我怎么能从数据库中旋转图像

Question

我想旋转存储在数据库内的图像是可能的吗？ 我可以从数据库中获取图像，我只是不知道如何旋转它。

string img = (Request.QueryString["cn"]); 
    Byte[] bytes = null; 

    if (rbPhoto1.Checked == true) 
    { 
     if (img != null) 
     { 
      //string str = "select mem_contenttype, mem_photo from tblCardRequestDetail2 where mem_cardno = '" + Request.QueryString["cn"] + "'"; 
      string str = "select mem_contenttype1, mem_photo1 from tblphotoupload where mem_cardno = '" + img + "'"; 
      SqlCommand cmd = new SqlCommand(str); cmd.Parameters.Add("@1", SqlDbType.VarChar).Value = img; 
      DataTable dt = GetData(cmd); 


      bytes = (Byte[])dt.Rows[0]["mem_photo1"]; 
      Response.OutputStream.Write(bytes, 0, bytes.Length); 
      Response.Buffer = true; 
      Response.Charset = ""; 
      Response.Cache.SetCacheability(HttpCacheability.NoCache); 
      Response.ContentType = dt.Rows[0]["mem_contenttype1"].ToString(); 
      Response.AddHeader("content-disposition", "attachment;filename=" + dt.Rows[0]["mem_photo1"].ToString()); 
      Response.BinaryWrite(bytes); 
      Response.Flush(); 
      //Response.End(); 
     } 
    } 

Answer 1

你可以试试下面的代码

var memStream = new MemoryStream(bytes); 

Image imgFromStream = Image.FromStream(memStream, true); 
imgFromStream.RotateFlip(RotateFlipType.Rotate90FlipNone); 
imgFromStream.Save(memStream,System.Drawing.Imaging.ImageFormat.Jpeg);//Change to whichever format you need 
bytes = imgFromStream.ToArray(); 

Answer 2

您可以使用一个辅助方法是这样的：

public static byte[] ReadRotateAndWriteBitmap(byte[] imageBytes) 
    { 
     ImageConverter converter = new ImageConverter(); 
     using (Image img = (Image)converter.ConvertFrom(imageBytes)) 
     { 
      if (img == null) 
       return null; 
      img.RotateFlip(RotateFlipType.Rotate90FlipNone); 
      return (byte[])converter.ConvertTo(img, typeof(byte[])); 
     } 
    }