A quartus.desktop file for launching Altera Quartus from desktop menus. I thought it might be useful to someone else.

quartus.desktop

[Desktop Entry]
Version=1.0
Name=Quartus II
Comment=Altera Quartus II Web Edition
GenericName=FPGA Tools
Keywords=FPGA;Programming;Development
Exec=/opt/altera/12.1/quartus/bin/quartus
Terminal=false
X-MultipleArgs=false
Type=Application
Icon=/opt/altera/12.1/quartus/adm/quartusii.png
Categories=Development;
MimeType=
StartupNotify=true
Actions=NewWindow;