Created attachment 163740 [details] screenshot showing windows off by one pixel SUMMARY *** NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols. See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports *** STEPS TO REPRODUCE 1. Create a dual monitor setup with fractional scaling (e.g., see output of kscreen-doctor -o below). The two monitors should be placed horizontally 2. Set Window Placement to Minimal Overlapping 3. Open a bunch of windows on the monitor on the left (e.g. in my setup, I ran seq 1 5 | xargs -I{} bash -c "xclock -geometry 800x1000 &") kscreen-doctor -o: Output: 1 eDP-2 enabled connected priority 1 Panel Modes: 0:2560x1600@240*! 1:2560x1600@60 2:1600x1200@60 3:1280x1024@60 4:1024x768@60 5:2560x1600@60 6:1920x1200@60 7:1280x800@60 8:2560x1440@60 9:1920x1080@60 10:1600x900@60 11:1368x768@60 12:1280x720@60 Geometry: 1920,0 1707x1067 Scale: 1.5 Rotation: 1 Overscan: 0 Vrr: Automatic RgbRange: Automatic HDR: incapable Wide Color Gamut: incapable ICC profile: none Output: 2 HDMI-A-1 enabled connected priority 2 HDMI Modes: 0:1920x1080@60*! 1:1920x1080@72 2:1920x1080@60 3:1920x1080@50 4:1680x1050@60 5:1600x900@60 6:1280x1024@60 7:1440x900@60 8:1280x800@60 9:1280x720@60 10:1280x720@60 11:1280x720@50 12:1024x768@70 13:1024x768@60 14:800x600@72 15:800x600@60 16:800x600@56 17:720x576@50 18:720x480@60 19:640x480@73 20:640x480@60 Geometry: 0,0 1920x1080 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: unknown HDR: incapable Wide Color Gamut: incapable ICC profile: none OBSERVED RESULT 1. Notice that some windows have one pixel on the screen on the right 2. Toggle "Present Windows", and notice that the windows with one pixel on the other monitor show up on both desktops. EXPECTED RESULT 1. All windows should fully reside in the desktop opening them. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.90.0 KDE Frameworks Version: 5.246.0 Qt Version: 6.6.1 Kernel Version: 6.6.3-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 20 × 13th Gen Intel® Core™ i9-13900H Memory: 15.2 GiB of RAM Graphics Processor: Mesa Intel® Graphics Manufacturer: ASUSTeK COMPUTER INC. Product Name: ROG Zephyrus G16 GU603VV_GU603VV System Version: 1.0 ADDITIONAL INFORMATION This is exactly the same issue that commit 5502ce9 [1] was supposed to solve. But it still happens in setups with fractional scaling. The cause is probably mixing ints and qreals in the calculations. [1] https://invent.kde.org/plasma/kwin/-/commit/5502ce9a9c0420bc4e12c4e224b926020a2e1170
I am planning to work on this. Solution probably very similar to the solution in 477820
(In reply to fanzhuyifan from comment #1) > I am planning to work on this. Solution probably very similar to the > solution in 477820 https://invent.kde.org/plasma/kwin/-/merge_requests/4740
Git commit c441ce5cd1a691c245d0d65ae5d9df10c91d328a by Yifan Zhu. Committed on 04/12/2023 at 17:59. Pushed by davidedmundson into branch 'master'. Avoid accidental mixing of qreal and int The code for placeSmart uses ints to store coordinates and dimensions, but the various methods of QRectF return qreal types, which can be non-integers under fractional scaling, causing multiple issues. This commit explicitly converts the needed quantities to ints, avoiding the issues. Previously, the code relied on the assumption that y = area.y() + area.height(); implies !(y < area.y() + area.height()). This doesn't always hold when mixing qreals and ints, causing infinite loops under fractional scaling when attempting to open large windows, as reported in BUG 477820. This commit also extends the fix in 5502ce9 to fractional scaling scenarios. The ceiling of client widths and height is used, instead of the implicit floor, which caused BUG 477886. Related: bug 477820 M +12 -7 src/placement.cpp https://invent.kde.org/plasma/kwin/-/commit/c441ce5cd1a691c245d0d65ae5d9df10c91d328a