How can draw a antialiasing line in 64 color watch?

I have impelmented an analog watch face as the following:

  you can see the line is not smooth in some angles. I know that it can be made to look a bit smoother by antialiasing tech in computer. But How Can I get it done in 64 color suppored device such as my Fenix X 5 plus?  I mentioned that because I found some of the default system providing analog watch faces look perfect.