The problem: www.tanach.us/Tanach.xml#Intallation .
To show on screen (and print) acceptably texts with vowel points and cantillation (and without them), we need good fonts. It would be nice to be able to force the browser to show a page using a specified font, and there is even a declaration for that in CSS (TODO), but it is not universally supported by modern browsers/operating systems, so the user will need to install a decent font if he is not satisfied with the quality of the pre-installed ones. Font installation is easy, but we need to provide the fonts to install.
We need to be able to install fonts in cross-platform formats.
It happens that there are both a vowel and a cantillation sign under a letter (vowel is printed first in such cases (TODO)). How can we make sure that vowel and cantillation sign do not overlap?
Apple developed font format that allows inclusion (in form of tables) of instructions about combining glyphs. This format used to be called GX, and is now called AAT - Apple Advanced Typography [AAT]. It is currently supported only on macOS (there are plans to support it in HarfBuzz [HarfBuzz] in the future (TODO)), so we can not use it.
SIL International is developing AAT replacement for Windows - Graphite [Graphite]. This format allows inclusion into the font of a program in a special language. This program then chooses and places glyphs. This format is supported on Windows and Linux, but requires installation of programs in addition' to fonts, so we can not use it.