I am designing an Arabic UI font for the Android system. Now I am facing the problem of cut-offs of the top diacritics.
You may need to adapt your winAscent and winDescent values, potentially also the OS/2 typo values. See the details in the Vertical Metrics tutorial.
Thank you for your reply. I just solved this.
Seems Android’s UI doesn’t respond to my setting of the vertical metrics. But when I put the diacritics which are named xxx above in the high place of the metrics will make some differences.