Improved type hints for ImageDraw and ImageFont

[AsfhtgkDavid]

Fixes #typing

Changes proposed in this pull request:

• Changed some str type to Literal for more specificity

[radarhere]

Approved, but I'd like to know what @hugovk thinks of Anchor, Align and Direction as well.

I'm not sure if a list of 24 Anchor values is helpful or not. I would imagine either you already know what value you want, or you need to go and look at https://pillow.readthedocs.io/en/stable/handbook/text-anchors.html.

[AsfhtgkDavid]

I think this type hinting is in line with The zen of python's principle ‘Explicit is better than implicit’.

[hugovk]

How disruptive do you think this will be?

Does this mean people using the old string versions will start getting potentially lots of type hint errors, and will need to switch to the new literals or add type: ignore[arg-type]?

Is there any performance impact?

[radarhere]

Does this mean people using the old string versions will start getting potentially lots of type hint errors, and will need to switch to the new literals or add type: ignore[arg-type]?

from PIL import ImageFont
font = ImageFont.load_default()
font.getbbox("test", anchor="la")

would continue to work without a problem, but

anchor = "la"
font.getbbox("test", anchor=anchor)

would raise a type hint error, yes.

Is there any performance impact?

I don't expect so. I would say that only type hinting code has been modified here.

How disruptive do you think this will be?

The type hints being changed were added in 11.0.0, so users who have updated in the last six months and use type hinting would be affected. If there is a feeling that this is troublesome to people who are excitedly getting on board with the idea of using type hints in Pillow, then I'm personally with closing this for that reason.