AddSpacesToCharacters.m

- (NSString *)addSpacesToCharacters:(NSArray *)characters {
    if (characters.count <= 1) {
        return characters.firstObject;
    }
    // bounding rect of base string, divide by length, calculate optimium number of spaces
    
    CGRect boundingRect = CGRectZero;
    CGSize constraintSize = self.view.frame.size;
    
    NSString *string = [characters componentsJoinedByString:@""];
    
    UIFont *drawingFont = self.myLabel.font;
    NSDictionary *attributes = @{NSFontAttributeName : drawingFont, NSForegroundColorAttributeName : [UIColor blackColor]};
    
    boundingRect = [string boundingRectWithSize:constraintSize options:NSStringDrawingUsesDeviceMetrics attributes:attributes context:nil];
    
    CGFloat width = boundingRect.size.width;
    CGFloat characterSize = width / string.length;
    CGFloat targetSize = self.view.frame.size.width - 20.f;
    
    CGFloat difference = targetSize - width;
    int spacesNeeded = ceilf(difference / characterSize);
    int numGaps = (int)string.length - 1;
    int spacesPerGap = spacesNeeded / numGaps;
    
    return [characters componentsJoinedByString:[@"" stringByPaddingToLength:spacesPerGap withString:@" " startingAtIndex:0]];
}