Borderless Fullscreen

[kiyote]

I'm just curious if there's a trick to a borderless fullscreen mode. FWIW - I'm on Linux (specifically CachyOS, KDE Plasma).

I've discovered the first trick that you cannot set the options.WindowBorder = WindowBorder.Hidden before the Load handler runs. So, I capture the created window and set that in my Load method and the border is removed, that's great.

But, if I set the options.WindowState = WindowState.Fullscreen then I get an exclusive fullscreen application. That is, when I task switch my program is minimzed, but I'd like to be able to switch and have applications on top.

I tried options.WindowState = WindowState.Maximized but that leaves the window with the taskbar on top.

I've tried setting the window.TopMost = true, to no effect.

The behaviour I'm looking for is (apparently) technically possible as if I start it up with something like:

			options.Size = new Vector2D<int>( screenResolution.X, screenResolution.Y );
			options.WindowState = WindowState.Normal;
			options.Position = mainMonitor.Bounds.Origin;

and then toggle the border off in the Load, I get the application filling the screen with the taskbar on top. I then can right-click the app in the taskbar, select More and toggle Fullscreen and now the application works like I'm hoping.

Has anyone successfully made a borderless fullscreen window on Linux?

[krotname]

I do not think there is a separate “borderless/windowed fullscreen” state exposed by Silk.NET 2.x right now.

From the current windowing API, WindowState only has Normal, Minimized, Maximized, and Fullscreen. On the GLFW backend, setting WindowState.Fullscreen goes through glfwSetWindowMonitor(...), and Silk.NET detects fullscreen by checking whether glfwGetWindowMonitor(...) is non-null. So that path is the monitor/fullscreen path, not the KDE window-manager “make this normal window fullscreen” toggle.

WindowBorder.Hidden is the other half of what you want: on GLFW it maps to Decorated = false. TopMost maps to GLFW Floating, so it is not a replacement for the WM fullscreen state either.

The portable Silk.NET workaround is basically the one you already found:

var monitor = Monitor.GetMainMonitor();

options.WindowState = WindowState.Normal;
options.WindowBorder = WindowBorder.Hidden;
options.Position = monitor.Bounds.Origin;
options.Size = monitor.Bounds.Size;

or set the border/position/size from Load if your version/backend does not apply the border hint early enough.

If you specifically need KDE's “Fullscreen” window action, that looks like a WM-level EWMH/KWin state rather than something Silk.NET's common windowing API currently exposes. So the choices are probably: use the borderless-normal-window workaround, add a platform-specific X11/KWin call after the native window is created, or open a feature request for a distinct WindowedFullscreen/FullscreenDesktop state. SDL has a FullscreenDesktop concept underneath, but Silk.NET's common WindowState.Fullscreen does not expose that distinction today.

[kiyote]

Thank you for the substantial response, I very much appreciate your insight. I'm looking at p/invoking something to do the fullscreen toggle action as a post-load operation as a workaround. I sort of figured that's where I'd end up, but I thought I'd double-check first.

I can only imagine the pain of trying to support so many different windowing standards. As they say - the great thing about standards is there are so many to choose from!