For me the symptoms were first observed with PC-BSD 11.0-CURRENT. The first of my 2016 screenshots (below) is similar to the 2012 shot in Debian-related Fonts of some applications get confused so, reading the two questions alongside each other: it seems that the problem/symptoms may affect multiple desktop environments in both Linux and FreeBSD. From my screenshots: please, can anyone guess what's wrong? Hint: to clearly view the symptoms, you may find it necessary to view each shot full-size. In my case it's certain that symptoms are present for multiple users and multiple desktop environments  and most (maybe all) packages have been reinstalled. So: I guess that the problem is with a configuration file that is shared (not in any home directory). I tested a new user account, the problem persisted. ScreenshotsDocument Viewer (Evince)Poorly rendered fonts in the toolbar and sidebar of the application: XtermPoorly rendered font within the terminal window: Luxi Sans medium and Terminal in xfontselThe poorly rendered font sample in the lowest part of the application window (although from commentary below, and from glancing at xfontsel on a different computer, it may be that the pixellation is to be expected in this application): XfburnComparisonsThe shot of Xfburn may be most telling; the degraded appearance is not limited to fonts. Compare what's above with a 2010 shot (from Xfburn  A tool the size of the task | Written and Read): When I choose a PC-BSD 10.2-RELEASE boot environment on the affected machine, there's no problem. In this shot from 10.2, (GNOME) SystemMonitor appears fine: Additional notesWhen I logged in to MATE, the fonts in its menu bar were pixellated. Without running X, I ran the following command to force reinstallation (or upgrade) of all packagespkg upgrade -f then restarted the operating system. That pkg routine did not work around the problem. As far as I can tell, the poor font rendering is no better when VESA mode applies. Shortlist of some affected applicationsFiles (nautilus) 3.18.5Gnote 3.18.1HexChat 2.10.2Pidgin 2.10.12 (libpurple 2.10.12)System Monitor (gnome-system-monitor) 3.16.0Web (epiphany) 3.16.3Xfburn 0.5.4XTerm 322Shortlist of some non-affected applicationsAt a glance: Firefox 44.0.2Konsole 2.14.2Konversation 1.5.1KSnapshot 0.8.2System Log (KSystemLog) 0.4Thunderbird 38.6.0GTKNeither /usr/local/etc/gtk-2.0/gtkrc nor /usr/local/etc/gtk-3.0/settings.ini exists$ cat /usr/local/etc/gtk-2.0/gtkrccat: /usr/local/etc/gtk-2.0/gtkrc: No such file or directory$ ls -al /usr/local/etc/gtk-2.0/total 9drwxr-xr-x   2 root  wheel    3  8 Feb 20:26 .drwxr-xr-x  67 root  wheel  154 21 Feb 22:25 ..-rw-r--r--   1 root  wheel  890  5 Feb 13:52 im-multipress.conf$ cat /usr/local/etc/gtk-3.0/settings.inicat: /usr/local/etc/gtk-3.0/settings.ini: No such file or directory$ ls -al /usr/local/etc/gtk-3.0/total 9drwxr-xr-x   2 root  wheel    3 21 Feb 22:16 .drwxr-xr-x  67 root  wheel  154 21 Feb 22:25 ..-rw-r--r--   1 root  wheel  890 16 Feb 22:08 im-multipress.conf$  from a separate installation of PC-BSD 11.0-CURRENTJAN2016 it seems, that's the norm. From discussion in irc://chat.freenode.net/#pcbsd it's assumed that their nonexistence implies default values. Selected comments from beyond Stack ExchangeFrom a developer: Sorry Graham, I don't really have an idea of what could be causing this. Looks like gtk is going nuts on your system, or some lower-level X issues.Good luck  BackgroundAs far as I recall, the problem in my case arose from intentionally aggressive testing of PC-BSD 11.0-CURRENTFEB2016 with portmaster(8). During a run of portmaster, probably sudo portmaster -GaD I launched a type of application that might cause the hardware (Ergo Vista 621 notebook with Intel GM45 graphics) to blackout with anything more recent than 11.0-CURRENTNOV2015. Sure enough, a blackout occurred with no response to Control-Alt-F2 and so I pressed the power button to shut down the system as gracefully as possible in the midst of works by portmaster. I have ZFS boot environments for both 11.0-CURRENTNOV2015 and 11.0-CURRENTFEB2016. Since the problem occurred whilst testing the latter, the symptom is present in both environments. 
Degraded areas of some user interfaces, including pixellated or jagged fonts
linux;freebsd;configuration;fonts;gui