I would prefer to use local programs to make such things. Is there such a open source software that uses Xaw or just plain X window, preferably where the file f

I would prefer to use local programs to make such things. Is there such a open source software that uses Xaw or just plain X window, preferably where the file format is a sequence of PostScript tokens (to make it easy to write a parser for the file format in PostScript (I also wrote a JSON parser in PostScript, so JSON would also work))?