NSLog(@"點擊了");
    
    // 截屏
    // 開啟上下文
    UIGraphicsBeginImageContextWithOptions(self.imageView.frame.size, NO, 1);

    // 獲取上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    
    // 渲染圖層
    [self.imageView.layer renderInContext:ctx];
    
    // 獲取上下文中的圖片
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    //將UIImage轉換成CGImageRef
    CGImageRef sourceImageRef = [image CGImage];
    
    //按照給定的矩形區(qū)域進行剪裁
    CGImageRef newImageRef = CGImageCreateWithImageInRect(sourceImageRef, self.imageView.imageRectInView);
    
    //將CGImageRef轉換成UIImagenewImageRef
    UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
    
    // 關閉上下文
    UIGraphicsEndImageContext();