0 = (0, _math.sin)(y0),
    cy1 = (0, _math.cos)(y1),
    sy1 = (0, _math.sin)(y1),
    kx0 = cy0 * (0, _math.cos)(x0),
    ky0 = cy0 * (0, _math.sin)(x0),
    kx1 = cy1 * (0, _math.cos)(x1),
    ky1 = cy1 * (0, _math.sin)(x1),
    d = 2 * (0, _math.asin)((0, _math.sqrt)((0, _math.haversin)(y1 - y0) + cy0 * cy1 * (0, _math.haversin)(x1 - x0))),
    k = (0, _math.sin)(d);
  var interpolate = d ? function (t) {
    var B = (0, _math.sin)(t *= d) / k,
      A = (0, _math.sin)(d - t) / k,
      x = A * kx0 + B * kx1,
      y = A * ky0 + B * ky1,
      z = A * sy0 + B * sy1;
    return [(0, _math.atan2)(y, x) * _math.degrees, (0, _math.atan2)(z, (0, _math.sqrt)(x * x + y * y)) * _math.degrees];
  } : function () {
    return [x0 * _math.degrees, y0 * _math.degrees];
  };
  interpolate.distance = d;
  return interpolate;
}