Bug with transparent apps and possible workarounds

[johndoe]

Hello,
I think, it would be really nice to have transparent apps. At least for a terminal or for a messenger it would be a nice feature, if you could see the Lomiri background you selected.
Unfortunately this does not seem to work on my device (Pixel 3a with 20.04 OTA-2) with following code:

import QtQuick 2.6
import QtQuick.Window 2.2
import QtQuick.Layouts 1.3
import QtQuick.Controls 2.2
import Lomiri.Components 1.3
import Qt.labs.settings 1.0

ApplicationWindow {
	flags: Qt.FramelessWindowHint | Qt.WA_TranslucentBackground
	title: "Test-App"
	color: "#00000000"
}

The black image is how the app actually looks like and the next picture right of it is the screenshot that probably appears white, because it is a picture with transparent colors. The app only gets actually transparent, when I go to the app overview.

This problem also seems to exist with the terminal app for some time now:
https://gitlab.com/ubports/development/apps/lomiri-terminal-app/-/issues/57

Is it for everyone like this or is this only on some devices the case?

As a workaround, it would be nice, if app developers could easily get the selected Lomiri background from somewhere and place it in their app as a background.

I tried:

gsettings get org.gnome.desktop.background picture-uri

But this only gave me the default background ('file:///usr/share/backgrounds/lomiri-default-background.png') and not the one, that was selected by me.

Does someone know where to find for the current background or does someone have a better solution?

[kugiigi]

@johndoe Honestly, I'm not sure why Canonical decided to put an opaque background behind apps but disables it on tablets or when the side-stage is enabled. So at the moment, there's no way to do it via the app. You have to hack Lomiri to disable it or configure your device as a tablet.

I enabled side-stage on my phone so transparent app does work

[johndoe]

@kugiigi Oh wow, so it is actually possible. I thought it would be a some complicated problem with Lomiri.
What is "side-stage" and how do I enable it? How would you need to hack Lomiri?

[kugiigi]

@johndoe You can configure your device as a tablet. Try checking here /etc/device-info or /etc/ubuntu-touch-session.d/. However, it also has other effects such as a different lockscreen layout.

Side-stage is the split screen-like feature in Lomiri. It's currently tied with the tablet configuration so it's only enabled if your device is detected as a tablet. You can try hacking Lomiri's code if you're fine with that. The files are at /usr/share/lomiri and the relevant codes are here https://github.com/kugiigi/jerk-packages/blob/673d73e7e9cbeaaa39dc99aa9148318da6530619/Lomiri/Lomiri_Plus/focal/MOD/Shell.qml#L3903

This however is out of scope of the app development

[Keneda]

@kugiigi
You can force tablet mode with UTTT also.

[kugiigi]

@Keneda No, that's only for stage or windowed mode which is different from being configured as a tablet.