22、vue實現隨機四位數驗證碼

效果圖：

1、新建生成驗證碼的組件Sidentify.vue(代碼如下):

<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: 25
    },
    fontSizeMax: {
      type: Number,
      default: 30
    },
    backgroundColorMin: {
      type: Number,
      default: 255
    },
    backgroundColorMax: {
      type: Number,
      default: 255
    },
    colorMin: {
      type: Number,
      default: 0
    },
    colorMax: {
      type: Number,
      default: 160
    },
    lineColorMin: {
      type: Number,
      default: 100
    },
    lineColorMax: {
      type: Number,
      default: 255
    },
    dotColorMin: {
      type: Number,
      default: 0
    },
    dotColorMax: {
      type: Number,
      default: 255
    },
    contentWidth: {
      type: Number,
      default: 112
    },
    contentHeight: {
      type: Number,
      default: 31
    }
  },
  methods: {
    // 生成一個隨機數
    randomNum(min, max) {
      return Math.floor(Math.random() * (max - min) + min);
    },
    // 生成一個隨機的顏色
    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";
      // 繪制背景
      ctx.fillStyle = this.randomColor(
        this.backgroundColorMin,
        this.backgroundColorMax
      );
      ctx.fillRect(0, 0, this.contentWidth, this.contentHeight);
      // 繪制文字
      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);
      // 修改坐標原點和旋轉角度
      ctx.translate(x, y);
      ctx.rotate(deg * Math.PI / 180);
      ctx.fillText(txt, 0, 0);
      // 恢復坐標原點和旋轉角度
      ctx.rotate(-deg * Math.PI / 180);
      ctx.translate(-x, -y);
    },
    drawLine(ctx) {
      // 繪制干擾線
      for (let i = 0; i < 5; 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) {
      // 繪制干擾點
      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>
<style scoped>
.s-canvas {
  height: 38px;
}
.s-canvas canvas {
  margin-top: 1px;
  margin-left: 8px;
}
</style>

2、在需要的頁面引入該組件並使用：

 

   <el-form-item prop="code">

      <el-input v-model="form.code" autocomplete="off" placeholder="請輸入驗證碼"  style="width:150px;float:left"></el-input>
              <div class="login-code" @click="refreshCode">
                <!--驗證碼組件-->
                <Sidentify :identifyCode="identifyCode" />
              </div>
            </el-form-item>

import Sidentify from "../utils/Sidentify.vue";
components: {
Sidentify
},
data(){
  return{

     identifyCodes: "1234567890",

     identifyCode: "",

 }
}

3、獲取驗證碼的方法：

methods:{

 
           
             //驗證碼 
            
           
             randomNum(min, max) { 
            
           
                return Math.floor(Math.random() * (max - min) + min); 
            
           
             }, 
            
           
 
           
             refreshCode() { 
            
           
                this.identifyCode = ""; 
            
           
                this.makeCode(this.identifyCodes, 4); 
            
           
             }, 
            
           
             makeCode(o, l) { 
            
           
                for (let i = 0; i < l; i++) { 
            
           
                 this.identifyCode += this.identifyCodes[ 
            
           
                 this.randomNum(0, this.identifyCodes.length) 
            
           
                ]; 
            
           
             } 
            
           
                console.log(this.identifyCode); 
            
           
             } 
            
          

},

created() {

  //初始化驗證碼

  this.refreshCode();

},

mounted() {

  this.identifyCode = "";

  this.makeCode(this.identifyCodes, 4);

}