流，VARIANT，图象间转换

          procedure   StreamToVariant(Stream:   TMemoryStream;     
                                                              var   v:     OleVariant);     
          procedure   VariantToStream(const   v:   olevariant;     
                                                              Stream:   TMemoryStream);     
          procedure   JPEGToVariant(aJPEG   :   TJPEGImage;     
                                                            var   aVariant:OleVariant);     
          procedure   VariantToJPEG(aValue   :   OleVariant;     
                                                            var   aJPEG:TJPEGImage);  
 procedure   TForm1.VariantToStream   (const   v   :   olevariant;   Stream   :   TMemoryStream);     
  var     
      p   :   pointer;     
  begin     
      Stream.Position   :=   0;     
      Stream.Size   :=   VarArrayHighBound   (v,   1)   -   VarArrayLowBound   (v,   1)   +   1;     
      p   :=   VarArrayLock   (v);     
      Stream.Write   (p^,   Stream.Size);     
      VarArrayUnlock   (v);     
      Stream.Position   :=   0;     
  end;     
    
  procedure   TForm1.StreamToVariant   (Stream   :   TMemoryStream;   var   v   :   OleVariant);     
  var     
      p   :   pointer;     
  begin     
      v   :=   VarArrayCreate   ([0,   Stream.Size   -   1],   varByte);     
      p   :=   VarArrayLock   (v);     
      Stream.Position   :=   0;     
      Stream.Read   (p^,   Stream.Size);     
      VarArrayUnlock   (v);     
  end;     
    
  procedure   TForm1.JPEGToVariant(aJPEG   :   TJPEGImage;   var   aVariant:OleVariant);     
  var     
      Stream                 :   TMemoryStream;     
  begin     
          try     
              Stream   :=   TMemoryStream.Create;     
    
              aJPEG.Assign(Image1.Picture.Bitmap);     
              aJPEG.SaveToStream(Stream);     
    
              StreamToVariant(Stream,   aVariant);     
          finally     
                Stream.Free;     
        end;     
  end;     
    
    
  procedure   TForm1.VariantToJPEG(aValue   :   OleVariant;var   aJPEG:TJPEGImage);     
  var     
        Stream   :   TMemoryStream;     
  begin     
  try     
      Stream   :=   TMemoryStream.Create;     
    
      VariantToStream   (aValue,Stream);     
      aJPEG.LoadfromStream(Stream);     
    
  finally     
        VariantClear(aValue);     
        Stream.free;     
  end;     
  end;     
    
  procedure   TForm1.Button2Click(Sender:   TObject);     
  var     
        aJPEG   :TJPEGImage;     
        aVariant   :   OleVariant;     
  begin     
  try     
        aJPEG:=TJPEGImage.Create;     
    
        //JPEG   To   Variant     
        aJPEG.Assign(Image1.Picture.Bitmap);     
        JPEGToVariant(aJPEG,aVariant);     
    
    
        //Variant   To   JPEG     
        VariantToJPEG(aVariant,aJPEG);     
        Image2.Picture.assign(aJPEG);     
  finally     
        aJPEG.free;     
  end;     
  end;