Painting UIBarButton Image

PaintingBarButton.m

- (UIImage *)backButtonImage
{
    static UIImage *image;
    
    static dispatch_once_t predicate;
    dispatch_once(&predicate, ^{
        CGSize size = CGSizeMake(50.0, 44.0);
        UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
        
        [[UIColor whiteColor] setStroke];
        [[UIColor whiteColor] setFill];
        
        UIBezierPath *path = [UIBezierPath bezierPath];
        path.lineWidth = 1.5;
        path.lineCapStyle = kCGLineCapButt;
        path.lineJoinStyle = kCGLineJoinMiter;
        [path moveToPoint:CGPointMake(11.0, 11.0)];
        [path addLineToPoint:CGPointMake(1.0, 21.0)];
        [path addLineToPoint:CGPointMake(11.0, 31.0)];
        [path stroke];
        
        image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    });
    
    return image;
}

- (UIImage *)forwardButtonImage
{
    static UIImage *image;
    
    static dispatch_once_t predicate;
    dispatch_once(&predicate, ^{
        UIImage *backButtonImage = [self backButtonImage];
        
        CGSize size = backButtonImage.size;
        UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
        
        CGContextRef context = UIGraphicsGetCurrentContext();
        
        CGFloat x_mid = size.width / 2.0;
        CGFloat y_mid = size.height / 2.0;
        
        CGContextTranslateCTM(context, x_mid, y_mid);
        CGContextRotateCTM(context, M_PI);
        
        [backButtonImage drawAtPoint:CGPointMake(-x_mid, -y_mid)];
        
        image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    });
    
    return image;
}