Is it working with labwc ?

[ogmkp]

Hello,

I installed Screengrab 3.1.0 on Debian 13 stable in the LXQT 2.3.0 environment with LabWC 0.9.3, and I can't get it to work.

When I launch it, it goes to the tray icon, I open it from the icon, I click on + new and nothing happens, the software remains frozen, there is nothing written in the terminal.

What am I missing?

[tsujan]

Is it working with labwc ?

Yes, of course. I use it on a regular basis, under Labwc and Wayfire alike.

What am I missing?

No idea. I can't guess either based on the provided info.

[ogmkp]

Maybe this backtrace could help, but I don't know how to read it.

#0  0x00007ffff5ea59ee in ??? () at /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007ffff5e9a668 in ??? () at /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007ffff5e9a6ad in ??? () at /lib/x86_64-linux-gnu/libc.so.6
#3  0x00007ffff5f0ee6e in ppoll () at /lib/x86_64-linux-gnu/libc.so.6
#4  0x00007ffff5b2d68c in ??? () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007ffff5b2dd20 in g_main_context_iteration () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007ffff67a6323 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt6Core.so.6
#7  0x00007ffff6598893 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt6Core.so.6
#8  0x00007ffff659a18a in QCoreApplication::exec() () at /lib/x86_64-linux-gnu/libQt6Core.so.6
#9  0x000055555556c3de in main (argc=<optimized out>, argv=<optimized out>) at ./src/core/main.cpp:67
        scr = {<QApplication> = {<No data fields>}, static staticMetaObject = {d = {superdata = {direct = 0x5555555acb80 <QApplication::staticMetaObject>}, stringdata = 0x55555559ef00 <qt_meta_stringdata_ZN9SingleAppE>, data = 0x55555559ee80 <qt_meta_data_ZN9SingleAppE>, static_metacall = 0x55555556e320 <SingleApp::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, metaTypes = 0x5555555ad320 <qt_incomplete_metaTypeArray<(anonymous namespace)::qt_meta_tag_ZN9SingleAppE_t, QtPrivate::TypeAndForceComplete<SingleApp, std::integral_constant<bool, true> >, QtPrivate::TypeAndForceComplete<void, std::integral_constant<bool, false> >, QtPrivate::TypeAndForceComplete<QString const&, std::integral_constant<bool, false> >, QtPrivate::TypeAndForceComplete<void, std::integral_constant<bool, false> > >>, extradata = 0x0}}, running = false, uniqueKey = {d = {d = 0x5555555fb630, ptr = 0x5555555fb640 u"user-screengrab-3.1.0", size = 23}}, sharedMemory = <incomplete type>, localServer = 0x55555566bd20, static timeout = 1000}
        ScreenGrab = 0x5555555fb5a0

[stefonarch]

You compiled LXQt 2.3 I suppose, to have screengrab 3.1.
I'm running trixie with LXQt git on my PC and screengrab is fine.
So I suggest to recompile it, with it's dependencies first (https://github.com/lxqt/lxqt-build-tools, https://github.com/lxqt/libqtxdg/).

[ogmkp]

I have already built the entire DE with libqt6xdg4=4.3.0 and lxqt-build-tools=2.3.0.
I also use xdg-desktop-portal-wlr=0.8.1 and xdg-desktop-portal-lxqt=1.3.0,
obs-studio can capture the desktop through the integrated pipewire add-on.

Does screengrab have a verbose mode or a way to try to find out what's wrong?

[stefonarch]

There are several command line options you can test

  -h, --help        Displays help on commandline options.                                                     
  --help-all        Displays help, including generic Qt options.                                              
  -v, --version     Displays version information.                                                             
  -f, --fullscreen  Take a fullscreen screenshot                                                              
  -a, --active      Take a screenshot of the active window                                                    
  -r, --region      Take a screenshot of a selection of the screen                                            
  -m, --minimized   Run the application with a hidden main window                                             
  -n, --no-win      Save screenshot and exit, without showing window    

I just updated debian and recompiled it, still fine.
Removing the config folder is another thing to try.

[ogmkp]

I've tried deleting ~/.config/screengrab/screengrab.conf, but it didn't change anything.
Before going any further, I notice that I don't have a screen here:

Is this normal?

[stefonarch]

It's normal if there is only one screen, then no selector is shown.

[ogmkp]

If I leave my mouse over the central area, a tooltip appears:
Screenshot 0x0

If I click on it to open the invisible screenshot, I get:
lximage-qt: Erreur lors de l’ouverture du fichier /tmp/screenshot-286b99eb.jpg : Aucun fichier ou dossier de ce nom

For screengrab, a screenshot was saved to /tmp/screenshot-286b99eb.jpg, but there is nothing there. I checked the permissions for /tmp and its full RW for anyone (and if that weren't the case, I'd have a system that was completely messed up).

