图像在另一个图像内

Question

我基于这段代码：Custom MKAnnotationView with frame,icon and image

我试图做的有点不同......我的图像不透明，我想把图像放在里面。 我的问题是背景图像覆盖了我的图像。所以它看起来像：http://cl.ly/image/0E0S00072G1n

我的代码是这样的：

    annotationImageView.image = [UIImage imageNamed:@"marker_fb"];

    UIImage *frame = [UIImage imageNamed:@"marker_fb"];
    ImagePin *imagePinImage = annotation;   

    NSString *urlStringForImage = [NSString stringWithFormat:@"%@", imagePinImage.image];
    NSURL *urlForImage = [NSURL URLWithString:urlStringForImage];
    UIImageView *imageView = [[UIImageView alloc] init];

    [imageView setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@", urlForImage]] placeholderImage:[UIImage imageNamed:@"avatar-placeholder.png"]];

    UIGraphicsBeginImageContext(CGSizeMake(annotationImageView.image.size.width, annotationImageView.image.size.height));
    [frame drawInRect:CGRectMake(0, 0, frame.size.width, frame.size.height)];
    [imageView.image drawInRect:CGRectMake(2, 2, 48, 38)]; // the frame your inner image

    annotationImageView.image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

对象-c中是否存在z-indez？或者我该怎么办？ 谢谢。 编辑：我也尝试过：

UIGraphicsBeginImageContextWithOptions(CGSizeMake(annotationImageView.image.size.width, annotationImageView.image.size.height), NO, 0);