1.普通界面

    /** 
     *截图功能 
     */  
    -(void)screenShot{  
        UIGraphicsBeginImageContextWithOptions(CGSizeMake(640, 960), YES, 0);  
      
        //设置截屏大小  
      
        [[self.view layer] renderInContext:UIGraphicsGetCurrentContext()];  
      
        UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();  
      
        UIGraphicsEndImageContext();  
      
        CGImageRef imageRef = viewImage.CGImage;  
        CGRect rect = CGRectMake(0, 0, 641, SCREEN_HEIGHT + 300);//这里可以设置想要截图的区域  
      
        CGImageRef imageRefRect =CGImageCreateWithImageInRect(imageRef, rect);  
        UIImage *sendImage = [[UIImage alloc] initWithCGImage:imageRefRect];  
       
      
        //以下为图片保存代码  
      
        UIImageWriteToSavedPhotosAlbum(sendImage, nil, nil, nil);//保存图片到照片库  
      
        NSData *imageViewData = UIImagePNGRepresentation(sendImage);  
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
      
        NSString *documentsDirectory = [paths objectAtIndex:0];  
        NSString *pictureName= @"screenShow.png";  
        NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:pictureName];  
        [imageViewData writeToFile:savedImagePath atomically:YES];//保存照片到沙盒目录  
      
        CGImageRelease(imageRefRect);      
      
      
      
        //从手机本地加载图片  
      
        UIImage *bgImage2 = [[UIImage alloc]initWithContentsOfFile:savedImagePath];  
      
          
    }  

2.UIScrollView截屏（一屏无法显示完整）

    /** 
     *截图 
     */  
    - (void)screenShot{  
        UIImage* image = nil;  
        UIGraphicsBeginImageContext(m_scrollView.contentSize);  
      
        {  
            CGPoint savedContentOffset = m_scrollView.contentOffset;  
            CGRect savedFrame = m_scrollView.frame;  
            m_scrollView.contentOffset = CGPointZero;  
      
            m_scrollView.frame = CGRectMake(0, 0, m_scrollView.contentSize.width, m_scrollView.contentSize.height);        [m_scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];  
      
            image = UIGraphicsGetImageFromCurrentImageContext();       
      
            m_scrollView.contentOffset = savedContentOffset;  
            m_scrollView.frame = savedFrame;  
        }  
        UIGraphicsEndImageContext();      
      
        if (image != nil) {  
            NSLog(@"截图成功!");  
      
        }  
    }