procedure TForm1.Rotate1Click(Sender: TObject);
{ Rotate selected objects. }
var
  i: Integer;
  ihObj: Integer;
  iRotateAngle: Integer;
begin
  with ImageEnVect1 do
  begin
    for i := 0 to SelObjectsCount - 1 do
    begin
      if i >= 0 then
      begin
        ObjSaveUndo;
        ihObj := SelObjects[i];
        if ihObj <> -1 then
        begin
          iRotateAngle := 90;
          RotateObject(ihObj, iRotateAngle, ierObject);
        end;
      end;
    end;
    Update;
  end;
end;