vue3 登录添加图形验证码

1. 新增组件 IdentifyCode.vue ，使用canvas绘制验证码内容：

<template>
  <div class="s-canvas" @click="refreshCode">
    <canvas
      id="s-canvas"
      :width="contentWidth"
      :height="contentHeight"
    ></canvas>
  </div>
</template>
<script setup>
import { ref, onMounted, watch } from "vue";
 
let curIdentifyCode = ref("");
 
const props = defineProps({
  identifyCode: {
    type: String,
    default: "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",
  },
  fontSizeMin: {
    type: Number,
    default: 16,
  },
  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: 38,
  },
});
 
watch(curIdentifyCode, () => {
  drawPic();
});
 
const emit = defineEmits(["updateIdentifyCode"]);
 
// 生成一个随机数
const randomNum = (min, max) => {
  return Math.floor(Math.random() * (max - min) + min);
};
// 生成一个随机的颜色
const randomColor = (min, max) => {
  let r = randomNum(min, max);
  let g = randomNum(min, max);
  let b = randomNum(min, max);
  return "rgb(" + r + "," + g + "," + b + ")";
};
const drawPic = () => {
  let canvas = document.getElementById("s-canvas");
  let ctx = canvas.getContext("2d");
  ctx.textBaseline = "bottom";
  // 绘制背景
  ctx.fillStyle = randomColor(
    props.backgroundColorMin,
    props.backgroundColorMax
  );
  ctx.fillRect(0, 0, props.contentWidth, props.contentHeight);
  // 绘制文字
  for (let i = 0; i < curIdentifyCode.value.length; i++) {
    drawText(ctx, curIdentifyCode.value[i], i);
  }
  drawLine(ctx);
  drawDot(ctx);
};
const drawText = (ctx, txt, i) => {
  ctx.fillStyle = randomColor(props.colorMin, props.colorMax);
  ctx.font = randomNum(props.fontSizeMin, props.fontSizeMax) + "px SimHei";
  let x = (i + 1) * (props.contentWidth / (curIdentifyCode.value.length + 1));
  let y = randomNum(props.fontSizeMax, props.contentHeight - 5);
  let deg = 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);
};
const drawLine = (ctx) => {
  // 绘制干扰线
  for (let i = 0; i < 8; i++) {
    ctx.strokeStyle = randomColor(props.lineColorMin, props.lineColorMax);
    ctx.beginPath();
    ctx.moveTo(
      randomNum(0, props.contentWidth),
      randomNum(0, props.contentHeight)
    );
    ctx.lineTo(
      randomNum(0, props.contentWidth),
      randomNum(0, props.contentHeight)
    );
    ctx.stroke();
  }
};
const drawDot = (ctx) => {
  // 绘制干扰点
  for (let i = 0; i < 100; i++) {
    ctx.fillStyle = randomColor(0, 255);
    ctx.beginPath();
    ctx.arc(
      randomNum(0, props.contentWidth),
      randomNum(0, props.contentHeight),
      1,
      0,
      2 * Math.PI
    );
    ctx.fill();
  }
};
 
const refreshCode = () => {
  curIdentifyCode.value = "";
  makeCode(props.identifyCode, 4);
};
const makeCode = (o, l) => {
  for (let i = 0; i < l; i++) {
    curIdentifyCode.value += o[randomNum(0, o.length)];
  }
  // console.log(curIdentifyCode.value);
  emit("updateIdentifyCode", curIdentifyCode.value);
};
 
onMounted(() => {
  drawPic();
  refreshCode();
});
 
defineExpose({
  refreshCode,
});
</script>
 

2. 引入组件并使用：

<div class="login-box tx-c pd-t-30">
  <div>用户登录</div>
  <div class="form-box flex-row just-c">
    <el-form
      class="mr-t-40"
      ref="loginForm"
      :model="state.loginForm"
      :rules="state.loginFormRules"
    >
      <el-form-item prop="username">
        <el-input
          placeholder="请输入正确的用户名"
          v-model.trim="state.loginForm.username"
        >
          <template #prefix>
            <img src="@/assets/images/login/yonghu.png" alt="" />
          </template>
        </el-input>
      </el-form-item>
      <el-form-item prop="password">
        <el-input
          type="password"
          placeholder="请输入正确的账号匹配密码"
          v-model.trim="state.loginForm.password"
        >
          <template #prefix>
            <img src="@/assets/images/login/mima.png" alt="" />
          </template>
        </el-input>
      </el-form-item>
      <el-form-item prop="identifyCode">
        <el-input
          placeholder="请输入验证码"
          v-model.trim="state.loginForm.identifyCode"
        >
          <template #prefix>
            <img src="@/assets/images/login/code.png" alt="" />
          </template>
        </el-input>
        <IdentifyCode
          ref="identify"
          class="code-box"
          :contentWidth="120"
          :contentHeight="60"
          @updateIdentifyCode="setIdentifyCode"
        ></IdentifyCode>
      </el-form-item>
 
      <el-button type="primary" class="mr-t-30" @click="loginValidator"
        >登录
      </el-button>
    </el-form>
  </div>
</div>

import IdentifyCode from "@/components/IdentifyCode.vue";
 
const identify = ref(null);
const validateIdentifyCode = (rule, value, callback) => {
  if (value !== curIdentifyCode.value) {
    callback(new Error("验证码错误!"));
    state.loginForm.identifyCode = "";
    identify.value.refreshCode();
  } else {
    callback();
  }
};
 
const state = reactive({
  loginForm: {
    username: "",
    password: "",
    identifyCode: "",
  },
  loginFormRules: {
    username: [{ required: true, message: "请输入用户名", trigger: "blur" }],
    password: [{ required: true, message: "请输入密码", trigger: "blur" }],
    identifyCode: [
      { required: true, message: "请输入验证码", trigger: "blur" },
      { validator: validateIdentifyCode, trigger: "blur" },
    ],
  },
});
let curIdentifyCode = ref("");
 
const loginForm = ref(null);
 
// 登录校验
const loginValidator = () => {
  loginForm.value.validate((valid) => {
    if (valid) {
      login();
    }
  });
};
 
// 登录
const login = async () => {
  const { username, password } = state.loginForm;
  const params = {
    username,
    password,
    type: "1",
  };
  const res = await $api.login(params);
  const { code, data } = res;
  if (code === 0 && data) {
    sessionStorage.setItem("isLogin", true);
    sessionStorage.setItem("token", data);
    router.replace("/home");
  } else {
    identify.value.refreshCode();
  }
};
 
const setIdentifyCode = (val) => {
  curIdentifyCode.value = val;
};

<style scoped>
.code-box {
  position: absolute;
  right: 0;
  top: 0;
  cursor: pointer;
}
</style>

3. 组件配置项：

属性	类型	描述
identifyCode	String	验证码取值内容
fontSizeMin	Number	字体最小值
fontSizeMax	Number	字体最大值
backgroundColorMin	Number	背景颜色rgb的最小值
backgroundColorMax	Number	背景颜色rgb的最大值
colorMin	Number	字体颜色rgb的最小值
colorMax	Number	字体颜色rgb的最大值
lineColorMin	Number	干扰线颜色rgb的最小值
lineColorMax	Number	干扰线颜色rgb的最大值
dotColorMin	Number	干扰点颜色rgb的最小值
dotColorMax	Number	干扰点颜色rgb的最大值
contentWidth	Number	画布宽度
contentHeight	Number	画布高度