Qt5 QML App not visible when change the resolution ?

[Alex_wang]

Hi ,
My app is developed with QML and display with the plugin "eglfs-kms-egldevice" on TX1.
When I change the device TX1 resolution from 1080P to 720P (or 720P to 1080P),
my app is not visible on the screen ,but it can response the keyboard event.

I guess :
when the resolution changes , the egl surface is ont update. but I do not know how to update it except for restarting the app

[Alex_wang]

@Alex_wang

Hi,

can Qt5 have a way for monitoring the resolution's change,when I change the device TX1 resolution from 1080P to 720P (or 720P to 1080P) ?

[SGaist]

Hi,

Is your application moved outside of the visible part of the screen ?

[Alex_wang]

@SGaist
I'm not sure for it to be invisible or move outside of the visible part of the screen.
I have read the eglfs plugin source ,and find that the egl surface or screen or window depending on the resolution is created
by QGuiApplicationPrivate::init -->QGuiApplicationPrivate::createPlatformIntegration().
so ,when my app displays successfully with the resolution 1080P,the egl surface or screen or window is created with the 1080P.
But when I change the resolution to 720P, the egl surface or screen or window has still been depending on the 1080P.
Then my app displays unsuccessfully , is invisible .....

[Alex_wang]

@SGaist

Does it have an event in Qt5.9.3 that notices the connector resolution changing ?

[Devopia53]

@Alex_wang

Yes, of course. Read the following document.

QScreen
Screen

like this:

#include <QScreen>
[...]
QScreen     *screen = QApplication::primaryScreen();
QObject::connect(screen, &QScreen::geometryChanged, [](const QRect &geometry){ qDebug() << geometry; });
[...]

[Alex_wang]

@Devopia53 said in Qt5 QML App not visible when change the resolution ?:

QObject::connect(screen, &QScreen::geometryChanged, [](const QRect &geometry){ qDebug() << geometry; });

Hi, it is not helpful for me.

when I change the resolution, the screen (QApplication::primaryScreen()) is not changed....

[jsulm]

@Alex_wang Do you mean the QScreen::geometryChanged signal is not emitted?

[SGaist]

By the way, how are you changing the resolution ?

[Alex_wang]

@SGaist
change the resolution by an app "drm_modeset":

sudo ./drm_modeset -s 1920x1080@60

[Alex_wang]

after changed the resolution, the surface or screen or window for qt5 app is still depending on last resolution.
the reason is on four floor

[SGaist]

See here and the QT_QPA_EGLFS_ALWAYS_SET_MODE environment variable.

[Alex_wang]

@SGaist
I have got it . It means I still have to relaunch the application.

[SGaist]

Do you have any other application running on your system ?

[Alex_wang]

@SGaist
The decoded video is also rendered by DRM, which is running on my system.

[SGaist]

You have to give more details about your system and what it does.

[Michael Chen]

@Alex_wang
Have you found a solution? I'm also having the same problem.