cocoa - How to get height for NSAttributedString at a fixed width

Question

I want to do some drawing of NSAttributedStrings in fixed-width boxes, but am having trouble calculating the right height they'll take up when drawn. So far, I've tried:

1. Calling - (NSSize) size, but the results are useless (for this purpose), as they'll give whatever width the string desires.

2. Calling - (void)drawWithRect:(NSRect)rect options:(NSStringDrawingOptions)options with a rect shaped to the width I want and NSStringDrawingUsesLineFragmentOrigin in the options, exactly as I'm using in my drawing. The results are ... difficult to understand; certainly not what I'm looking for. (As is pointed out in a number of places, including this Cocoa-Dev thread).

3. Creating a temporary NSTextView and doing:
   [[tmpView textStorage] setAttributedString:aString];
[tmpView setHorizontallyResizable:NO];
[tmpView sizeToFit];
   When I query the frame of tmpView, the width is still as desired, and the height is often correct ... until I get to longer strings, when it's often half the size that's required. (There doesn't seem to be a max size being hit: one frame will be 273.0 high (about 300 too short), the other will be 478.0 (only 60-ish too short)).

I'd appreciate any pointers, if anyone else has managed this.

Answer 1

-[NSAttributedString boundingRectWithSize:options:]

You can specify NSStringDrawingUsesDeviceMetrics to get union of all glyph bounds.

Unlike -[NSAttributedString size], the returned NSRect represents the dimensions of the area that would change if the string is drawn.

As @Bryan comments, boundingRectWithSize:options: is deprecated (not recommended) in OS X 10.11 and later. This is because string styling is now dynamic depending on the context.

For OS X 10.11 and later, see Apple's Calculating Text Height developer documentation.