106 lines
2.4 KiB
JavaScript
106 lines
2.4 KiB
JavaScript
/**
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* 根据弧线的坐标节点数组
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*/
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function getCurvePoints(points, options) {
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options = options || {};
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var curvePoints = [];
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for (var i = 0; i < points.length - 1; i++) {
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var p = getCurveByTwoPoints(points[i], points[i + 1], options.count);
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if (p && p.length > 0) {
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curvePoints = curvePoints.concat(p);
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}
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}
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return curvePoints;
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}
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/**
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* 根据两点获取曲线坐标点数组
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* @param Point 起点
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* @param Point 终点
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*/
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function getCurveByTwoPoints(obj1, obj2, count) {
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if (!obj1 || !obj2) {
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return null;
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}
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var B1 = function(x) {
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return 1 - 2 * x + x * x;
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};
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var B2 = function(x) {
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return 2 * x - 2 * x * x;
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};
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var B3 = function(x) {
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return x * x;
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};
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var curveCoordinates = [];
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var count = count || 40; // 曲线是由一些小的线段组成的，这个表示这个曲线所有到的折线的个数
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var isFuture = false;
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var t, h, h2, lat3, lng3, j, t2;
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var LnArray = [];
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var i = 0;
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var inc = 0;
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if (typeof(obj2) == "undefined") {
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if (typeof(curveCoordinates) != "undefined") {
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curveCoordinates = [];
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}
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return;
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}
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var lat1 = parseFloat(obj1.lat);
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var lat2 = parseFloat(obj2.lat);
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var lng1 = parseFloat(obj1.lng);
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var lng2 = parseFloat(obj2.lng);
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// 计算曲线角度的方法
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if (lng2 > lng1) {
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if (parseFloat(lng2-lng1) > 180) {
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if (lng1 < 0) {
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lng1 = parseFloat(180 + 180 + lng1);
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}
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}
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}
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if (lng1 > lng2) {
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if (parseFloat(lng1-lng2) > 180) {
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if (lng2 < 0) {
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lng2 = parseFloat(180 + 180 + lng2);
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}
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}
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}
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j = 0;
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t2 = 0;
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if (lat2 == lat1) {
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t = 0;
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h = lng1 - lng2;
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} else if (lng2 == lng1) {
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t = Math.PI / 2;
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h = lat1 - lat2;
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} else {
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t = Math.atan((lat2 - lat1) / (lng2 - lng1));
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h = (lat2 - lat1) / Math.sin(t);
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}
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if (t2 == 0) {
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t2 = (t + (Math.PI / 5));
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}
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h2 = h / 2;
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lng3 = h2 * Math.cos(t2) + lng1;
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lat3 = h2 * Math.sin(t2) + lat1;
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for (i = 0; i < count + 1; i++) {
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curveCoordinates.push([
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(lng1 * B1(inc) + lng3 * B2(inc)) + lng2 * B3(inc),
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(lat1 * B1(inc) + lat3 * B2(inc) + lat2 * B3(inc))
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]);
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inc = inc + (1 / count);
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}
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return curveCoordinates;
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}
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function Point (lng, lat) {
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this.lng = lng;
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this.lat = lat;
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}
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