Add hb_font.create_sub_font(font)

[behdad]

Untested.

[behdad]

PTAL.

[anthrotype]

it would be good to confirm that it actually works as intended with a little test in https://github.com/harfbuzz/uharfbuzz/blob/main/tests/test_uharfbuzz.py

even as simple as loading a font, creating the sub font from it, then asserting that the returned value is actually a Font and that its id() is different (font2 is not font) even though the Face the two fonts refer to is the same (e.g. font2.face == font.face)

[behdad]

it would be good to confirm that it actually works as intended with a little test in https://github.com/harfbuzz/uharfbuzz/blob/main/tests/test_uharfbuzz.py

even as simple as loading a font, creating the sub font from it, then asserting that the returned value is actually a Font and that its id() is different (font2 is not font) even though the Face the two fonts refer to is the same (e.g. font2.face == font.face)

Thanks. Done. It fails. I don't know pyx enough to know what I'm doing wrong...

[behdad]

Looks like calling __new__ still calls __cinit__ after. Is that expected?

[behdad]

I suppose we can make the regular constructor create a subfont if it's passed a Font instead of a Face, instead of new API.

[anthrotype]

I'll take a look tomorrow

[behdad]

I managed to move it to constructor and have tests pass.