UIKit's [NSString sizeWithFont:constrainedToSize:] in AppKit

Question

Is there any equivalent method in AppKit (for Cocoa on Mac OS X) that does the same thing as UIKit's [NSString sizeWithFont:constrainedToSize:]?

If not, how could I go about getting the amount of space needed to render a particular string constrained to a width/height?

Update: Below is a snippet of code I'm using that I expect would produce the results I'm after.

NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:
                            [NSFont systemFontOfSize: [NSFont smallSystemFontSize]], NSFontAttributeName,
                            [NSParagraphStyle defaultParagraphStyle], NSParagraphStyleAttributeName,
                            nil];
NSSize size = NSMakeSize(200.0, MAXFLOAT);
NSRect bounds;

bounds = [@"This is a really really really really really really really long string that won't fit on one line"
             boundingRectWithSize: size
             options: NSStringDrawingUsesFontLeading
             attributes: attributes];

NSLog(@"height: %02f, width: %02f", bounds.size.height, bounds.size.width);

I would expect that the output width would be 200 and the height would be something greater than the height of a single line, however it produces:

height: 14.000000, width: 466.619141

Thanks!

Answer 1

Try this one:

bounds = [value boundingRectWithSize:size options:NSLineBreakByWordWrapping | NSStringDrawingUsesLineFragmentOrigin attributes:attributes];

Answer 2

The newer NSExtendedStringDrawing category API (methods with the NSStringDrawingOptions argument) behaves in the single line mode. If you want to measure/render in multi line mode, want to specify NSStringDrawingUsesLineFragmentOrigin.

Answer 3

EDIT: You should be able to do things the normal way in Lion and later. The problems described below have been fixed.

---

There is no way to accurately measure text among the current Mac OS X APIs.

There are several APIs that promise to work but don't. That's one of them; Core Text's function for this purpose is another. Some methods return results that are close but wrong; some return results that seem to mean nothing at all. I haven't filed any bugs on these yet, but when I do, I'll edit the Radar numbers into this answer. You should file a bug as well, and include your code in a small sample project.

[Apparently I have already filed the Core Text one: 8666756. It's closed as a duplicate of an unspecified other bug. For Cocoa, I filed 9022238 about the method Dave suggested, and will file two NSLayoutManager bugs tomorrow.]

This is the closest solution I've found.

Answer 4

If you want to constrain the string to a certain size, you use -[NSString boundingRectWithSize:options:attributes:]. The .size of the returned NSRect is the size you're looking for.