Need: a way to store these UFO-specific, glyph-specific settings.

Goal: avoid storing data in .glif files themselves, as this could mess with the clarity of version control history (e.g. changing the extension visualization would appear as a change to the glyph, when it is merely a layer of additional information.

Rough plan: I think that a new .plist file can be created and inserted into a UFO, in order to store information such as this. This would be distinct from storing extension-specific preferences because the offset values wouldn't be globally applicable.

Question: Is it true that one could make a .plist file and store data within it? E.g. could I make viz_settings.plist and store a dictionary of glyphs & their offset settings within it? I'm having a hard time finding documentation of this type of thing, but I wouldn't want to mess with it if it is somehow a bad idea.

Thanks for any insights!

the lib: font.lib and glyph.lib with reversed domain lib key, a lib can handle numbers, strings, lists and dicts.

if you have more complex data to store you can also use the data folder.

However, font.lib might be better. I think that probably, font.data is the most appealing solution, but still relatively unclear on how to use. But, it's probably the kind of thing that will be clearer with experimentation. Probably, it would be simpler if added to FontParts.

import plistlib

# write to .plist file

myCustomData = {
    'A' : 100,
    'B' : True,
    'C' : 'hamburgefons',
    'D' : [10, 20, 30, 50],
}

plistPath = 'myFolder/test.plist'

with open(plistPath, 'wb') as f: 
    plistlib.dump(myCustomData, f)

# read from .plist file

with open(plistPath, 'rb') as f: 
    myData = plistlib.load(f)

print(myData)

Awesome, thanks for making it so clear! Okay, yes, this is very easy to work with, now.