利用canvas绘制带干扰线的验证码

<!DOCTYPE html>

<head>

<title>Document</title>

</head>

<body>

</body>

(function(window, document) {

function GVerify(options) { //创建一个图形验证码对象，接收options对象为参数

this.options = { //默认options参数值

id: "", //容器Id

canvasId: "verifyCanvas", //canvas的ID

width: "100", //默认canvas宽度

height: "30", //默认canvas高度

type: "blend", //图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母

code: ""

}

if (Object.prototype.toString.call(options) == "[object Object]") { //判断传入参数类型

for (var i in options) { //根据传入的参数，修改默认参数值

this.options[i] = options[i];

}

} else {

this.options.id = options;

}

this.options.numArr = "0,1,2,3,4,5,6,7,8,9".split(",");

this.options.letterArr = getAllLetter();

this._init();

this.refresh();

}

GVerify.prototype = {

/**版本号**/

version: '1.0.0',

/**初始化方法**/

_init: function() {

var con = document.getElementById(this.options.id);

var canvas = document.createElement("canvas");

this.options.width = con.offsetWidth > 0 ? con.offsetWidth : "100";

this.options.height = con.offsetHeight > 0 ? con.offsetHeight : "30";

canvas.id = this.options.canvasId;

canvas.width = this.options.width;

canvas.height = this.options.height;

canvas.style.cursor = "pointer";

canvas.innerHTML = "您的浏览器版本不支持canvas";

con.appendChild(canvas);

var parent = this;

canvas.onclick = function() {

parent.refresh();

}

/**生成验证码**/

refresh: function() {

this.options.code = "";

var canvas = document.getElementById(this.options.canvasId);

if (canvas.getContext) {

var ctx = canvas.getContext('2d');

} else {

return;

}

ctx.textBaseline = "middle";

ctx.fillStyle = randomColor(180, 240);

ctx.fillRect(0, 0, this.options.width, this.options.height);

if (this.options.type == "blend") { //判断验证码类型

var txtArr = this.options.numArr.concat(this.options.letterArr);

} else if (this.options.type == "number") {

var txtArr = this.options.numArr;

} else {

var txtArr = this.options.letterArr;

}

for (var i = 1; i <= 4; i++) {

var txt = txtArr[randomNum(0, txtArr.length)];

this.options.code += txt;

ctx.font = randomNum(this.options.height / 2, this.options.height) + 'px SimHei'; //随机生成字体大小

ctx.fillStyle = randomColor(50, 160); //随机生成字体颜色

ctx.shadowOffsetX = randomNum(-3, 3);

ctx.shadowOffsetY = randomNum(-3, 3);

ctx.shadowBlur = randomNum(-3, 3);

ctx.shadowColor = "rgba(0, 0, 0, 0.3)";

var x = this.options.width / 5 * i;

var y = this.options.height / 2;

var deg = randomNum(-30, 30);

/**设置旋转角度和坐标原点**/

ctx.translate(x, y);

ctx.rotate(deg * Math.PI / 180);

ctx.fillText(txt, 0, 0);

/**恢复旋转角度和坐标原点**/

ctx.rotate(-deg * Math.PI / 180);

ctx.translate(-x, -y);

}

/**绘制干扰线**/

for (var i = 0; i < 4; i++) {

ctx.strokeStyle = randomColor(40, 180);

ctx.beginPath();

ctx.moveTo(randomNum(0, this.options.width), randomNum(0, this.options.height));

ctx.lineTo(randomNum(0, this.options.width), randomNum(0, this.options.height));

ctx.stroke();

}

/**绘制干扰点**/

for (var i = 0; i < this.options.width / 4; i++) {

ctx.fillStyle = randomColor(0, 255);

ctx.beginPath();

ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI);

ctx.fill();

}

/**验证验证码**/

validate: function(code) {

var code = code.toLowerCase();

var v_code = this.options.code.toLowerCase();

console.log(v_code);

if (code == v_code) {

return true;

} else {

this.refresh();

return false;

}

/**生成字母数组**/

function getAllLetter() {

var letterStr = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";

return letterStr.split(",");

}

/**生成一个随机数**/

function randomNum(min, max) {

return Math.floor(Math.random() * (max - min) + min);

}

/**生成一个随机色**/

function randomColor(min, max) {

var r = randomNum(min, max);

var g = randomNum(min, max);

var b = randomNum(min, max);

return "rgb(" + r + "," + g + "," + b + ")";

}

window.GVerify = GVerify;

})(window, document);

// 调用GVerifty

var verifyCode = new GVerify("vCodeImg");

</script>

</html>

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利用canvas绘制带干扰线的验证码

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