On Mon Aug 11 08:02:59 2025 +0000, Zhiyi Zhang wrote:
It's also related to the exclusive fullscreen mode support, which we don't have. For example, when using exclusive fullscreen mode, the rendered content covers the exact fullscreen size, regardless of the window size. So using _NET_WM_STATE_FULLSCREEN is a workaround for that. Implementing exclusive fullscreen seems possible. For example, [0001-dxgi-tests-Test-moving-the-window-for-a-fullscreen-swa.txt](/uploads/9e65af02f7ed1fed7c194dd99024ea02/0001-dxgi-tests-Test-moving-the-window-for-a-fullscreen-swa.txt) [0002-dxgi-Implement-exclusive-screen-mode-for-d3d11.txt](/uploads/b9ebb8e5cfe5f78b175ab3b8618cbd38/0002-dxgi-Implement-exclusive-screen-mode-for-d3d11.txt).
FWIW even without multiple monitors a window can be larger than screen on Windows (and at least without fullscreen mode it is not getting resized or de-factor shrinked to the fullscreen size). Some games (one I remember offhand which was doing that at least back then is Halo Infinite) do that, make a window with decorations bigger than screen and position in a way so client area matches full screen size.
It is probably not possible to match all the aspects of Windows behaviour for all the cases in the x11 interfacing limitations? IMO if we de facto have a choice between taskbar appearing on top (that is maybe correctable by user clicking the window?) and ending up with wrong window sizes maybe it is better to sacrifice the taskbar but keep sizes correct? And think or ask if it is possible to do something in KDE to support, maybe some property indicating fullscreen request without altering the size?