Take screenshot from canvas?

Hi, I would like to take a screenshot from the rendered canvas but when I tried to apply to toDataURL() to get the base64, the result is completely blank. In addition, I already took a look at the ParaView Glance’s source code covering the screenshot feature but I am still very confused at the part img.addEventListener('load', () => {}. Here is my source code, hope to reiceve the answer from you. Thanks. @jourdain

function convertCanvasToImage(canvas) {
    var image = new Image();
    image.src = canvas.toDataURL("image/png");
    return image;
}
base64 = convertCanvasToImage($('#3d canvas').get(0)).src;

[jourdain]

Then just trigger a render() to allow the promise to resolve.

[jourdain]

The promise content will have the data you are looking for.