ImageEnView1.IEBitmap.Assign( bmp );
  ImageEnView1.IEBitmap.SynchronizeRGBA( true );
  ImageEnView1.Update();

MyBMP.SetTransparentColors( clBlack, clBlack, 0 );

procedure TplayAVI.ToolButton16Click(Sender: TObject);
var
    i,   j,   uG:   Integer;
    P:   PByteArray;
    bggray: integer;
    bmp:Tbitmap;
    layerno:integer;
begin
          ImageEnvect3.IEBitmap.Assign(imageenvect0.ieBitmap);
          imageenvect3.Update;

          IDSImageEnvect.Bitmap.Assign(imageenvect0.Bitmap);
          IDSimageenvect.Update;

          GrayToColor(IDSimageenvect.Bitmap);  //This procedure will turn the gray image into color image.
          IDSimageenvect.Proc.CopyToClipboard(iecpauto)  ;  //This will copy an ROI to the clipboard.

 //-------create bmp and get rid of the given pixels such as clblack pixels.
          bmp:=Tbitmap.Create;
          bmp.Assign(clipboard);
          bggray:= strtoint(backgroundgrayedit.Text) ;
          for   j   :=   0   to   Bmp.Height   -   1   do
          begin
                 P   :=   Bmp.ScanLine[j];
                for   i   :=   0   to   Bmp.Width   -   1   do
                begin
                      uG   :=   P[3   *   i];
                      if   ug< bggray then   //set the pixels to be clblack.
                      begin
                           P[3   *   i   +   2]   :=   0;
                           P[3   *   i   +   1]   :=   0;
                           P[3   *   i]   :=   0;
                     end;
                 end;
           end;
              Bmp.PixelFormat   :=   pf32bit;
              Bmp.TransparentColor:=clblack;   //set the black pixels in bmp to be transparent
              Bmp.Free;
  
              ImageEnVect3.Proc.PasteFromClipboard(iecpSelection);    //Paste the bmp file into the ROI in Imageenvect3.
              imageenvect3.Update;
end;

ImageEnView1.Proc.CopyToClipboard(iecpAuto);
idx := ImageEnView2.Proc.LayersCreateFromClipboard();
ImageEnView2.Layers[idx].Opacity := 10;
ImageEnView2.Update();