SUMMARY The Desktop Bar does not respect the Global scale value set per monitor (kcm.globalScale). This is more evident on hidpi (4k) screens, where Global scaling is more often employed to enlarge UI elements. This is not an issue at 100% scale (most 1080p and 1440p displays). STEPS TO REPRODUCE 1. Set your resolution as high as it goes using Kscreen KCM. 2. Turn Global scaling up (200% or so) in the same KCM. 3. Log out and back in. OBSERVED RESULT Everything has enlarged except for the Desktop Bar (thumbnails are tiny) EXPECTED RESULT Desktop Bar should scale proportionally with the rest of the desktop elements (panels, decorations, etc) ADDITIONAL INFORMATION I proposed an enhancement to increase the default width of the Desktop Bar which uncovered this bug (https://invent.kde.org/plasma/kwin/-/merge_requests/6875). It was not intended as a solution to a scaling issue, but to offer functional ease of access to the bar at native scale. Evaluating the global scale would complement this solution, but one is not dependent on the other.
I took a close look at the Plasma codebase (i.e. many varied searches across kde-builder's tree), but could not find any instances where a previous desktop element was corrected and made to follow global scale. It's very clear where Kscreen and Kded get and set the global scale variable (converting to percentage and back), but I cannot find that resulting variable (kcm.globalScale) referenced anywhere else. Bit of a head scratcher so far!
>2. Turn Global scaling up (200% or so) in the same KCM. That means it's X11. Can you confirm if on Wayland it works as expected. >but I cannot find that resulting variable (kcm.globalScale) referenced anywhere els Somewhere on startup it gets into the environment variable QT_SCREEN_SCALE_FACTORS then Qt is using it implicitly everywhere to automatically scale.... everywhere except Kwin that is.
(In reply to David Edmundson from comment #2) > >2. Turn Global scaling up (200% or so) in the same KCM. > > That means it's X11. Can you confirm if on Wayland it works as expected. > Good catch on the distinction here, I had forgotten scale is handled differently in Wayland. Sure enough it scales properly in Wayland, here are screenshots showing both compositors at 1440p 200%. > >but I cannot find that resulting variable (kcm.globalScale) referenced anywhere else > > Somewhere on startup it gets into the environment variable > QT_SCREEN_SCALE_FACTORS then Qt is using it implicitly everywhere to > automatically scale.... everywhere except Kwin that is. Thanks for the pointer, I see `KCMKScreen::exportGlobalScale()` in kcm.cpp now. main_x11.cpp and startplasma-x11.cpp also transform this env variable before it is accessed. Could this mean that the effect is not using Qt units somewhere in the Overview/Bar QML definition? The base height is calculated using `Kirigami.Units.gridUnit`, but there are some other parameters in use, like KWinComponents.SceneView.screen.geometry.width
Created attachment 176462 [details] 1440p at 200% - X11 (Incorrect)
Created attachment 176463 [details] 1440p at 200% - Wayland (Correct)
Adding the x11-only keyword