text: function toRadian(angle) {
    return angle * Math.PI / 180.0;
  };
  
  function convertCanvasToImage(canvas) {
    var image = document.createElement('img');
    image.src = canvas.toDataURL();
    image.style = canvas.style;
    canvas.parentElement.replaceChild(image, canvas);
    return image;
  }
  
  function resizeCanvas(canvas) {
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
  
  }
  