function TformMain.IsMouseWithinImageBoundaries(const X, Y: Integer): Boolean;
begin
  Result := False;

  var bx := ImageEnView1.XScr2Bmp(X, False);
  var by := ImageEnView1.YScr2Bmp(Y, False);

  if (bx >= 0) and
     (bx < ImageEnView1.IEBitmap.Width) and
     (by >= 0) and
     (by < ImageEnView1.IEBitmap.Height)
  then Result := True;
end;