부호를 붙이다

//    ,            
+ (UIImageView *)addWatermark
{
    static UIImageView * imageView = nil;
    if (imageView) {
        [imageView removeFromSuperview];
        return imageView;
    }

    NSString *str = @"wangyebin";
    if ([str isEqualToString:@""]) {
        return nil;
    }

    CGSize size = [UIScreen mainScreen].bounds.size;
    UIGraphicsBeginImageContext(size);

    [str drawInRect:CGRectMake(10, 20, size.width, 50) withAttributes:@{NSFontAttributeName:[UIFont fontWithName:@"Marker Felt" size:30],NSForegroundColorAttributeName:[UIColor colorWithRed:1 green:1 blue:1 alpha:1]}];
    [str drawInRect:CGRectMake(10, size.height/2, size.width, 50) withAttributes:@{NSFontAttributeName:[UIFont fontWithName:@"Marker Felt" size:30],NSForegroundColorAttributeName:[UIColor colorWithRed:0 green:0 blue:0 alpha:0.8]}];
    [str drawInRect:CGRectMake(10, size.height-50, size.width, 50) withAttributes:@{NSFontAttributeName:[UIFont fontWithName:@"Marker Felt" size:30],NSForegroundColorAttributeName:[UIColor colorWithRed:1 green:1 blue:0 alpha:0.8]}];

    //        
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    imageView = [[UIImageView alloc]initWithFrame:[UIScreen mainScreen].bounds];
    imageView.image = newImage;
    imageView.alpha = 0.005;

    return imageView;
}