];
      const y2 = bottom * keyboardMatrix[1];
      keyMap.push([key, x1, y1, x2, y2]);
    }
  })
  .catch(err => {
    console.warn(err.stack);
  });

let keyboardHighlightCanvasCtx = null;
new Promise((accept, reject) => {
  const img = new Image();
  img.crossOrigin = 'Anonymous';
  img.src = 'keyboard-highlight.png';
  img.onload = () => {
    const canvas = document.createElement('canvas');
    canvas.width = img.naturalWidth;
    canvas.height = img.naturalHeight;
    const ctx = canvas.getContext(