src/charts/helpers/export.js
function handleImageLoad(canvas, filename, e) {
        e.preventDefault();

        downloadCanvas(drawImageOnCanvas(this, canvas), filename);
    }
function handleImageLoad(canvas, filename, e) {
        e.preventDefault();

        downloadCanvas(drawImageOnCanvas(this, canvas), filename);
    }
function handleImageLoad ( canvas , filename , e ) { e . preventDefault ( ) ; downloadCanvas ( drawImageOnCanvas ( this , canvas ) , filename ) ; }
Handles on load event fired by img.onload, this=img
@param  {object} canvas TYPE: el <canvas>
@param  {string} filename
@param  {object} e
Handles on load event fired by img . onload this = img