Same code different GUI?

Mucip

Hi,
I have written a program with Qt 6 on Debian 13.
I moved the same code and recompile on Debian 12.
Both use KDE but I see different GUI on the screen. Why?

By the way I use;

w.setWindowState(Qt::WindowFullScreen);

in main.cpp

Debian 12:

Debian 13:

Regards,
Mucip:)

Christian Ehrlicher

I would say the style is different.

Mucip

Hi,
What you mean? Which style?

Do you mean KDE Plazma Style?

SGaist

Hi,

Likely yes.
Start your application with the QT_DEBUG_PLUGINS environment variable set to 1.
You will be able to see which plugins get loaded and compare between both systems.

Mucip

I forgot. I did not say that I run Debain12 on single board computer. RockPi ?!
Is the reason be this?

SGaist

Board or full computer should not make a difference in that case. You likely have two different versions of KDE and Plasma running which may be using a different style hence the suggestion to check which one is being loaded.

Mucip

OK. I see many changes on both loading things. And very difficult to see reason for me?!

But I can not add both txt files here?!

But I see in first lines:
Debian12 uses;
QVncIntegrationPlugin
QXcbIntegrationPlugin
QVkKhrDisplayIntegrationPlugin

Debian13 uses;
QXcbIntegrationPlugin
QLinuxFbIntegrationPlugin
QOffscreenIntegrationPlugin

Mucip

Or should I transfer to basic desktop something like xfce?

Mucip

I started QT_QPA_PLATFORM=eglfs mode I mean without Desktop but nothing changed?!

Mucip

Any suggestion about my problem?

SGaist

Can you describe your setup with more precision ?
Which exact version of Qt are you using on each system ?
Which exact version of KDE are you using on each ?
Which style does get loaded and used ?
How are you starting your application ?

Mucip

Dear @SGaist ,
I wrote program in QtCreator 6.11.2 in Debian 13.
I copy code to Debain12. Because RockPi use Debian 12. And I use qmak6 to compile in Debian12.
I run compiled program from CLI in Debian12.

Debian 12KDE:

Debian 13 KDE:

I use Breeze Dark on both system.

Regards,
Mucip:)

SGaist

So I would take that you are using 6.4.2 on Debian 12 ? That means a gap of four minor versions between the two.
That does not fully explain the difference but there might have been fixes between the two versions.
Are you using QML for you UI ?
Also, which style gets loaded ?

Mucip

I use UI not QML.
I did not understan your last question. Style? In Qt or in Plasma?

Regards,
Mucip:)

SimonSchroeder

According to your screenshots on Debian 12 you are using KDE 5, Qt 5, and X11 and on Debian 13 you are using KDE 6, Qt 6, and Wayland.

Besides the totally different versions of KDE and Qt, also the switch from X11 to Wayland can have a huge impact.

Mucip

@SimonSchroeder
But in any case I recompile the codes with qmake6 in Debian12. It should be same I think.
Or Should I install Qtcreator in Debian 12? But I don't think that it changes something. Because I recompile it?
It must be something other reason?

Regards,
Mucip:)

Mucip

Well, I just installed Qt5 Framework on Rock Pi Debian12.
$ sudo apt install qtbase5-dev qtcreator

I use qmake (not qmake6!) incase of compile program. But nothing changed.
Than I tried to open pro file in QtFramework but could not open even?!
Project error: cannot run compile 'clang++'.output
Maybe you forgot to setup the environment?

Error while parsing file.... xx.pro

And I don't know why I see about window:
Qt Creator 9.0.2
Based on Qt 6.4.2 (GCC 12.2.0, arm64)

Situation is getting strange step by step... :)

SGaist

@Mucip said in Same code different GUI?:

I use UI not QML.
I did not understan your last question. Style? In Qt or in Plasma?

Regards,
Mucip:)

Style as in QStyle. If memory serves well KDE has its own.

Mucip

@SGaist ,
I don't know about style? Please could you guide me how to control it?

Regards,
Mucip:)

Christian Ehrlicher

You can pass the style you want to use by command line ( https://doc.qt.io/qt-6/qapplication.html#QApplication-1 ) or by code ( https://doc.qt.io/qt-6/qapplication.html#setStyle )