How to calculate NSMutableAttributedString height correctly?

Question

I have tried two methods:

attrString is NSMutableAttributedString

1.

CGRect rect = [attrString boundingRectWithSize:CGSizeMake(contentWidth, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading context:nil];

NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attrString];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeMake(contentWidth, CGFLOAT_MAX)];
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
[layoutManager addTextContainer:textContainer];
[textStorage addLayoutManager:layoutManager];
[layoutManager glyphRangeForTextContainer:textContainer];
CGRect rect = [layoutManager usedRectForTextContainer:textContainer];

But neither are right height.

Here is the demo: AttrStringDemo

Answer 1

I plus 1 to height after calculated the rect, it works.