uniapp前端生成图形验证码校验

1.复制相关代码添加 mcaptcha.js 文件

// mcaptcha.js

export class Mcaptcha {
    constructor(options) {
        this.options = options;
        this.fontSize = options.height * 3 / 6;
        this.init();
        this.refresh();
    }
    init() {
        this.ctx = uni.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 + ")";
    }
}

22、在使用图形验证码的页面引入并使用

引入

import { Mcaptcha  } from '@/utils/mcaptcha'

初始化

onReady() {
   this.mcaptcha = new Mcaptcha({
     el: 'canvas',
     width: 80,
     height: 35,
     createCodeImg: ""
   });
 },

页面展示

<view class="code-img-wrapper" @click="updateImageCode">
  <canvas style="width:220rpx;height:86rpx;" canvas-id="canvas"></canvas>
</view>

 <input type="text" v-model="graphicVerifyCode" placeholder="请填写">
        <view class="" @click="submit">
            提交
        </view>
        
data() {
            return {
                mcaptcha:null,
                graphicVerifyCode:''
            }
        },

刷新图形验证码

// 刷新验证码
updateImageCode() {
  this.mcaptcha.refresh()
},

检验

// 提交前校验图形验证码
submit() {
  if(!this.form.graphicVerifyCode) {
    return uni.showToast({ title: '请输入图形验证码' })
  }
  let validate = this.mcaptcha.validate(this.form.graphicVerifyCode)
  if(!validate) {
    return uni.showToast({ title: '图形验证码错误' })
  }
  ...
}