I am trying to typeset a poem with XeLaTeX using the IranNastaliq font, and I am running into problems with the glyphs rendered for many words. I have a PDF file I rendered from the same source tex file several years ago that is free of these problems.
A minimal example is shown below:
%!TEX TS-program-xelatex
%!TEX encoding = UTF-8 Unicode
\documentclass{article}
\usepackage{fontspec}
\newfontfamily\farsifont[Script=Arabic,Scale=10]{IranNastaliq}
\begin{document}
\farsifont
{\huge نگار}
\end{document}
This produces the image on the left on my current setup (MacTeX BasicTeX 2014). The image on the right, on the other hand, is what gets rendered in other programs, such as TextEdit, and what I had rendered in the past using XeLaTeX on an older computer (also OS X).
What could be causing this problem? How would I debug this?