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/** * Copyright (c) 2017 ~ present NAVER Corp. * billboard.js project is licensed under the MIT license * @ignore */import {getRange, isEmpty, isFunction, isString, parseDate} from "../../module/util";
/** * Check if point is in region * @param {object} point Point * @param {Array} region Region * @returns {boolean} * @private */function pointInRegion(point, region): boolean { // thanks to: http://bl.ocks.org/bycoffe/5575904	// ray-casting algorithm based on	// http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html	const x = point.x;	const y = point.value;	let inside = false;
	for (let i = 0, j = region.length - 1; i < region.length; j = i++) {		const xi = region[i].x;		const yi = region[i].y;
		const xj = region[j].x;		const yj = region[j].y;
		const intersect = ((yi > y) !== (yj > y)) && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
		if (intersect) {			inside = !inside;		}	}
	return inside;}
/** * Compare epochs * @param {object} a Target * @param {object} b Source * @returns {number} * @private */function compareEpochs(a, b): number {	if (a.epochs < b.epochs) {		return -1;	}
	if (a.epochs > b.epochs) {		return 1;	}
	return 0;}
/** * Get region area * @param {Array} points Points * @returns {number} * @private */function getRegionArea(points): number { // thanks to: https://stackoverflow.com/questions/16282330/find-centerpoint-of-polygon-in-javascript	let area = 0;	let point1;	let point2;
	for (let i = 0, l = points.length, j = l - 1; i < l; j = i, i++) {		point1 = points[i];		point2 = points[j];		area += point1.x * point2.y;		area -= point1.y * point2.x;	}
	area /= 2;
	return area;}
/** * Get centroid * @param {Array} points Points * @returns {object} * @private */function getCentroid(points) {	const area = getRegionArea(points);
	let x = 0;	let y = 0;	let f;
	for (let i = 0, l = points.length, j = l - 1; i < l; j = i, i++) {		const point1 = points[i];		const point2 = points[j];
		f = point1.x * point2.y - point2.x * point1.y;		x += (point1.x + point2.x) * f;		y += (point1.y + point2.y) * f;	}
	f = area * 6;
	return {		x: x / f,		y: y / f	};}
export {	compareEpochs,	getCentroid,	getRange,	getRegionArea,	isEmpty,	isFunction,	isString,	parseDate,	pointInRegion};