code: function calculateScaledFontSize(width, height) {
  	return Math.round(Math.max(12, Math.min(Math.min(width, height) * 0.75, (0.75 * Math.max(width, height)) / 12)));
  }
docs: Calculate a font which works well for the given width and height
  @param width {Number} the width of the image
  @param height {Number} the height of the image
  @returns {Number} fontSize