In this article, we will fix the display of fonts in Debian GNU/Linux Stretch.

su -c 'dpkg-reconfigure fontconfig-config'

answer Native, Automatic, Yes

touch .fonts.conf
nano .fonts.conf

Go to link:
https://pastebin.com/M1Q52g3D

create, or paste into .Xdefaults:

Xft.autohint: 0
Xft.antialias: 1
Xft.hinting: true
Xft.hintstyle: hintslight
Xft*dpi: 96
Xft.rgba: rgb
Xft.lcdfilter: lcddefault

And logout and login again.