前端 base64与图片相互转换

base64转图片

如下图：（后端返回的数据）

<img :src="baseImg" >

let baseImg = ""
this.baseImg ="data:image/png;base64," + data?.flowChar

base64转换图片文件

base64ImgtoFile = (dataurl, filename = 'file') => {
  let arr = dataurl.split(',')
  let mime = arr[0].match(/:(.*?);/)[1]
  let suffix = mime.split('/')[1]
  let bstr = atob(arr[1])
  let n = bstr.length
  let u8arr = new Uint8Array(n)
  while (n--) {
    u8arr[n] = bstr.charCodeAt(n)
  }
  return new File([u8arr], `${filename}.${suffix}`, {
    type: mime
  })
}，
// base64编码的图片
baseImg = 'data:image/png;base64,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';
//转换图片文件
const imgFile = base64ImgtoFile(baseImg); 
console.log("imgFile",imgFile);

图片(url)转换base64

getBase64 = (url, callback) => {
  let Img = new Image(),
    dataURL = '';
  Img.src = url + '?v=' + Math.random();
  Img.setAttribute('crossOrigin', 'Anonymous');
  Img.onload = function() {
    let canvas = document.createElement('canvas'),
      width = Img.width,
      height = Img.height;
    canvas.width = width;
    canvas.height = height;
    canvas.getContext('2d').drawImage(Img, 0, 0, width, height);
    dataURL = canvas.toDataURL('image/jpeg', 1); //可选取多种模式
    return callback ? callback(dataURL) : null; //回掉函数获取Base64编码
  };
}

// 调用
let imgUrl=‘https://www.baidu.com/img/bd_logo1.png’
 this.getBase64(imgUrl, dataURL => {
 console.log(dataURL:就是base64了)
});

便捷的图片转化base64

利用 Chrome 浏览器，在 chrome 下新建一个窗口，然后把要转化的图片直接拖入浏览器，打开控制台，点 Source，如下图所示，点击图片，右侧就会显示该图片的 base64 编码