qtsd-fork/example/node_modules/react-dnd-html5-backend/lib/MonotonicInterpolant.js

Do not use this please

"use strict";

Object.defineProperty(exports, "__esModule", {
	value: true
});

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

/* eslint
   no-plusplus: off,
   no-mixed-operators: off
*/
var MonotonicInterpolant = function () {
	function MonotonicInterpolant(xs, ys) {
		_classCallCheck(this, MonotonicInterpolant);

		var length = xs.length;

		// Rearrange xs and ys so that xs is sorted
		var indexes = [];
		for (var i = 0; i < length; i++) {
			indexes.push(i);
		}
		indexes.sort(function (a, b) {
			return xs[a] < xs[b] ? -1 : 1;
		});

		// Get consecutive differences and slopes
		var dys = [];
		var dxs = [];
		var ms = [];
		var dx = void 0;
		var dy = void 0;
		for (var _i = 0; _i < length - 1; _i++) {
			dx = xs[_i + 1] - xs[_i];
			dy = ys[_i + 1] - ys[_i];
			dxs.push(dx);
			dys.push(dy);
			ms.push(dy / dx);
		}

		// Get degree-1 coefficients
		var c1s = [ms[0]];
		for (var _i2 = 0; _i2 < dxs.length - 1; _i2++) {
			var _m = ms[_i2];
			var mNext = ms[_i2 + 1];
			if (_m * mNext <= 0) {
				c1s.push(0);
			} else {
				dx = dxs[_i2];
				var dxNext = dxs[_i2 + 1];
				var common = dx + dxNext;
				c1s.push(3 * common / ((common + dxNext) / _m + (common + dx) / mNext));
			}
		}
		c1s.push(ms[ms.length - 1]);

		// Get degree-2 and degree-3 coefficients
		var c2s = [];
		var c3s = [];
		var m = void 0;
		for (var _i3 = 0; _i3 < c1s.length - 1; _i3++) {
			m = ms[_i3];
			var c1 = c1s[_i3];
			var invDx = 1 / dxs[_i3];
			var _common = c1 + c1s[_i3 + 1] - m - m;
			c2s.push((m - c1 - _common) * invDx);
			c3s.push(_common * invDx * invDx);
		}

		this.xs = xs;
		this.ys = ys;
		this.c1s = c1s;
		this.c2s = c2s;
		this.c3s = c3s;
	}

	_createClass(MonotonicInterpolant, [{
		key: "interpolate",
		value: function interpolate(x) {
			var xs = this.xs,
			    ys = this.ys,
			    c1s = this.c1s,
			    c2s = this.c2s,
			    c3s = this.c3s;

			// The rightmost point in the dataset should give an exact result

			var i = xs.length - 1;
			if (x === xs[i]) {
				return ys[i];
			}

			// Search for the interval x is in, returning the corresponding y if x is one of the original xs
			var low = 0;
			var high = c3s.length - 1;
			var mid = void 0;
			while (low <= high) {
				mid = Math.floor(0.5 * (low + high));
				var xHere = xs[mid];
				if (xHere < x) {
					low = mid + 1;
				} else if (xHere > x) {
					high = mid - 1;
				} else {
					return ys[mid];
				}
			}
			i = Math.max(0, high);

			// Interpolate
			var diff = x - xs[i];
			var diffSq = diff * diff;
			return ys[i] + c1s[i] * diff + c2s[i] * diffSq + c3s[i] * diff * diffSq;
		}
	}]);

	return MonotonicInterpolant;
}();

exports.default = MonotonicInterpolant;