NSButton checkbox with wrapping title (despite what IB says a check box title does not wrap)

BPCheckBoxButton.m

#import <Cocoa/Cocoa.h>

@interface BPCheckBoxButton : NSButton

@end

@implementation BPCheckBoxButton

- (void)setTitle:(NSString *)aString
{
    /*
     Check box title does not wrap by default, despite what IB says.
     */
    CGFloat imageWidth = self.image.size.width;
    // rough estimate. more exact metrics may be available.
    CGFloat maxWidth = self.frame.size.width - imageWidth * 1.5;
    aString = [aString bp_wrapStringMaxWidth:maxWidth forFont:self.font];
    
    [super setTitle:aString];
    
}

@end

NSString+CheckBox.m

@interface NSString (CheckBox)
- (NSArray *)bp_splitStringMaxWidth:(CGFloat)width font:(NSFont *)font;
- (NSString *)bp_wrapStringMaxWidth:(CGFloat)width forFont:(NSFont *)font;
@end

@implementation NSString (CheckBox)

- (NSArray *)bp_splitStringMaxWidth:(CGFloat)width font:(NSFont *)font
{
    
    NSMutableArray *tempArray = [NSMutableArray arrayWithCapacity:1];
    NSArray *wordArray = [self componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    NSString *line = @"";
    NSString *lineWithNext = @"";
    NSDictionary *attributes = [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
    
    for (NSUInteger i = 0; i < [wordArray count]; i++) {
        if (line.length == 0) { line = [wordArray objectAtIndex:i]; }
        
        if (i+1 < [wordArray count]) {
            lineWithNext = [[NSArray arrayWithObjects:line, [wordArray objectAtIndex:i+1], nil] componentsJoinedByString:@" "];
            if (((int)[lineWithNext sizeWithAttributes:attributes].width) <= width) {
                line = lineWithNext;
            } else {
                [tempArray addObject:line];
                line = @"";
            }
        } else {
            [tempArray addObject:line];
        }
    }
    return tempArray;
}

- (NSString *)bp_wrapStringMaxWidth:(CGFloat)width forFont:(NSFont *)font
{
    NSArray *components = [self bp_splitStringMaxWidth:width font:font];
    NSString *wrappedString = [components componentsJoinedByString:@"\n"];
 
    return wrappedString;
}

@end