IW3 Desktop: Window capture doesn't work on linux

[RudiRastelli]

Window capturing doesn't seem to work on linux.
IW3-Desktop only captures the whole screen on the selected monitor.
Doesn't matter if streamer or local viewer mode.

Regards
Rudi

[tjandrasg]

@RudiRastelli please answer following questions:

• Wayland or X11?
• MSS or PIL?
• Master branch or Dev branch?
• GUI or CLI? (provide screenshoot of the config if possible)
• What Distro (and it's version) you are using?
• What DE (and it's version) you are using?
• What window you want to capture?

[nagadomi]

It may be Wayland, so please use X11 (Xorg).
See https://askubuntu.com/a/961345

One unfortunate thing is that X11 support has been dropped in Ubuntu 25.10.
I do not know the details yet, but it seems that screen capture is possible on Wayland using GStreamer or PipeWire, so we will probably need to implement support for Wayland at some point.

[tjandrasg]

Also it is possible to implement window capture on wayland using PyWayland but the window manager API for wayland is more complex than X11: https://pywayland.readthedocs.io/en/latest/module/protocol/xdg_shell.html?highlight=geometry#xdgpositioner (I still don't know how to get WlSurface from a target window)

Edit: Some screen capture API like PipeWire has internal window selector that directly record the surface of the window (not affected by occlusion or minimized) so PyWayland my not be needed in that case 👀

[nagadomi]

Wayland breaks screen recording applications

The following may be outdated information.

A particularly amusing example is screen recording not working. By design, Wayland doesn't allow clients to see the contents of another client. This is something I mostly regard as "security theater" (I don't install malware), but it's fine to make that the default. Just add some protocol to allow it right? Well in almost 14 years, they never came up with such a thing. There are many, obvious valid reasons why a user may want to record their screen, but somehow Wayland developers never bothered to address it. Hilariously enough, they didn't even fix this. The Pipewire guy did. To be fair, there were some various implementations beforehand (all compositor-specific), but in the end the solution that won was using Pipewire. Of course on the Pipewire side, it doesn't even use Wayland code at all. It communicates with Dbus to an xdg-desktop-portal. There are compositor backends for this, but the standard interface for fixing this problem is Dbus not Wayland.
https://dudemanguy.github.io/blog/posts/2022-06-10-wayland-xorg/wayland-xorg.html

[RudiRastelli]

• X11
• MSS
• Dev branch
• gui
• Mint 22.2
• Cinnamon
• Window of the Mint's default Media Player

Screenshot of IW3-Desktop-Settings

[RudiRastelli]

Sry... i was wrong when saying it captures the whole screen.
Instead it captures the area of the window + a bit more. Check out this screenshot:

You see that purple border around the image?
That's my desktop background.

[tjandrasg]

Instead it captures the area of the window + a bit more.

It's because of "shadow" effect from your window manager (cinnamon) is also considered part of the window, there is maybe(?) a little bug from X atom code but for now the possible solution for you is:

• Disable shadow effect
• Use Crop Region (Top, Left, Right, Bottom)
• Maybe there is another solution I am missing(?)

[nagadomi]

yeah, this occurs because the actual visible window and the captured window size do not match for various reasons. It also varies depending on the application displaying the GUI.
For example, capturing iw3.desktop.gui itself captures the exact area without the title bar. However, capturing google-chrome or gnome-terminal adds margins.
You can manually fix it by using Crop Region option.

I do not know an easy and good way to fix it.

[RudiRastelli]

Thanks for your efforts. It's not that important to me right now. I just noticed it.
I usually play my vids in full screen on my (virtual) 2nd screen and IW3 Desktop captures it. That works great.

Regrads
Rudi

[nagadomi]

At this point, I will not address it, but fixes are welcome.

[RudiRastelli]

@nagadomi @tjandrasg
I don't think cropping isn't a useful workaround. In my second screenshot, you can see very clearly that it's not the window itself that is being captured, but only a rectangular area of the screen where the window is currently located. This includes all windows that are currently above the window to be captured. In the screenshot, it is the IW3 Desktop window.

[nagadomi]

It is probably using the window size before resizing, that is, the size before "Start" is pressed.
That is an issue only with the iw3 desktop window.
In my environment, it fits perfectly.