纯前端vue图形验证码

Posted 2022-11-26 初辰ge

转载自：https://blog.csdn.net/zxh7770/article/details/123906741

创建VerificationCode.vue组件

<template>
  <span class="s-canvas"
        @click="changeCode">
    <canvas id="s-canvas"
            :width="contentWidth"
            :height="contentHeight"></canvas>
  </span>
</template>

<script>
export default 
  data () 
    return 
      identifyCode: ""
    
  ,
  props: 
    identifyCodes: 
      //验证码从该字段中抽取生成
      type: String,
      default: "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    ,
    fontSizeMin: 
      // 字体最小值
      type: Number,
      default: 25
    ,
    fontSizeMax: 
      // 字体最大值
      type: Number,
      default: 35
    ,
    backgroundColorMin: 
      // 验证码图片背景色最小值
      type: Number,
      default: 200
    ,
    backgroundColorMax: 
      // 验证码图片背景色最大值
      type: Number,
      default: 220
    ,
    dotColorMin: 
      // 背景干扰点最小值
      type: Number,
      default: 60
    ,
    dotColorMax: 
      // 背景干扰点最大值
      type: Number,
      default: 120
    ,
    contentWidth: 
      //容器宽度
      type: Number,
      default: 100
    ,
    contentHeight: 
      //容器高度
      type: Number,
      default: 44
    
  ,
  watch: 
    identifyCode () 
      this.drawPic();
    
  ,
  mounted () 
    this.drawPic();
    this.makeCode(this.identifyCodes, 4);
  ,
  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(50, 160); //随机生成字体颜色
      ctx.font =
        this.randomNum(this.fontSizeMin, this.fontSizeMax) + "px SimHei"; //随机生成字体大小
      let x = (i + 1) * ((this.contentWidth - 10) / (this.identifyCode.length + 1));
      let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5);
      var 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) / 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 < 4; i++) 
        ctx.strokeStyle = this.randomColor(100, 200);
        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 < 30; 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();
      
    ,
    /*切换验证码start*/
    changeCode () 
      this.identifyCode = "";
      this.makeCode(this.identifyCodes, 4);
    ,
    makeCode (e, n) 
      for (let i = 0; i < n; i++) 
        this.identifyCode += e[this.randomNum(0, e.length)];
      
      this.$emit("update:changeCode", this.identifyCode);
    
  
;
</script>

使用

<VerificationCode :changeCode.sync="identifyCode"
                  identifyCodes="23456789"
                  :contentHeight="34"></VerificationCode>