Save canvas drawing to local image

canvas_to_img.js

function saveCanvas(canvas) {
  var image = canvas.toDataURL('image/png').replace('image/png', 'image/octet-stream');  // here is the most important part because if you dont replace you will get a DOM 18 exception.
  window.location.href = image; // it will save locally
}

function openInNewWindow(canvas) {
  // works in Firefox
  window.open(canvas.toDataURL("image/png"), '_blank');
}

function openOffscreenCanvasInNewWindow(canvas) {
  canvas.convertToBlob().then(blob => {
    const url = URL.createObjectURL(blob);
    window.open(url, '_blank');
  }); 
}