Get number of lines required for a UILabel

UILabel+GetLines.h

@interface UILabel (GetLines)

- (NSArray*) lines;

@end

UILabel+GetLines.m

#import "UILabel+GetLines.h"


@implementation UILabel (GetLines)

- (NSArray*) lines
{
    if ( self.lineBreakMode != UILineBreakModeWordWrap )
    {
        return nil;
    }
    
    NSMutableArray* lines = [NSMutableArray arrayWithCapacity:10];
    
    NSCharacterSet* wordSeparators = [NSCharacterSet whitespaceAndNewlineCharacterSet];
    
    NSString* currentLine = self.text;
    int textLength = [self.text length];
    
    NSRange rCurrentLine = NSMakeRange(0, textLength);
    NSRange rWhitespace = NSMakeRange(0,0);
    NSRange rRemainingText = NSMakeRange(0, textLength);
    BOOL done = NO;
    while ( !done )
    {
        // determine the next whitespace word separator position
        rWhitespace.location = rWhitespace.location + rWhitespace.length;
        rWhitespace.length = textLength - rWhitespace.location;
        rWhitespace = [self.text rangeOfCharacterFromSet: wordSeparators options: NSCaseInsensitiveSearch range: rWhitespace];
        if ( rWhitespace.location == NSNotFound )
        {
            rWhitespace.location = textLength;
            done = YES;
        }
        
        NSRange rTest = NSMakeRange(rRemainingText.location, rWhitespace.location-rRemainingText.location);
        
        NSString* textTest = [self.text substringWithRange: rTest];
        
        CGSize sizeTest = [textTest sizeWithFont: self.font forWidth: 1024.0 lineBreakMode: UILineBreakModeWordWrap];
        if ( sizeTest.width > self.bounds.size.width )
        {
            [lines addObject: [currentLine stringByTrimmingCharactersInSet:wordSeparators]];
            rRemainingText.location = rCurrentLine.location + rCurrentLine.length;
            rRemainingText.length = textLength-rRemainingText.location;
            continue;
        }
        
        rCurrentLine = rTest;
        currentLine = textTest;
    }
    
    [lines addObject: [currentLine stringByTrimmingCharactersInSet:wordSeparators]];
    
    return lines;
}

@end