js判断向量交点 并求出交点坐标
<!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>画椭圆</title> <style> .title{text-align:center;} .wrapper{width: 500px;height: 500px;margin: 0 auto;border: 1px solid #000000;} .content{position: relative;height: 500px;} .dot{position: absolute;width:1px;height: 1px;overflow: hidden;font-size:0;line-height: 0; background: #333;} </style> </head> <body> <h1 class="title">判断相交并求交点</h1> <div class="wrapper"> <div class="content" id="content"></div> </div> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script> <script> //*********定义加载模块方法 start **************// (function (window, undefined) { if (window.define) { return } function isFunction(obj) { return Object.prototype.toString.call(obj) === "[object Function]" } var MM = {}; var initModuleName = "initRun"; function require(name) { if (!MM[name]) { throw new Error("Module " + name + " is not defined.") } var module = MM[name]; if (module.inited === false) { runModule(name) } return module.ret } function runModule(name) { var exports = {}; var module = MM[name]; if (isFunction(MM[name].factory)) { var ret = MM[name].factory.apply(undefined, [require, exports, undefined]); module.ret = ret === undefined ? exports : ret } else { module.ret = MM[name].factory } module.inited = true } function define(name, deps, factory) { if (MM[name]) { throw new Error("Module " + name + " has been defined already.") } if (isFunction(deps)) { factory = deps } MM[name] = {factory:factory, inited:false}; if (name === initModuleName) { runModule(name) } } window.define = define })(window); //*********定义加载模块方法 end **************// (function(){ /** * 可以缓存的操作节点 */ var $dom = { content : $(‘#content‘) } define(‘Mode/drawLine‘,function(require){ var drawLine = function(){}; drawLine.prototype = { /** * @根据两坐标画线段 * @param vector1 * @param vector2 */ draw : function(vector1 ,vector2){ var k = (vector2.y - vector1.y)/((vector2.x - vector1.x));//求斜率k var y,x ;_lineHtml = [];//用来保存xy变量坐标 var max = Math.max(vector2.x,vector1.x), min = Math.min(vector2.x,vector1.x); if(max != min){ for(var i = min;i<max;i++){ y = k * (i - vector1.x) + vector1.y; _lineHtml.push(‘<div class="dot" style="left:‘+ i +‘px;top:‘+ y +‘px"></div>‘); } }else{ max = Math.max(vector2.y,vector1.y), min = Math.min(vector2.y,vector1.y); for(var i = min;i<max;i++){ x = (i - vector1.y)/k + vector1.y; _lineHtml.push(‘<div class="dot" style="left:‘+ x +‘px;top:‘+ i +‘px"></div>‘); } } $dom.content.append(_lineHtml.join(‘‘)) ; } , /** * @desc求交点坐标具体算法见http://www.cnblogs.com/rubyxie/articles/3548450.html * @param vector1 * @param vector2 * @param vector3 * @param vector4 * @return {Object}交点坐标 */ computeCrossVector : function (vector1 ,vector2,vector3 ,vector4){ var crossVector = {}, v1 = {"x" : vector2.x - vector1.x , "y" : vector2.y - vector1.y}, v2 = {"x" : vector4.x - vector3.x , "y" : vector4.y - vector3.y}; var product = v1.x * v2.y - v1.y * v2.x; //两向量的乘积 //计算二阶行列式的两个常数项 var const1 = vector1.x * v1.y - vector1.y * v1.x ; const2 = vector3.x * v2.y - vector3.y * v2.x ; crossVector.x = (const2 * v1.x - const1 * v2.x)/product; crossVector.y = (const2 * v1.y - const1 * v2.y)/product; return crossVector; } , //向量叉乘 crossMul: function (v1, v2) { return v1.x * v2.y - v1.y * v2.x; } , checkLineCross : function(vector1 ,vector2,vector3 ,vector4){ var v1 = {x: vector1.x - vector3.x, y: vector1.y - vector3.y}, v2 = {x: vector2.x - vector3.x, y: vector2.y - vector3.y}, v3 = {x: vector4.x - vector3.x, y: vector4.y - vector3.y}, v = this.crossMul(v1, v3) * this.crossMul(v2, v3), v1 = {x: vector3.x - vector1.x, y: vector3.y - vector1.y}, v2 = {x: vector4.x - vector1.x, y: vector4.y - vector1.y}, v3 = {x: vector2.x - vector1.x, y: vector2.y - vector1.y}; return (v <= 0 && this.crossMul(v1, v3) * this.crossMul(v2, v3) <= 0) ? true : false; } }; return drawLine; }); /** * @desc 模块启动函数 */ define(‘initRun‘,function(require){ var vector1 = {"x" :20 ,"y":20 }, //定义四个向量坐标 vector2 = {"x" :400 ,"y":400 }, vector3 = {"x" :10 ,"y":104 }, vector4 = {"x" :200 ,"y":104 }; var drawMode = require("Mode/drawLine"); var line = new drawMode; line.draw(vector1,vector2); line.draw(vector3,vector4); if(line.checkLineCross(vector1,vector2,vector3,vector4)){ var cross = line.computeCrossVector(vector1,vector2,vector3,vector4); $dom.content.append(‘<div>交点坐标为:x坐标为 ‘+ cross.x + ‘ y坐标 :‘+cross.y+‘</div>‘); }else{ alert("这两向量线段未相交"); } }) })(); </script> </body> </html>
代码如上可以直接运行,判断向量相交并求出交点坐标
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