captcha.min.js

function Captcha(params={}){let middleParams=Object.assign({lineWidth:0.5,lineNum:2,dotR:1,dotNum:15,preGroundColor:[10,80],backGroundColor:[150,250],fontSize:20,fontFamily:['Georgia','微软雅黑','Helvetica','Arial'],fontStyle:'fill',content:'acdefhijkmnpwxyABCDEFGHJKMNPQWXY12345789',length:4},params);Object.keys(middleParams).forEach(item=>{this[item]=middleParams[item]});this.canvas=null;this.paint=null};Captcha.prototype.getRandom=function(...arr){arr.sort((a,b)=>a-b);return Math.floor(Math.random()*(arr[1]-arr[0])+arr[0])};Captcha.prototype.getColor=function(arr){let colors=new Array(3).fill('');colors=colors.map(item=>this.getRandom(...arr));return colors};Captcha.prototype.getText=function(){let length=this.content.length;let str='';for(let i=0;i<this.length;i++){str+=this.content[this.getRandom(0,length)]}return str};Captcha.prototype.line=function(){for(let i=0;i<this.lineNum;i++){let x=this.getRandom(0,this.canvas.width);let y=this.getRandom(0,this.canvas.height);let endX=this.getRandom(0,this.canvas.width);let endY=this.getRandom(0,this.canvas.height);this.paint.beginPath();this.paint.lineWidth=this.lineWidth;let colors=this.getColor(this.preGroundColor);this.paint.strokeStyle='rgba('+colors[0]+','+colors[1]+','+colors[2]+','+'0.8)';this.paint.moveTo(x,y);this.paint.lineTo(endX,endY);this.paint.closePath();this.paint.stroke()}};Captcha.prototype.circle=function(){for(let i=0;i<this.dotNum;i++){let x=this.getRandom(0,this.canvas.width);let y=this.getRandom(0,this.canvas.height);this.paint.beginPath();this.paint.arc(x,y,this.dotR,0,Math.PI*2,false);this.paint.closePath();let colors=this.getColor(this.preGroundColor);this.paint.fillStyle='rgba('+colors[0]+','+colors[1]+','+colors[2]+','+'0.8)';this.paint.fill()}};Captcha.prototype.font=function(){let str=this.getText();this.callback(str);this.paint.font=this.fontSize+'px '+this.fontFamily[this.getRandom(0,this.fontFamily.length)];this.paint.textBaseline='middle';let fontStyle=this.fontStyle+'Text';let colorStyle=this.fontStyle+'Style';for(let i=0;i<this.length;i++){let fontWidth=this.paint.measureText(str[i]).width;let x=this.getRandom(this.canvas.width/this.length*i+0.2*fontWidth,(this.canvas.width/this.length)*i+0.5*fontWidth);let deg=this.getRandom(-6,6);let colors=this.getColor(this.preGroundColor);this.paint[colorStyle]='rgba('+colors[0]+','+colors[1]+','+colors[2]+','+'0.8)';this.paint.save();this.paint.rotate(deg*Math.PI/180);this.paint[fontStyle](str[i],x,this.canvas.height/2);this.paint.restore()}};Captcha.prototype.draw=function(dom,callback=function(){}){if(!this.paint){this.canvas=dom;if(!this.canvas)return;else this.paint=this.canvas.getContext('2d');this.callback=callback;this.canvas.onclick=()=>{this.drawAgain()}}let colors=this.getColor(this.backGroundColor);this.paint.fillStyle='rgba('+colors[0]+','+colors[1]+','+colors[2]+','+'0.8)';this.paint.fillRect(0,0,this.canvas.width,this.canvas.height);this.circle();this.line();this.font()};Captcha.prototype.clear=function(){this.paint.clearRect(0,0,this.canvas.width,this.canvas.height)};Captcha.prototype.drawAgain=function(){this.clear();this.draw(this.callbak)};if(typeof module!=='undefined'&&!module.nodeType&&module.exports){module.exports=Captcha}