相当于[NSFont fontWithName]的CoreText

Question

In our app we are storing fonts for custom objects as strings containing the font name (as retrieved from the font panel) and instantiate fonts using

+ (NSFont *)fontWithName:(NSString *)fontName

Now when loading or importing files we'd like to check whether the font name will actually resolve on the current system.

Due to certain design restrictions we need to perform the check in plain old C/C++, ie these days using CoreText .

However, there doesn't seem to exist an equivalent CoreText API call working similarly to fontWithName: :

• CTFontCreateWithName always returns a font as it uses a fallback strategy
• CTFontCopyFullName appears to use different names than wha is accepted/used by NSFont ..?

So basically the question is:
How can we use CoreText functionality to check whether a font exists on the current system and the font can be instantiated successfully using [NSFont fontWithName:] later..?

Answer 1

It appears that CTFontCopyPostScriptName() will always return a valid result for any string that is understood by [NSFont fontWithName:] - and vice versa.

At least in my experiments across 10.8 - 10.10 and using valid and made-up font names the results of CTFontCopyPostScriptName() could always be used to verify a font name will be valid for NSFont .

Edit #1
Some experimentation shows that it's a good idea to also add a fallback with CTFontCopyFamilyName() to be on the safe side.