code: @SuppressWarnings("WeakerAccess")
  	public void registerFont(String fontName, File fontFile) {
  		if (!fontFile.exists())
  			throw new IllegalArgumentException("Font " + fontFile + " does not exist!");
  		FontEntry entry = new FontEntry();
  		entry.overrideName = fontName;
  		entry.file = fontFile;
  		fontFiles.add(entry);
  	}
docs: Register a font.
  
  @param fontName
  the name of the font to use. If null, the name is taken from the
  font.
  @param fontFile
  the font file. This file must exist for the live time of this
  object, as the font data will be read lazy on demand