vue实现登录页面的验证码以及验证过程解析(面向新手)

<template>
 <div class="s-canvas">
  <canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
 </div>
</template>
<script>
export default{
 name: 'SIdentify',
 props: {
  identifyCode: { // 默认注册码
   type: String,
   default: '1234'
  },
  fontSizeMin: { // 字体最小值
   type: Number,
   default: 25
  },
  fontSizeMax: { // 字体最大值
   type: Number,
   default: 35
  },
  backgroundColorMin: { // 验证码图片背景色最小值
   type: Number,
   default: 200
  },
  backgroundColorMax: { // 验证码图片背景色最大值
   type: Number,
   default: 220
  },
  dotColorMin: { // 背景干扰点最小值
   type: Number,
   default: 60
  },
  dotColorMax: { // 背景干扰点最大值
   type: Number,
   default: 120
  },
  contentWidth: { // 容器宽度
   type: Number,
   default: 90
  },
  contentHeight: { // 容器高度
   type: Number,
   default: 38
  }
 },
 methods: {
  // 生成一个随机数
  randomNum (min, max) {
   return Math.floor(Math.random() * (max - min) + min)
  },
 
  // 生成一个随机的颜色
  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 + ')'
  },
 
  drawPic () {
   let canvas = document.getElementById('s-canvas')
   let ctx = canvas.getContext('2d')
   ctx.textBaseline = 'bottom'
   // 绘制背景
   ctx.fillStyle = '#e6ecfd'
   ctx.fillRect(0, 0, this.contentWidth, this.contentHeight)
   // 绘制文字
   for (let i = 0; i < this.identifyCode.length; i++) {
    this.drawText(ctx, this.identifyCode[i], i)
   }
   this.drawLine(ctx)
   this.drawDot(ctx)
  },
 
  drawText (ctx, txt, i) {
   ctx.fillStyle = this.randomColor(50, 160) // 随机生成字体颜色
   ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + 'px SimHei' // 随机生成字体大小
   let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1))
   let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5)
   var deg = this.randomNum(-30, 30)
   // 修改坐标原点和旋转角度
   ctx.translate(x, y)
   ctx.rotate(deg * Math.PI / 180)
   ctx.fillText(txt, 0, 0)
   // 恢复坐标原点和旋转角度
   ctx.rotate(-deg * Math.PI / 180)
   ctx.translate(-x, -y)
  },
 
  drawLine (ctx) {
   // 绘制干扰线
   for (let i = 0; i < 4; i++) {
    ctx.strokeStyle = this.randomColor(100, 200)
    ctx.beginPath()
    ctx.moveTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight))
    ctx.lineTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight))
    ctx.stroke()
   }
  },
 
  drawDot (ctx) {
   // 绘制干扰点
   for (let i = 0; i < 30; i++) {
    ctx.fillStyle = this.randomColor(0, 255)
    ctx.beginPath()
    ctx.arc(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI)
    ctx.fill()
   }
  }
 },
 watch: {
  identifyCode () {
   this.drawPic()
  }
 },
 mounted () {
  this.drawPic()
 }
}
</script>

<el-form-item prop="code">
  <el-input type="text" v-model="formLogin.code" placeholder="- - - -">
   <template slot="prepend">验证码</template>
   <template slot="append">
    <div class="login-code" @click="refreshCode">
     <Identify :identifyCode="identifyCode"></Identify>
    </div>
   </template>
  </el-input>
 </el-form-item>

<el-button-group>
        <el-button style="width:100%" @click="submit" type="primary">登录</el-button>
 </el-button-group>

import Identify from './identify'

// 表单
   formLogin: {
    username: "",
    password: "",
    code: ""
   },
   identifyCodes: '1234567890abcdefjhijklinopqrsduvwxyz',
   identifyCode: '',
   // 校验
   rules: {
    username: [
     { required: true, message: "请输入用户名", trigger: "blur" }
    ],
    password: [{ required: true, message: "请输入密码", trigger: "blur" }],
    code: [{ required: true, message: "请输入验证码", trigger: "blur" }]
   }

mounted () {
  // 初始化验证码
  this.identifyCode = ''
  this.makeCode(this.identifyCodes, 4)
 },

 // 引入验证接口
...mapActions("d2admin/account", ["login"]),
    // 重置验证码
  refreshCode () {
   this.identifyCode = ''
   this.makeCode(this.identifyCodes, 4)
  },
  makeCode (o, l) {
   for (let i = 0; i < l; i++) {
    this.identifyCode += this.identifyCodes[this.randomNum(0, this.identifyCodes.length)]
   }
  },
  randomNum (min, max) {
   return Math.floor(Math.random() * (max - min) + min)
  },
  /**
  * @description 提交表单
  */
  // 提交登录信息
  submit() {
    if (this.formLogin.code.toLowerCase() !== this.identifyCode.toLowerCase()) {
    this.$message.error('请填写正确验证码')
    this.refreshCode()
    return
   }
   this.$refs.loginForm.validate(valid => {
    if (valid) {
     // 登录
     // 注意 这里的演示没有传验证码
     // 具体需要传递的数据请自行修改代码
     this.login({
      vm: this,
      username: this.formLogin.username,
      password: this.formLogin.password
     });
    } else {
     // 登录表单校验失败
     this.$message.error("表单校验失败");
    }
   });
  }