no popups when Virtual Keyboard is included on RPI4

[ulmstefan]

Hi,
I'm developing a Qt Wayland Compositor to launch applications on Raspberry Pi 4 with its official display, and I also need support for Virtual Keyboard (compositor-side). The back-end is eglfs.

I'm starting with the server-side-decoration example, which is close to my needs, mixing it with pure-qml to add Virtual Keyboard support.

The virtual keyboard works as expected (QT_IM_MODULE=qtvirtualkeyboard is set for the compositor), but the popups (e.g. the entries of a dropdown menu) stop working. Or better: just a small 1x1 box is show at the top-left corner of the application. If I disable the loading of the virtual keyboard, they work fine again.

In the logs I get:

virtual void QWaylandXdgPopupPrivate::xdg_popup_grab(QtWaylandServer::xdg_popup::Resource*, wl_resource*, uint32_t) Not implemented
virtual void QWaylandXdgPopupPrivate::xdg_popup_destroy(QtWaylandServer::xdg_popup::Resource*) Not implemented

In the code I've included the virtual keyboard in the CMakeLists.txt file (find_package, target_link_libraries and resources) and then I have added this keyboard.qml file:

import QtQuick
import QtQuick.VirtualKeyboard

InputPanel {
    visible: active
    y: active ? parent.height - height : parent.height
    anchors.left: parent.left
    anchors.right: parent.right
}

The main.qml is quite simple; the path to the keyboard loader is WaylandCompositor -> WaylandOutput.window=Window -> WaylandMouseTracker -> Loader.

The complete code:

import QtQuick
import QtQuick.Window
import QtQuick.Layouts
import QtWayland.Compositor
import QtWayland.Compositor.XdgShell

WaylandCompositor {
    id: compositor
    WaylandOutput {
        id: output
        property bool isNestedCompositor: Qt.platform.pluginName.startsWith("wayland") || Qt.platform.pluginName === "xcb"
        sizeFollowsWindow: output.isNestedCompositor
        window: Window {
            id: win
            width: 800
            height: 480
            visible: true

            WaylandMouseTracker {
                id: mouseTracker
                anchors.fill: parent
                windowSystemCursorEnabled: output.isNestedCompositor

                Rectangle {
                    id: background
                    anchors.fill: parent
                    gradient: "MorpheusDen"
                }

                Repeater {
                    model: shellSurfaces
                    // ![decoration]
                    Column {
                        id: chrome
                        width: shellSurfaceItem.implicitWidth
                        Rectangle {
                            visible: modelData.toplevel.decorationMode === XdgToplevel.ServerSideDecoration
                            width: parent.width
                            height: 30
                            gradient: "HeavyRain";
                            Text {
                                text: modelData.toplevel.title
                                anchors.centerIn: parent
                            }
                            Item {
                                anchors.right: parent.right
                                width: 30
                                height: 30
                                Text { text: "X"; anchors.centerIn: parent }
                                TapHandler {
                                    onTapped: modelData.toplevel.sendClose()
                                }
                            }
                            DragHandler {
                                target: chrome
                            }
                        }
                        ShellSurfaceItem {
                            id: shellSurfaceItem
                            moveItem: parent
                            shellSurface: modelData
                            onSurfaceDestroyed: shellSurfaces.remove(index)
                        }
                    }
                    // ![decoration]
                }

                // Virtual Keyboard
                // ![keyboard]
                Loader {
                    anchors.fill: parent
                    source: "keyboard.qml"
                }
                // ![keyboard]
            }
        }
    }

    // ![XdgShell]
    XdgShell {
        onToplevelCreated: (toplevel, xdgSurface) => shellSurfaces.append({shellSurface: xdgSurface});
    }
    XdgDecorationManagerV1 {
        preferredMode: XdgToplevel.ServerSideDecoration
    }
    // ![XdgShell]
    ListModel { id: shellSurfaces }

    TextInputManager {}
    QtTextInputMethodManager {}
}

When I click a dropdown menu, the result is this (notice the pixels at the top-left corner of the application window); the virtual keyboard was correctly closed:

Any idea about what I'm doing wrong?

Thanks in advance!

[Ralf_G]

Hello,
I ran into the same log error messages, when handling a ComboBox in a Qt program running on a custom Compositor. @ulmstefan any outcome to this?