微信小程序中的图形验证码

可以在utils中新建一个mcaptcha.js

代码如下：

module.exports = class Mcaptcha {

constructor(options) {

this.options = options;

this.fontSize = options.height * 3 / 6;

this.init();

this.refresh();

}

init() {

this.ctx = wx.createCanvasContext(this.options.el);

this.ctx.setTextBaseline("middle");

this.ctx.setFillStyle(this.randomColor(180, 240));

}

refresh() {

var code = \'\';

var txtArr = [\'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\',0,1,2,3,4,5,6,7,8,9]

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

code += txtArr[this.randomNum(0, txtArr.length)];

}

this.options.createCodeImg = code;

let arr = (code + \'\').split(\'\');

if (arr.length === 0) {

arr = [\'e\', \'r\', \'r\',\'o\',\'r\'];

};

let offsetLeft = this.options.width * 0.6 / (arr.length - 1);

let marginLeft = this.options.width * 0.2;

arr.forEach((item, index) => {

this.ctx.setFillStyle(this.randomColor(0, 180));

let size = this.randomNum(24, this.fontSize);

this.ctx.setFontSize(size);

let dis = offsetLeft * index + marginLeft - size * 0.3;

let deg = this.randomNum(-30, 30);

this.ctx.translate(dis, this.options.height*0.5);

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

this.ctx.fillText(item, 0, 0);

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

this.ctx.translate(-dis, -this.options.height * 0.5);

})

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

this.ctx.strokeStyle = this.randomColor(40, 180);

this.ctx.beginPath();

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

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

this.ctx.stroke();

}

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

this.ctx.fillStyle = this.randomColor(0, 255);

this.ctx.beginPath();

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

this.ctx.fill();

}

this.ctx.draw();

}

validate(code){

var code = code.toLowerCase();

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

console.log(code)

console.log(v_code.substring(v_code.length - 4))

if (code == v_code.substring(v_code.length - 4)) {

return true;

} else {

return false;

}

randomNum(min, max) {

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

}

randomColor(min, max) {

let r = this.randomNum(min, max);

let g = this.randomNum(min, max);

let b = this.randomNum(min, max);

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

}

在对于页面的js中引入mcaptcha.js

var Mcaptcha = require(\'../../../utils/mcaptcha.js\');

/**

* 生命周期函数--监听页面初次渲染完成

onReady: function () {

this.mcaptcha=new Mcaptcha({

el: \'canvas\',

width: 80,

height: 35,

createCodeImg: ""

});

。。。

//刷新验证码

onTap(){

this.mcaptcha.refresh();

//验证验证码

var res = this.mcaptcha.validate(this.data.imgCode);

if (this.data.imgCode == \'\' || this.data.imgCode==null) {

toast.showToast({ title: \'请输入图形验证码\' })

return;

}

if (!res) {

toast.showToast({ title: \'图形验证码错误\' })

return;

}

wxml页面：

</view>

效果：

参考：https://www.jianshu.com/p/064a80a3561a