3. 本文摘自：
4. 本文参考：
5. UIGraphicsBeginImageContext(pictureView.bounds.size); 
                
7. [pictureView.layer renderInContext:UIGraphicsGetCurrentContext()]; 
9. UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
11. UIGraphicsEndImageContext();
13. UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);