用canvas实现验证码的绘制

login.vue主文件

<template>
    <div class="login-wrapper">
        <img src="../../assets/images/logo.png" class="logo" />
        <div class="login-box">
            <ul class="login-title-list">
                <li class="login-title-item active">账号登录</li>
                <li class="login-title-item">二维码登录</li>
            </ul>
            <div class="login-body">
                <el-form
                    autocomplete="off"
                    :model="loginForm"
                    :rules="loginRules"
                    ref="loginForm"
                    label-position="left"
                    label-width="0px"
                    class="card-box login-form"
                >
                    <el-form-item prop="username">
                        <svg-icon icon-class="user" class="icon-svg" />
                        <el-input placeholder="请输入邮箱" type="text" v-model="loginForm.username" />
                    </el-form-item>
                    <el-form-item prop="password">
                        <svg-icon icon-class="password" class="icon-svg" />
                        <el-input placeholder="请输入密码" type="password" v-model="loginForm.password" />
                    </el-form-item>
                    <el-form-item prop="verifycode" class="form-item-captcha">
                        <el-input placeholder="请输入验证码" type="captcha" v-model="loginForm.verifycode" />
                        <span @click="refreshCode" class="yzm">
                            <s-identify :identifyCode="identifyCode"></s-identify>
                        </span>
                    </el-form-item>
                    <el-form-item class="login-wrap">
                        <el-button type="primary" :loading="loading" style="100%;" @click="handleLogin"
                            >登录</el-button
                        >
                    </el-form-item>
                </el-form>
                <div class="login-footer">
                    <el-checkbox v-model="rememberPassword">记住密码</el-checkbox>
                    <span>忘记密码?</span>
                </div>
            </div>
        </div>
    </div>
</template>

<script>
import { mapState } from 'vuex';
import SIdentify from './identify.vue';
import { encryptDes } from '../../assets/js/utils/des';

export default {
    name: 'Login',
    components: {
        SIdentify
    },
    data() {
        // 验证码自定义验证规则
        const validateVerifycode = (rule, value, callback) => {
            let newVal = value.toLowerCase();
            let identifyStr = this.identifyCode.toLowerCase();
            if (newVal === '') {
                callback(new Error('请输入验证码'));
            } else if (newVal !== identifyStr) {
                callback(new Error('验证码不正确!'));
            } else {
                callback();
            }
        };
        return {
            loginForm: {
                username: '',
                password: '',
                verifycode: ''
            },
            identifyCodes: '1234567890ABCDEFGHIGKLMNOPQRSTUVWXYZ',
            identifyCode: '',
            rememberPassword: true,
            loading: false,
            loginRules: {
                username: [{ required: true, trigger: 'blur', message: '账号不能为空' }],
                password: [
                    { required: true, message: '请输入密码', trigger: 'blur' },
                    { min: 6, message: '密码长度最少为6位', trigger: 'blur' }
                ],
                verifycode: [{ required: true, trigger: 'blur', validator: validateVerifycode }]
            }
        };
    },
    methods: {
        // 生成随机数
        randomNum(min, max) {
            return Math.floor(Math.random() * (max - min) + min);
        },
        // 切换验证码
        refreshCode() {
            this.identifyCode = '';
            this.makeCode(this.identifyCodes, 4);
        },
        // 生成四位随机验证码
        makeCode(o, l) {
            for (let i = 0; i < l; i++) {
                this.identifyCode += this.identifyCodes[this.randomNum(0, this.identifyCodes.length)];
            }
        },
        handleLogin() {
            this.$refs.loginForm.validate(valid => {
                if (valid) {
                    this.loading = true;
                    const loginParams = {
                        loginUserId: this.loginForm.username,
                        password: encryptDes(this.loginForm.password)
                    };
                    this.$store.dispatch('login', loginParams).then(res => {
                        this.loading = false;
                        if (res.status === 200) {
                            this.$store.commit('SET_USER_INFO', res.data.onlineUserInfo);
                            this.$router.push({ path: '/' });
                        }
                    });
                } else {
                    return false;
                }
            });
        }
    },
    mounted() {
        // 验证码初始化
        this.identifyCode = '';
        this.makeCode(this.identifyCodes, 4);
    }
};
</script>

identify.vue文件

<template>
    <div class="s-canvas">
        <canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
    </div>
</template>
<script>
export default {
  name: 'SIdentify',
  props: {
    identifyCode: {
      type: String,
      default: '1234'
    },
    fontSizeMin: {
      type: Number,
      default: 28
    },
    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: 112
    },
    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);
      let 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) / 270);
      ctx.fillText(txt, 0, 0);
      // 恢复坐标原点和旋转角度
      ctx.rotate((-deg * Math.PI) / 270);
      ctx.translate(-x, -y);
    },
    drawLine(ctx) {
      // 绘制干扰线
      for (let i = 0; i < 2; 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 < 20; 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>