Textfont that decomposes Korean

I found my problem with Korean textfonts decomposing. If I use “Times New Roman” instead of Arial or the System font then it will decompose with file names.
Suggestions.

What do you mean “decompose with file names” ?

As far as I can tell, Times New Roman doesn’t support Korean so the operating system will be falling back to a different font anyway.

Is there a reason why you are trying to use Times New Roman or Arial?

Kevin.
The way I tell if a font supports Korean is graphically. I like fonts with serifs, and Times New Roman has serifs. For the test, I have a little textarea with
???
as the text and it’s next to the font selector, and it will match the style for the rest of the changes. I don’t look for Unicode code-points, but I could do that, if I could figure out how with XOJO.
How can I do that?
Where is an explanation (whatever system you choose) of detecting if a font supports codepoints?

Michel.
Sorry that I used a word wrong. The reference books I have for Korean don’t explain with Unicode terms like Normalize. They are only 20 years old.
Unicode.org doesn’t explain it any better.

What I mean by decompose.
Normalized Korean: ??? This is also conjoined.
Concatenated Korean : ??? I thought this was decomposed but that is not correct. I am not sure what decomposed and Korean is.
The more correct words might by conjoined ?? (Jamo).

So. If I have a filename (any base type like .jpg .mp3 .txt) such as ???.txt and am using a font (as Kevin wrote) that doesn’t support Korean, then the name becomes

???.txt

This is apparently only concatenated and not conjoined. It is the
I also don’t understand why this happens only to filenames in textareas when the font is not supporting Korean. It also happens in strict UTF8 text files when I copy them from Mac to PC. They literally break down.

My conclusion is this is an Mac OS problem and not XOJO. I have no idea where to go with this problem.
Who do I tell?
Suggestions?

As a quick test I pasted that text into a TextField and TextArea and set the font to Times New Roman. As far as I could tell, the text appeared correctly using Xojo 2017r3 running on my Mac (10.9.5).
Could there be other (null) characters in the text that causes display issues when the operating system falls back to a different font?

As for finding out if a font contains Korean (Hangul), our app looks at the Unicode script ranges and the code pages set within the font. We have our own text layout engine so don’t go through macOS or MS-Windows for any this. It might be worthwhile you looking at the MBS plugins. A quick look seems to indicate you might be able to find a solution using NSFontMBS (Mac) and WindowsFontFamilyMBS.

I want to clarify why I am interested in this. On a Mac the UnNormalizing of a Korean filename isn’t a problem. It is only when I copy a filename specifically sound and image files (not text) with Korean normalized characters in a text file to a PC that UnNormalizes and becomes umm permanent.

Thanks Kevin.

I don’t know how to answer that. It is the filename’s nativePath or just the name itself.
I don’t know the binary enough
This also happens when I take a text file from a Mac to a PC. It doesn’t happen with anything umm higher like RTF.
I think it also happens with a ini file but I can’t remember.

I did my report of filenames in a textarea with TimesNewRoman. It should lots of UNnormalized names.
I only copied the last one because it shows here correctly.

This is the same list as a screenshot and the file is on the bottom.

About MBS. I probably can, but that is an extra right now.

Update:
Times New Roman does not support Korean. If I have Korean Hangeul characters in the TextEdit.App and try to change it to TimesNewRoman, then it automatically changes to AppleMyungJo.

You mentioned an issue with PC. You should know that macOS is able to switch to another font to support a given set of characters, but Windows is not able of such feat. You must have a Hangul supporting font to display Korean correctly.

You are quite correct that a PC doesn’t. The font I chose is called “Beat My Guest”