delphi indy10

Question

我使用和xe4组件，并希望从Tidudpclient向Tidudpserver发送图像。我已经用tcp组件完成了这个操作，但是相同的代码并不适用于udp。我怎么能这么做？提前感谢！

Timage(客户端)-Timage(服务器)

客户端发送图像

var
    pic: tbitmap;
       Strm : TMemoryStream;
        img2:Timage;

    buffer:TIdBytes;
    begin

        try
          img2:=Timage.Create(nil);
          pic:=Tbitmap.Create;
          Takekpic(pic);     
          BMPtoJPG(pic,img2);
          Strm := TMemoryStream.Create;
          img2.Picture.bitmap.SaveToStream(strm);
          Strm.Position:=0;
          ReadTIdBytesFromStream(Strm,buffer,SizeOf(Strm),0);
          IdTrivialFTPServer1.SendBuffer('192.168.17.128',1234,buffer);
        finally
             strm.Free;
          end; 
    end;

服务器读取图像

procedure TForm6.IdTrivialFTP1UDPRead(AThread: TIdUDPListenerThread;
  const AData: TIdBytes; ABinding: TIdSocketHandle);
    var
Strm : TMemoryStream;
Jpg: TJpegImage;

begin
      Strm := TMemoryStream.Create;
      try    

         WriteTIdBytesToStream(Strm,AData,SizeOf(AData),0);
         strm.Position:=0;
         Jpg := TJpegImage.Create;
         jpg.LoadFromStream(Strm);  <---- error while reading (JPEG Error #53)
         img1.Picture.assign(jpg);
      finally
         strm.Free;
         Jpg.Free;
      end;
end;

这段代码有什么问题吗？

Answer 1

TIdUDPClient和TIdUDPServer不支持发送/接收TStream数据。您可以将图像数据保存到TStream中，但必须使用TIdBytes块发送/接收图像数据。

或者，使用TIdTrivialFTP和TIdTrivialFTPServer，它们实现基于UDP的文件传输协议TFTP .它们使用TStream对象进行操作。

更新：例如：

客户端：

var
  bmp: TBitmap;
  jpg: TJPEGImage;
  Strm : TMemoryStream;
begin
  Strm := TMemoryStream.Create;
  try
    jpg := TJPEGImage.Create;
    try
      bmp := TBitmap.Create;
      try 
        Takekpic(bmp);     
        jpg.Assign(bmp);
      finally
        bmp.Free;
      end;
      jpg.SaveToStream(Strm);
    finally
      jpg.Free;
    end;
    Strm.Position := 0;
    {
    These can be assigned ahead of time...
    IdTrivialFTP1.Host := '192.168.17.128';
    IdTrivialFTP1.Port := 1234;
    }
    IdTrivialFTP1.Put(Strm, 'image.jpg');
  finally
    Strm.Free;
  end; 
end;

服务器：

procedure TForm6.IdTrivialFTPServer1WriteFile(Sender: TObject; var FileName: String; const PeerInfo: TPeerInfo; var GrantAccess: Boolean; var AStream: TStream; var FreeStreamOnComplete: Boolean) of object;
begin
  if FileName = 'image.jpg' then
  begin
    GrantAccess := True;
    AStream := TMemoryStream.Create;
    FreeStreamOnComplete := True;
  end else
    GrantAccess := False;
end;

{
If you set TIdTrivialFTPServer.ThreadedEvent to False, this event handler
runs in the context of the main thread, so the UI can be accessed safely.
If you set IdTrivialFTPServer.ThreadedEvent to True, this event handler
runs in the context of a worker thread, so you will have to manually
synchronize with the main thread when updating the UI...
}
procedure TForm6.IdTrivialFTPServer1TransferComplete(Sender: TObject; const Success: Boolean; const PeerInfo: TPeerInfo; var AStream: TStream; const WriteOperation: Boolean);
var
  jpg: TJPEGImage;
begin
  if WriteOperation and Success then
  begin
    jpg := TJPEGImage.Create;
    try
      AStream.Position := 0;
      jpg.LoadFromStream(AStream);
      img1.Picture.Assign(jpg);
    finally
      jpg.Free;
    end;
  end;
end;