SUMMARY STEPS TO REPRODUCE 1. Download this file https://cgit.kde.org/khotkeys.git/tree/app/khotkeys.desktop 2. Open it in Kate 3. Try to edit and navigate through the file OBSERVED RESULT The editor is lagging. CPU usage is high. EXPECTED RESULT The editor should run smoothly. SOFTWARE/OS VERSIONS Operating System: openSUSE Tumbleweed 20200508 KDE Plasma Version: 5.18.5 KDE Frameworks Version: 5.69.0 Qt Version: 5.14.1 Kernel Version: 5.6.11-1-default OS Type: 64-bit Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz Memory: 31.1 GiB ADDITIONAL INFORMATION
I think QFontEngine only caches a certain amount of glyphs. If you are rendering in multiple writing systems, the cache is invalidated effectively for each line.
Guo I've just tested this in kate from git master. I cannot reproduce lag or any unusually high CPU usage. Can you please retest and confirm if this is still an issue for you?
I can still reproduce it with Kate 20.08.2. It may require some fonts to be installed.
(In reply to Guo Yunhe from comment #3) > I can still reproduce it with Kate 20.08.2. > > It may require some fonts to be installed. Are you able to try and boot KDE Neon User Edition in a Virtual Machine or on your PC (live USB is fine) and see if it's OK there.
I am in a hospital and the wifi doesn't allow me to download large files... These special languages fallback to GNU Unifont because it is the only font that cover these characters. I found that if you change the editor's font to GNU Unifont, then no matter what file you open, the editor is super slow when scrolling and editing. Also I am using 150% scaling in X11. It may affect.
Hi Guo, I hope you are fine. Feel free to test any time later. GNU Unifont is a bitmap font, which might indeed be slower to render, because the caches are optimized for scalable fonts. Please try with the Noto family; they should have all scripts covered. To rule out scaling, temporarily disable it to confirm it doesn't cause the slowdown.
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This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!