If I start with QT_QPA_PLATFORM=xcb screengrab , it behaves normally, but it only captures black screen or windows, even though I have another program running under Xwayland.

[stefonarch]

Screenshots with lximage-qt aren't working under Wayland and are deprecated too, and screengrab under XWayland can't work.

If I leave my mouse over the central area, a tooltip appears:
Screenshot 0x0

This is a good hint, it looks it cannot get the size of the screen in your setup and made a 0x0 one?
It shows the size after the shot:

I suspect a compiling issue/missing/old dependency.

[ogmkp]

If there were missing or outdated dependencies, cmake via CMakeLists.txt would encounter an issue, even though the compilation is successful.

[stefonarch]

I know... but what else? It works fine on my trixie LXQt-git setup...
Your monitor setup? Graphic card?

[ogmkp]

Since there is no verbose output on screengrab, I launched ksnip or flameshot, and the problem is the same, but they do output verbose information:

$ ksnip 
Debug: SingleInstance mode detected, we are the server.
Critical: Unknown wayland platform, using default wayland Image Grabber.
Debug: WaylandImageGrabber selected.
Debug: Loading translation for ksnip from /usr/share/ksnip/translations, success.
Debug: Loading translation for kImageAnnotator from /usr/share/kImageAnnotator/translations, success.
Warning: Wayland does not support QWindow::requestActivate()
Warning: Wayland does not support QWindow::requestActivate()
Warning: This plugin does not support setting window opacity
Critical: Error: L’interface « org.freedesktop.portal.Screenshot » n’existe pas pour l’objet à l’emplacement /org/freedesktop/portal/desktop

$ flameshot 
flameshot: error: Unable to detect desktop environment (GNOME? KDE? Sway? ...)
flameshot: error: Hint: try setting the XDG_CURRENT_DESKTOP environment variable.
flameshot: error: Impossible de capturer l'écran
flameshot: error: Impossible de capturer l'écran
qt.qpa.wayland: Wayland does not support QWindow::requestActivate()

I get:

$ echo $XDG_CURRENT_DESKTOP
LXQt:labwc:wlroots
$ echo $QT_QPA_PLATFORM

I tried:

$ QT_QPA_PLATFORM=wayland screengrab
-> Before pressing + to take a screen capture, the tooltip shows 0x0 without file in /tmp
-> + on screengrab hangs screengrab

$ QT_QPA_PLATFORM=wayland-egl screengrab
-> Screengrab no longer freezes, when I press +, the window reappears without the capture, it is blank.
It still show a tooltip with 0x0 screenshot without file in /tmp

I added a second screen :

$ QT_QPA_PLATFORM=wayland screengrab
-> The screen selector appears in screengrab.
-> + on screengrab hangs screengrab

$ QT_QPA_PLATFORM=wayland-egl screengrab
-> No screen selector, screengrab reacts and come back when I press +, but without the capture, it is blank.
-> Theres a /tmp/screenshot-62d6155a.jpg fil, and I can open it with a double click on the blank aera in screengrab but it all filled with dark but the overall resolution is in (3840x1080 = 2x screens)

There are lots of tickets for the same issue in flameshot and ksnip.
Is it nvidia or xdg-desktop-portal 1.20.3 or xdg-desktop-portal-wlr 0.8.1 or libwayland 1.23.1 or labwc 0.9.3 or libqt6waylandclient6 6.8.2 ? I don't know, I'm taking it one step at a time.

I use a Nvidia GTX 970 with nvidia 580.105.08 driver.

[stefonarch]

Did you test grim / slurp ? Here's a snippet for region:

#!/bin/bash
# screenshot region
grim -g "$(slurp -d)" - | wl-copy -t image/png && notify-send -a grim -i screengrab -t 2000 "Saved tp clipboard"

Screengrab relies on "wlr screencopy protocol", no portal needed, while flameshot needs to be tricked as it doesn't detect LXQt.

[ogmkp]

OK good to know !

grim -g "$(slurp -d)" - | wl-copy -t image/png && notify-send -a grim -i screengrab -t 2000 "Saved tp clipboard"
The screenshot of selected region works and is copied to clipboard

grim - | wl-copy -t image/png copy all the desktop (2 screens) to the clipboard.

[stefonarch]

At least you've a working tool, but it would be nice to understand what fails here but is probably Nvidia-related.

Time ago when screengrab didn't support Wayland yet I wrote https://github.com/qtilities/wshot/ which is based on grim/slurp.