NSTextAlignment inverse of .Natural

I do no think that there is a text alignment "unnatural".

But you can retrieve the natural language direction from NSLocale with +characterDirectionForLanguage:. Having this, you can set set the alignment yourself.

NSLocale *locale = [NSLocale currentLocale];
UInt dir = [NSLocale characterDirectionForLanguage:locale.localeIdentifier];
NSLog(@"%d", dir); // returns 1 for left-to-right on my computer (German, de_DE) Hey, that should be ksh_DE!

In Apple's Internationalization and Localization Guide, under Supporting Right-to-Left Languages, they indicate that getting the layout direction should be done using UIView's semanticContentAttribute. So you could implement something like the following:

extension UIView {
    var isRightToLeftLayout: Bool {
        return UIView.userInterfaceLayoutDirection(for: self.semanticContentAttribute) == .rightToLeft
    }
}

This has the advantage of not relying on things like UIApplication, which depending on whether you're working in an extension or not (eg the Today widget), you might not have access to.

Thanks you @Oliver, here is what I ended up using in swift:

Extension

extension NSTextAlignment {
    static var invNatural: NSTextAlignment {
        return UIApplication.shared.userInterfaceLayoutDirection == .rightToLeft ? .left : .right
    }
}

Usage

myLabel.textAlignment = .invNatural

Heaven knows why Apple don't offer a NSTextAlignmentNaturalInverse or equivalent.

Here is the code we use to achieve this in our producation app...

+ (BOOL)isLanguageLayoutDirectionRightToLeft
{
    return [UIApplication sharedApplication].userInterfaceLayoutDirection == UIUserInterfaceLayoutDirectionRightToLeft;
}

someLabel.textAlignment = [UIApplication isLanguageLayoutDirectionRightToLeft] ? NSTextAlignmentLeft : NSTextAlignmentRight;