Manage focus between multiple displays on Linux Wayland

leo099

Hi,
I am trying to understand the right way to manage focus when creating QQuickView across multiple monitors.
I have created a minimal app to reproduce what I am trying to do.
main.cpp:

#include <QGuiApplication>
#include <QQuickView>
#include <QScreen>
#include <QQmlContext>

int main(int argc, char *argv[]) {
    QGuiApplication app(argc, argv);

    const QList<QScreen *> screens = QGuiApplication::screens();

    // Create a QQuickView for each screen
    QList<QQuickView *> views;
    QQuickView *primaryScreenView;
    for (QScreen *screen : screens) {
        QQuickView *view = new QQuickView;
        views.append(view);

        view->setScreen(screen);
        view->setResizeMode(QQuickView::SizeRootObjectToView);
        view->setGeometry(screen->geometry());
        view->setFlags(Qt::FramelessWindowHint);

        bool isPrimaryScreen = QGuiApplication::primaryScreen() == screen;
        view->rootContext()->setContextProperty(QStringLiteral("primaryScreen"), QVariant::fromValue(isPrimaryScreen));
        if (isPrimaryScreen) {
            primaryScreenView = view;
        }

        view->setSource(QUrl("qrc:/Main.qml"));

        qInfo() << "Adding view for" << screen->name() << screen->geometry() << " primary: " << isPrimaryScreen;
        view->showFullScreen();
    }

    primaryScreenView->requestActivate();

    return app.exec();
}

Main.qml:

import QtQuick 2.15

Rectangle {
    id: root
    width: 1920
    height: 1080
    color: "lightblue"

    Component.onCompleted: {
        console.log("Screen ", root.Screen.name, " primary: ", primaryScreen);
    }

    Column {
        anchors.centerIn: parent

        Text {
            anchors.horizontalCenter: parent.horizontalCenter
            text: "Hello, World!"
            font.pixelSize: 48
        }

        TextInput {
            id: input
            visible: primaryScreen
            focus: primaryScreen
            anchors.horizontalCenter: parent.horizontalCenter
            text: "Type here"
            font.pixelSize: 24
        }
    }
}

On my Linux machine when running the graphical session on X11 this works as expected having the TextInput on the primary screen focused. But on Wayland the TextInput is not focused, instead the QQuickView on the last monitor to be added is active, and I need to click on the input to focus it.

I found multiple sources claiming that requestActivate() does nothing on Wayland, as the rules governing which window is active are stricter compared to X11, is this true? If so, how can I achieve to have focus on my primary display instead of the last added one?

SGaist

Hi and welcome to devnet,

Just a quick that came to mind: what about adding the primary screen widget as last ?

leo099

@SGaist Yes, I have tried this:
main.cpp:

    // ...
    // Create a QQuickView for each screen
    QList<QQuickView *> views;
    QQuickView *primaryScreenView;
    for (QScreen *screen : screens) {
        // ...
        if (isPrimaryScreen) {
            primaryScreenView = view;
        } else {
            view->showFullScreen();
       }
    }

    primaryScreenView->showFullScreen();
    // ...

and it works.

It feels like a workaround and I do not know if it would be accepted to fix this issue in the SDDM greeter, but I can try opening a pull request since it is an easy enough fix.

SGaist

That's something worth discussing.
I currently don't know the details of the Wayland protocols and how to leverage them from Qt for your situation.