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

Answer 1

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.

Answer 2

Try this one:

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

Answer 3

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 4

Here is a more complete example of how you can do this using boundingRectWithSize.

// get the text field
NSTextField* field = (NSTextField*)view;

// create the new font for the text field
NSFont* newFont = [NSFont fontWithName:@"Trebuchet MS" size:11.0];

// set the font on the text field
[field setFont:newFont];

// calculate the size the textfield needs to be in order to display the text properly
NSString* text      = field.stringValue;
NSInteger maxWidth  = field.frame.size.width;
NSInteger maxHeight = 20000;
CGSize constraint   = CGSizeMake(maxWidth, maxHeight);
NSDictionary* attrs = [NSDictionary dictionaryWithObjectsAndKeys:NSFontAttributeName,newFont, nil];
NSRect newBounds    = [text boundingRectWithSize:constraint
                                         options:NSLineBreakByWordWrapping | NSStringDrawingUsesLineFragmentOrigin
                                      attributes:attrs];

// set the size of the text field to the calculated size
field.frame = NSMakeRect(field.frame.origin.x, field.frame.origin.y, field.frame.size.width, newBounds.size.height);

Of course, for additional info, take a look at the Apple documentation:

• Options for the attributes dictionary
• boundingRectWithSize

Answer 5

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 6

If you search the documentation for NSString, you will find the "NSString Application Kit Additions Reference", which is pretty much analogous to the UIKit counterpart.

-[NSString sizeWithAttributes:]

is the method you are looking for.