Fix the REGULAR bit of the fsSelection being set incorrectly

[negset]

Description

This commit resolves the issue of the fsSelection of the OS/2 table not being properly set.

According to Microsoft's documentation, bit 6 (REGULAR) of fsSelection is recommended to be set only when bit 0 (ITALIC) and bit 5 (BOLD) are clear.
However, the current script sets bit 6 (REGULAR) without following this rule (for example, when the font name is XXX-BoldItalic.ttf).

So, I have made changes to ensure that bit 6 (REGULAR) is not set when bit 0 (ITALIC), bit 5 (BOLD), or bit 9 (OBLIQUE) is set.
While the documentation does not specify whether bit 6 (REGULAR) should be cleared when bit 9 (OBLIQUE) is set, I think it should be treated like 0 (ITALIC) and bit 5 (BOLD).

Requirements / Checklist

• Read the Contributing Guidelines
• Verified the license of any newly added font, glyph, or glyph set

What does this Pull Request (PR) do?

How should this be manually tested?

Any background context you can provide?

What are the relevant tickets (if any)?

Screenshots (if appropriate or helpful)

[Finii]

Thanks for the excellent catch!

What do you think about this change instead:

-if len(self.weight_token) == 0 and not b & (ITALIC | BOLD | OBLIQUE):
+if len(self.weight_token) == 0 and not b & (ITALIC | BOLD):

As OBLIQUE is already handled by the (non) empty weight_token. But maybe your code is more clear.
You decide.

Checking if --has-no-italic is handled correctly...
Ah yes, that is handled only later in the concrete name-string generation.

[Finii]

Interestingly Bit 9 (Oblique) is not mentioned 🤔

Bit 6: If bit 6 is set, then bits 0 and 5 must be clear, else the behavior is undefined. Note that, if both bit 0 and bit 5 are clear, that does not give any indication as to whether or not bit 6 will be clear. For example, Arial Light is not the regular style of Arial and would have all bits cleared.

Anyhow. After a ☕ I believe your redundant but more explicit code is better 👍

[Finii]

Thanks again!

I will merge this together with the other 3.0.1 patches.

[Finii]

@allcontributors add @negset for code

[allcontributors]

@Finii

I've put up a pull request to add @negset! 🎉

[negset]

Thank you for merging my pull request!