UIKit [NSString sizeWithFont: constrainedToSize:] in AppKit

Question

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

If not, how can I get the amount of space needed to render a specific row limited by width / height?

Update: The following is a snippet of the code I'm using that I expect will produce the results I got 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 the width of the output file to be 200 and the height to be greater than the height of one line, however it produces:

 height: 14.000000, width: 466.619141 

Thanks!

Answer 1

EDIT: You should be able to do something in the usual way in Lion and later. The issues described below have been fixed.

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It is not possible to accurately measure text between the current Mac OS X APIs.

There are several APIs that promise to work, but do not work. This is one of them; The Core Text function for this purpose is different. Some methods return results that are close but incorrect; some return results that seem to mean nothing. I haven't submitted any errors to them yet, but when I do, I will edit the Radar numbers in this answer. You should also point out the error and include your code in a small sample project.

[Apparently, I have already submitted the main text: 8666756. It was closed as a duplicate of another unspecified error. For Cocoa, I filed 9022238 about the method proposed by Dave, and tomorrow will output two NSLayoutManager errors.]

This is the closest solution I have found.

Answer 2

Try the following:

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

Answer 3

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

Answer 4

If you want to limit the string to a specific size, you use -[NSString boundingRectWithSize:options:attributes:] . .size returned NSRect is the size you are looking for.

Answer 5

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, check out the Apple documentation for more information:

• Parameters for the Attribute Dictionary
• boundingRectWithSize

Answer 6

If you are looking for documentation for NSString , you will find the NSString Application Kit Add-ons Reference, which is pretty much the same as UIKit.

 -[NSString sizeWithAttributes:] 

is the method you are looking for.