var img = new Image();     img.src = myChart.getDataURL({
      type:"png",     pixelRatio: 2,     backgroundColor: '#fff' }); downloadWeibo(img,"微博平台-事件传播脉络",myChart.getWidth(),myChart.getHeight());

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var  downloadWeibo=function(img,name,width,height){
      console.log(img)     img.οnlοad=function(){
          var canvas=document.createElement("canvas");         console.log($(img).width());         console.log($(img).height());         canvas.width=width*2;         canvas.height=height*2;         var ctx=canvas.getContext('2d');         ctx.drawImage(img,0,0);         canvas.toBlob(function(blob) {
              saveAs(                 blob                 , name+".png"             );         }, "image/png");     } }