iOS - How to detect whether a font is bold/black/heavy...?

Question

I want to detect the style(bold ,heavy, black) of a font. But I can just detect whether the font is bold.

BOOL isBold = (font.fontDescriptor.symbolicTraits & UIFontDescriptorTraitBold)!=0;

There is no black or heavy trait in UIFontDescriptorSymbolicTraits.

A way is to check the font name whether contains 'black' or 'heavy' string, but this seems unreliable.

There is UIFontWeightTrait, but it's just for UIFont systemFontOfSize: weight:

And I want to create my custom font with a style if there is available these style.

Thanks, I already know how to detect bold/italic style as I mentioned in question. — tomfriwel, May 15 '17 at 08:49
I know how to achieve this in swift, but for others you may write a swift version. — tomfriwel, May 15 '17 at 08:56

Yun CHEN · Accepted Answer · 2017-05-15T09:02:12.010

To check if it's Heavy or Black:

NSString *fontUsage = font.fontDescriptor.fontAttributes[@"NSCTFontUIUsageAttribute"];
if ([fontUsage isEqualToString:@"CTFontHeavyUsage"]) {
    NSLog(@"It's Heavy");
}
else if ([fontUsage isEqualToString:@"CTFontBlackUsage"]) {
    NSLog(@"It's Black");
}

The list of other usage options are very simple, just put usage in format "CTFont......Usage", the list I tested are:

//CTFontUltraLightUsage,CTFontThinUsage,CTFontLightUsage,CTFontMediumUsage,CTFontDemiUsage

And How to create a font with usage, like heavy:

UIFontDescriptor *fontDescriptor = [[UIFontDescriptor alloc] initWithFontAttributes:@{@"NSCTFontUIUsageAttribute":@"CTFontHeavyUsage"}];
UIFont *font = [UIFont fontWithDescriptor:fontDescriptor size:17];

Swift3 version for checking:

if let fontUsage = font.fontDescriptor.fontAttributes["NSCTFontUIUsageAttribute"] as? String {
    if fontUsage == "CTFontHeavyUsage" {
        print("It's Heavy")
    }
    else if fontUsage == "CTFontBlackUsage" {
        print("It's Black")
    }
}

I just want this, Is there a list of string like "CTFontBlackUsage"? I also want to detect other style. — tomfriwel, May 15 '17 at 08:14

Shabir jan · Answer 2 · 2017-05-15T09:05:17.950

Swift Version for detecting Heavy/Black style of font

let fontUsage = font.fontDescriptor.fontAttributes["NSCTFontUIUsageAttribute"] as! String
if fontUsage == "CTFontHeavyUsage"{
    print("It is heavy")
}
else if fontUsage == "CTFontBlackUsage"{
    print("it's black")
}

and to create font with attributes:

let fontDescriptor = UIFontDescriptor(fontAttributes: ["NSCTFontUIUsageAttribute" : "CTFontHeavyUsage"])
let font = UIFont(descriptor: fontDescriptor, size: 17)

score 0 · Answer 3 · answered May 15 '17 at 08:12

This gives you whether a font is bold or not:

var isBold = label.font.fontDescriptor.symbolicTraits.contains(.traitBold)

Here is some experiement: this gives you the correct answer even if the a bold font is set, or if you set the font's symbolicTraits manually to be bold:

iOS - How to detect whether a font is bold/black/heavy...?

3 Answers3

Linked