BMP与Variant类型的转换

procedure TForm2.VariantToBMP(aValue : OleVariant;var aBmp:TBitmap); 
var 
   Stream : TMemoryStream; 
begin 
try 
  Stream := TMemoryStream.Create; 

  VariantToStream (aValue,Stream); 
  aBmp.LoadfromStream(Stream); 

finally 
   VariantClear(aValue); 
   Stream.free; 
end; 
end; 

procedure TForm2.BMPToVariant(aBmp : TBitmap; var aVariant:OleVariant); 
var 
  Stream        : TMemoryStream; 
begin 
    try 
       Stream := TMemoryStream.Create; 

       Image1.Picture.Bitmap.SaveToStream(Stream); 

       StreamToVariant(Stream, aVariant); 
    finally 
       Stream.Free; 
   end; 
end; 

rocedure TForm2.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 TForm2.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;