效果图：使用canvas组件对随机的数字字母添加插画背景、干扰线、干扰点

1、在components文件夹下新建securityCode.vue文件，代码：

<template><canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
</template>
<script>export default {name: "securityCode",props: {identifyCode: {type: String,default: "",},fontSizeMin: {type: Number,default: 22,},fontSizeMax: {type: Number,default: 40,},backgroundColorMin: {type: Number,default: 180,},backgroundColorMax: {type: Number,default: 240,},colorMin: {type: Number,default: 50,},colorMax: {type: Number,default: 160,},lineColorMin: {type: Number,default: 40,},lineColorMax: {type: Number,default: 180,},dotColorMin: {type: Number,default: 0,},dotColorMax: {type: Number,default: 255,},contentWidth: {type: Number,default: 120,},contentHeight: {type: Number,default: 40,},},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 = this.randomColor(this.backgroundColorMin,this.backgroundColorMax);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(this.colorMin, this.colorMax);ctx.font =this.randomNum(this.fontSizeMin, this.fontSizeMax) + "px SimHei";let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1));let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5);var deg = this.randomNum(-45, 45);// 修改坐标原点和旋转角度ctx.translate(x, y);ctx.rotate((deg * Math.PI) / 330);ctx.fillText(txt, 0, 0);// 恢复坐标原点和旋转角度ctx.rotate((-deg * Math.PI) / 330);ctx.translate(-x, -y);},drawLine(ctx) {// 绘制干扰线for (let i = 0; i < 3; i++) {ctx.strokeStyle = this.randomColor(this.lineColorMin,this.lineColorMax);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 < 80; 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>

2、在登录页面引入并注册使用组件：

<el-form-item prop="pass" label="验证码" class="row" label-width="150px"><div class="row space-between" style="width: 315px;"><el-input type="text" style="width: 190px;" v-model="inputCode" autocomplete="off"></el-input><div @click="refreshCode()" style="line-height: 0;"><!--验证码组件--><SecurityCode :identifyCode="identifyCode"></SecurityCode></div></div>
</el-form-item>
<el-form-item style="padding-left: 55px;"><el-button type="primary" @click="submitForm()" icon="el-icon-s-custom"><span style="font-size: 15px;letter-spacing: 10px;">登录</span></el-button>
</el-form-item>

<script>//导入组件import SecurityCode from "@/components/securityCode";export default {components: {//注册SecurityCode},data() {identifyCode: "",//随机组合字符串inputCode: "", //text框输入的验证码},mounted() {this.refreshCode();},methods: {//初始化验证码refreshCode() {this.inputCode = ''this.identifyCode = ""; //输入框置空this.makeCode(4); //验证码长度为4},//随机切换验证码makeCode(length) {let code = '';for (let i = 0; i < length; i++) {const r = Math.floor(Math.random() * 36);if (r < 10) {code += r;} else {code += String.fromCharCode(r - 10 + 65);}}this.identifyCode = codelocalStorage.setItem('code', code);console.log(this.identifyCode);},submitForm(formName) {const code = this.inputCode.toLowerCase();const originalCode = localStorage.getItem('code').toLowerCase();if (!code) {this.$message.error('请输入验证码！');return} else if (code !== originalCode) {this.$message.error('验证码输入错误！');this.refreshCode()return}// this.$api.Login({// 	userName: this.ruleForm.user,// 	password: this.ruleForm.pass,// 	systemCode: null,// }).then((data) => {// })},}}
</script>