登录实现图片验证码

背景

登录基本是很多前端网站都需要的功能了吧，验证码防止“注册机”也是比较常见的了。这里用vue来实实现下登录的图片验证码功能，当然普通的H5项目也是可以实现，原理是相通的。

Vue实现图片验证码

封装自定义的图片验证码组件IdentifyCode

API参考

在这里插入图片描述

代码

<template><div class="s-canvas"><canvas id="s-canvas" :width="contentWidth" :height="contentHeight"/></div>
</template>
<script>export default{name: 'identify-code',//接受父组件的传值props: {//展示的图片验证码identifyCode: {type: String,default: '1234'},//字体大小，最小值fontSizeMin: {type: Number,default: 16},//字体大小，最大值fontSizeMax: {type: Number,default: 40},//背景颜色色值最小值，最小为backgroundColorMin: {type: Number,default: 180},//背景颜色色值最大值，最大为255backgroundColorMax: {type: Number,default: 240},//字体颜色色值最小值，最小为0colorMin: {type: Number,default: 50},//字体颜色色值最大值，最大为255colorMax: {type: Number,default: 160},//干扰线颜色色值最小值，最小为0lineColorMin: {type: Number,default: 40},//干扰线颜色色值最大值，最大为255lineColorMax: {type: Number,default: 180},//干扰点颜色色值最小值，最小为0dotColorMin: {type: Number,default: 0},//干扰点颜色色值最大值，最大为255dotColorMax: {type: Number,default: 255},//画布（图片）宽度contentWidth: {type: Number,default: 112},//画布（图片）高度contentHeight: {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 + ')'},//利用canvas，生成图片验证码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)},//画验证码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 / 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 < 8; 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 < 100; 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()}},//初始生成验证码mounted () {this.drawPic()}}
</script>

使用IdentifyCode组件生成验证码

<template><!--    图片验证码    --><div @click="refreshCode"><identify-code:identifyCode="identifyCode":contentWidth="150":contentHeight="50":fontSizeMin="50"/></div>
</template>
<script>import IdentifyCode from '../components/IdentifyCode'export default {name: 'login',components: {'identify-code': IdentifyCode,},data: () => ({//生成验证码的字符范围identifyCodes: "ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz0123456789",//生成的验证码identifyCode: "",}),methods: {//生成随机数randomNum(min, max) {return Math.floor(Math.random() * (max - min) + min);},//刷新验证码refreshCode() {this.identifyCode = "";this.makeCode(this.identifyCodes, 4);},//生成验证码，l为生成验证码的长度makeCode(o, l) {for (let i = 0; i < l; i++) {//随机字符串拼接this.identifyCode += this.identifyCodes[this.randomNum(0, this.identifyCodes.length)];}}},mounted() {this.identifyCode = "";this.makeCode(this.identifyCodes, 4);},};
</script>