NSAttributedString height calculation category

NSAttributedString+Height.m

@import CoreText;

@implementation NSAttributedString (Size)

- (CGFloat)heightForAttributedStringWithWidth:(CGFloat)inWidth {
    if (self.length == 0) {
        return 0;
    }

    NSTextStorage *textStorage = [[NSTextStorage alloc]
                                  initWithAttributedString:self];
    NSTextContainer *textContainer = [[NSTextContainer alloc]
                                       initWithSize: CGSizeMake(inWidth, FLT_MAX)];
    NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];

    [layoutManager addTextContainer:textContainer];
    [textStorage addLayoutManager:layoutManager];

    UIFont *font = [self attribute:NSFontAttributeName
                           atIndex:0
             longestEffectiveRange:nil
                           inRange:NSMakeRange(0, [textStorage length])];

    [textStorage
     addAttribute:NSFontAttributeName value:font
     range:NSMakeRange(0, [textStorage length])];

    [textContainer
     setLineFragmentPadding:0.0];

    layoutManager.usesFontLeading = false;

    [layoutManager
     ensureGlyphsForGlyphRange:NSMakeRange(0, [textStorage length])];

    (void) [layoutManager
            glyphRangeForTextContainer:textContainer];
  
    CGFloat height = [layoutManager
            usedRectForTextContainer:textContainer].size.height;

    return height;
}

@end