How to set LCD DPI

1.
On the Terminal, enter
sudo nano /etc/rc.local
Add the followwing code
-------------------------------------------
fi
startx -- -dpi 60 &
exit 0
id
---------------------------------------------
Change the "60" in "-- -dpi 60" to the bigger number like "120" ,
The display fonts will become bigger
Change the "60" in "-- -dpi 60" to the bigger number like "30" ,
The display fonts will become smaller

2.
On the Terminal, enter
sudo raspi-config
choose "Boot Options"->"Console Autologin"