public static void writePS(Tree t, List<String> ruleNames,
							   String fileName,
							   String fontName, int fontSize)
		throws IOException
	{
		String ps = getPS(t, ruleNames, fontName, fontSize);
		FileWriter f = new FileWriter(fileName);
		BufferedWriter bw = new BufferedWriter(f);
		try {
			bw.write(ps);
		}
		finally {
			bw.close();
		}
	}
Save this tree in a postscript file using a particular font name and size
tool/src/org/antlr/v4/gui/Trees.java