How to make subscripts and superscripts using NSAttributedString?

Question

I need to make subscripts for chemistry formulas (H2O, Na^2+, etc)?

Is this possible to do with NSAttributedString, or is there an alternative/easier way to make sub

Answer 1

For SubScript use value for kCTSuperscriptAttributeName as @-1.

As per the document

@discussion Value must be a CFNumberRef. Default is int value 0. If supported by the specified font, a value of 1 enables superscripting and a value of -1 enables subscripting.

extern const CFStringRef kCTSuperscriptAttributeName CT_AVAILABLE(10_5, 3_2);

 Example- [lblHeader setText:@“Headers [Alpha1 – text”];

        NSMutableAttributedString *headerSubscript = [[NSMutableAttributedString alloc]initWithAttributedString: lblHeader.attributedText];

        [headerSubscript addAttribute:(NSString *)kCTSuperscriptAttributeName value:@-1 range:NSMakeRange(14,1)];      

        [lblHeader setAttributedText:headerSubscript];