How to display bold chinese on MacOS's kitty?

[rainzm]

I want to display bold chinese text on MacOS's kitty and I use fira code for ascii char.

As far as I know, symbol_map is mainly designed to display symbols, so it doesn't deal with bold, and I tried, and it is true.

The chinese font will go fallback (Apple CoreText), and as you can see from the kitty --debug-font-fallback command, its font fallback goes to PingFang SC Regular:

And in the figure, U+4f60 bold was also fallback to PingFang SC Regular, even though the font family PingFang SC does indeed have Medium and Semibold, but they were not correctly fallback.

So, does this seem to be a problem with Apple's CoreText? Or is it a problem with how kitty is calling CoreText?

And, given that Apple CoreText is out of control, could kitty provide an additional feature to specify the fallback font?

Or, there are other ways to display bold chinese in kitty?

Thank you very much.

[kovidgoyal]

When looking for the fallback face, kitty passes the bold/italic flags however, IIRC there is no way to get CoreText to respect these. If you know of one, patches are welcome. Relevant code is in create_fallback_face() in core_text.m

[kovidgoyal]

From what I remember of CoreText, you would probably need to first use

CTFontCreateForString() as the existing code does. Then once an appropriate font is found create a font descriptor from the font and then use CTFontDescriptorCreateCopyWithSymbolicTraits() setting the weight and style appropriately. And then create a font from that descriptor, check that the newly created fonts family is the same as the original fallback font and if so use it instead of the original.

[rainzm]

Hi, i add a log in create_fallback_face() on core_text.m file:

And, the kitty log:

Looks like it found PingFangSC-Semibold. But this font is obviously not bold:

And, if I specify bold_font in kitty.conf as PingFang SC Semibold. This display font is bold:

[kovidgoyal]

You dont need to do anything, this is already fixed in master: 752fcb6

[rainzm]

Oh bro, you're amazing! Thank you! Kitty is prefect for me now.