iphone - How to get the font-size or a bold-version of UIFont instance

Question

How to get the font-size of a UIFont instance?

Or, if someone can implement this method for UIFont?

- (UIFont *)boldFont;

question from:https://stackoverflow.com/questions/6544132/how-to-get-the-font-size-or-a-bold-version-of-uifont-instance

Answer 1

UIFontDescriptor is pretty powerful class and can be used to get bold version of the font you want. It should be totally safe and future proof as it only requires usage of public API and doesn't depend on any string modifications.

Here is the code in Swift 3:

extension UIFont {

    func bold() -> UIFont? {
         let fontDescriptorSymbolicTraits: UIFontDescriptorSymbolicTraits = [fontDescriptor.symbolicTraits, .traitBold]
         let bondFontDescriptor = fontDescriptor.withSymbolicTraits(fontDescriptorSymbolicTraits)
         return bondFontDescriptor.flatMap { UIFont(descriptor: $0, size: pointSize) }
    }

}

Here is the code in objective-c:

@implementation UIFont (RABoldFont)

- (UIFont *)ra_boldFont
{
    UIFontDescriptor *fontDescriptor = [self fontDescriptor];
    UIFontDescriptorSymbolicTraits traits = fontDescriptor.symbolicTraits;
    traits = traits | UIFontDescriptorTraitBold;
    UIFontDescriptor *boldFontDescriptor = [fontDescriptor fontDescriptorWithSymbolicTraits:traits];
    return [UIFont fontWithDescriptor:boldFontDescriptor size:self.pointSize];
}

@end