image.layer.cornerRadius = 8;
 image.layer.masksToBounds = YES;

//注意背景色要和cell的背景色設置一致哦，不然－0-
- (void)drawRect:(CGRect)rect {
    CGRect bounds = self.bounds;
    [[UIColor whiteColor]set];
    UIRectFill(bounds);
    [[UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:8.0] addClip];
    [self.image drawInRect:bounds];
}

- (void)setImage:(UIImage *)image {
    _image = image;
    //需要這一步，需要刷新，不然顯示會出問題
    [self setNeedsDisplay];
}

- (void)dealloc {
    self.image = nil;
}

- (UIImage *)imageByComposingImage:(UIImage *)image withMaskImage:(UIImage *)maskImage {
    CGImageRef maskImageRef = maskImage.CGImage;
    CGImageRef maskRef = CGImageMaskCreate(CGImageGetWidth(maskImageRef),
                                           CGImageGetHeight(maskImageRef),
                                           CGImageGetBitsPerComponent(maskImageRef),
                                           CGImageGetBitsPerPixel(maskImageRef),
                                           CGImageGetBytesPerRow(maskImageRef),
                                           CGImageGetDataPRovider(maskImageRef), NULL, false);
    
    CGImageRef newImageRef = CGImageCreateWithMask(image.CGImage, maskRef);
    CGImageRelease(maskRef);
    UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
    CGImageRelease(newImageRef);
    
    return newImage;
}