wrapper.m

//
//  DOXLabelWrapper.m
//  Autolayout
//
//  Created by BJ Homer on 7/11/14.
//  Copyright (c) 2014 BJ Homer. All rights reserved.
//

#import "DOXLabelWrapper.h"

@interface DOXLabelWrapper()
@property (nonatomic) NSColor *color;
@property (nonatomic) CGFloat cornerRadius;
@property (nonatomic) NSTextField *titleField;
@end


@implementation DOXLabelWrapper


// In my test case, frame.size = {width: 163, height: 40}
- (instancetype)initWithFrame:(NSRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.color = [NSColor blueColor];
        self.cornerRadius = 8;
        
        CGRect textRect = CGRectInset(self.bounds, self.cornerRadius, self.cornerRadius);
        NSTextField *titleField = [[NSTextField alloc] initWithFrame:textRect];

        titleField.drawsBackground = false;
        titleField.editable = false;
        titleField.bezeled = false;
        titleField.bordered = false;
        titleField.stringValue = @"This is a string";
        titleField.textColor = [NSColor whiteColor];
        self.titleField = titleField;
        

        /// Setting this flag to YES causes the view to have no visible size.
        BOOL useAutoresizingMask = NO;
        
        if (useAutoresizingMask) {
            titleField.translatesAutoresizingMaskIntoConstraints = YES;
            titleField.autoresizingMask = (NSViewWidthSizable | NSViewHeightSizable);
            [self addSubview:titleField];
        }
        else {
            [self addSubview:titleField];
            titleField.translatesAutoresizingMaskIntoConstraints = NO;
            NSDictionary *views = NSDictionaryOfVariableBindings(titleField);
            [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|-(8)-[titleField]-(8)-|"
                                                                         options:0 metrics:0 views:views]];
            [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(8)-[titleField]-(8)-|"
                                                                         options:0 metrics:0 views:views]];
        }
        
        

        self.wantsLayer = YES;
    }
    return self;
}

- (BOOL)wantsUpdateLayer
{
    return YES;
}

- (void)updateLayer
{
    self.layer.backgroundColor = self.color.CGColor;
    self.layer.cornerRadius = self.cornerRadius;
}


@end

If useAutoresizingMask is YES, then the titleField shrinks down to height == 0, width == 4. This happens even though the titleField's -fittingSize is much larger than that.

Shouldn't the two code paths be equivalent?