https://bugs.kde.org/show_bug.cgi?id=465158
--- Comment #36 from Matthias Dahl <ua_bugz_...@binary-island.eu> --- With the limited man power KWin has and this being a rather nasty problem (and not a priority), I wouldn't hold my breath for this to get fixed any time soon, I am afraid. I spent a few weeks trying to fix it, deep diving in kwin internals but at the end, I came to the conclusion that there is (imho) no way to make it work with all the floating point numbers and rounding. You have damage events in logical coordinates that are just one pixel in height... after scaling both coordinates and size, they have to perfectly fit where the damage is in device coordinates or you will end up with graphical glitches. That is extremely hard, if not impossible, to do right all the time. I shared my findings and tried to suggest a possible solution I called "fuzzy repaint". Basically you add a few pixel in each direction to the damage event to account for possible floating point/rounding errors. Even a very basic PoC on my end, fixed all glitches and worked fine. It would have required my work and thought to make it safe and sound, but it was better than what we have now and did not require a full repaint or anything else expensive. Unfortunately I was ignored (which is absolutely fine!), so I called it a day and moved on to different shores... :-( It's a pity really. On the surface, with KDE and KWin, you get pretty much everything you wished for with their handling of Wayland/Xwayland, scaling and HiDPI, but it has also has to work properly which is where it falls short. -- You are receiving this mail because: You are watching all bug changes.
