Tegaki.open({
  // when the user clicks on Finish
  onDone: function() {
    var w = window.open('');
    
    // Tegaki.flatten() returns a <canvas>
    Tegaki.flatten().toBlob(
      function(b) { w.location = URL.createObjectURL(b); },
      'image/png'
    );
  },
  // when the user clicks on Cancel
  onCancel: function() { console.log('Closing...')},
  
  // initial canvas size
  width: 380,
  height: 380
});