I use Kdenlive 17.12.2 on Arch Linux, my display scale is 1.2 under X11. Several icoins (from menus, toolbars and preferences window, for example) look pixelated.
Could you post some screenshots? If these are just the menus, I've noticed that as well in all applications, it is not specific to kdenlive.
Created attachment 111373 [details] screenshot
I confirm this issue on my system. I plan on working on this shortly.
I'm having MLT issues, this may be best for JB to fix. Most likely needs the following in main.cpp: QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
Git commit 42249e5007ba38ecf266d793685194ed3117deaf by Jean-Baptiste Mardelle. Committed on 27/03/2018 at 07:16. Pushed by mardelle into branch 'Applications/18.04'. Fix lowres icons on highdpi patch by Andrew Crouthamel M +1 -0 src/main.cpp https://commits.kde.org/kdenlive/42249e5007ba38ecf266d793685194ed3117deaf
Git commit 5cf26acf52242a3331317da5076675fa2da6c5b8 by Jean-Baptiste Mardelle. Committed on 27/03/2018 at 07:19. Pushed by mardelle into branch 'refactoring_timeline'. Fix lowres icons on highdpi patch by Andrew Crouthamel M +2 -1 src/main.cpp https://commits.kde.org/kdenlive/5cf26acf52242a3331317da5076675fa2da6c5b8