base64保存下载图片

      exportPng() {
        let _this = this;
        let option = _this.charts.getOption();
    
        console.log(option);
        // 从echarts获取图片
        let imgData = _this.charts.getDataURL({
          type: "png",
          pixelRatio: 2,
          backgroundColor: '#000',
          excludeComponents: ['toolbox', 'dataZoom'],
        });
        _this.downloadFile(`${_this.chartsData.name}.png`, imgData);
      },
      // 下载
      downloadFile(fileName, content) {
        let aLink = document.createElement('a');
        let blob = this.base64ToBlob(content); //new Blob([content]);
    
        let evt = document.createEvent("HTMLEvents");
        evt.initEvent("click", true, true);//initEvent 不加后两个参数在FF下会报错  事件类型，是否冒泡，是否阻止浏览器的默认行为
        aLink.download = fileName;
        aLink.href = URL.createObjectURL(blob);
    
        // aLink.dispatchEvent(evt);
        //aLink.click()
        aLink.dispatchEvent(new MouseEvent('click', {bubbles: true, cancelable: true, view: window}));//兼容火狐
      },
      //base64转blob
      base64ToBlob(code) {
        let parts = code.split(';base64,');
        let contentType = parts[0].split(':')[1];
        let raw = window.atob(parts[1]);
        let rawLength = raw.length;
    
        let uInt8Array = new Uint8Array(rawLength);
    
        for (let i = 0; i < rawLength; ++i) {
          uInt8Array[i] = raw.charCodeAt(i);
        }
        return new Blob([uInt8Array], {type: contentType});
      },

摘抄CSDN博文，以此记录供自己使用！