Widget Properties

Plasmoid property group

As discussed in the main.qml setup widget section, when you import org.kde.plasma.plasmoid 2.0, the main Item in your widget will have the Plasmoid (with a capital) property group similar to when you import QtQuick.Layouts 1.0. This Plasmoid property group has properties from AppletInterface which inherits a few properties from PlasmaQuick::AppletQuickItem.

plasmoid context property

You can reference a property from the Plasmoid.___ property group by the root Item { id: widget } of the widget with widget.Plasmoid.___. An easier method is to use the global context property plasmoid (lowercase) which is dynamically defined at runtime when the property group is imported.

import QtQuick 2.0
import org.kde.plasma.components 3.0 as PlasmaComponents3
import org.kde.plasma.plasmoid 2.0
Item {
    id: widget
    Plasmoid.icon: 'starred-symbolic'
    Plasmoid.fullRepresentation: PlasmaComponents3.Label {
        text: plasmoid.icon
        // OR
        // text: widget.Plasmoid.icon
    }
}

Plasmoid properties

Plasmoid.compactRepresentation

The compact representation uses DefaultCompactRepresentation.qml by default. To summarize, it:

• Draws the plasmoid.icon using a Kirigami.Icon
• Defines a MouseArea to toggle the expanded property which displays the full representation.

https://invent.kde.org/plasma/plasma-desktop/-/blob/master/desktoppackage/contents/applet/CompactApplet.qml

Plasmoid.fullRepresentation

Plasmoid.preferredRepresentation: Plasmoid.fullRepresentation

import QtQuick 2.0
import QtQuick.Layouts 1.0
import org.kde.plasma.core 2.0 as PlasmaCore
import org.kde.plasma.components 2.0 as PlasmaComponents
import org.kde.plasma.plasmoid 2.0

Item {
    // Always display the compact view.
    // Never show the full popup view even if there is space for it.
    Plasmoid.preferredRepresentation: Plasmoid.compactRepresentation

    Plasmoid.fullRepresentation: Item {
        Layout.minimumWidth: label.implicitWidth
        Layout.minimumHeight: label.implicitHeight
        Layout.preferredWidth: 640 * PlasmaCore.Units.devicePixelRatio
        Layout.preferredHeight: 480 * PlasmaCore.Units.devicePixelRatio
        
        PlasmaComponents.Label {
            id: label
            anchors.fill: parent
            text: "Hello World!"
            horizontalAlignment: Text.AlignHCenter
        }
    }
}

Plasmoid.icon

import QtQuick 2.0
import org.kde.plasma.plasmoid 2.0

Item {
    id: widget
    property bool hasUnread: true
    Plasmoid.icon: hasUnread ? "mail-unread" : "mail-message"

    Timer {
        interval: 1000
        repeat: true
        running: true
        onTriggered: widget.hasUnread = !widget.hasUnread
    }
}

Plasmoid.configuration

import QtQuick 2.0
import org.kde.plasma.components 3.0 as PlasmaComponents3
import org.kde.plasma.plasmoid 2.0

RowLayout {
    id: widget
    PlasmaComponents.Label {
        text: i18np("%1 Click", "%1 Clicks", plasmoid.configuration.numClicked)
    }
    PlasmaComponents3.Button {
        icon.name: "value-increase-symbolic"
        text: i18n("Add")
        onClicked: plasmoid.configuration.numClicked += 1
    }
}

Plasmoid.backgroundHints

PlasmaCore.Types.NoBackground | PlasmaCore.Types.ConfigurableBackground

PlasmaCore.IconItem {
    colorGroup: PlasmaCore.ColorScope.colorGroup
}

import QtQuick 2.0
import org.kde.plasma.core 2.0 as PlasmaCore
import org.kde.plasma.plasmoid 2.0

Item {
    id: widget
    Plasmoid.backgroundHints: PlasmaCore.Types.NoBackground
}

import QtQuick 2.0
import QtQuick.Layouts 1.0
import org.kde.plasma.core 2.0 as PlasmaCore
import org.kde.plasma.components 2.0 as PlasmaComponents3
import org.kde.plasma.plasmoid 2.0

Item {
    id: widget
    Plasmoid.icon: 'starred-symbolic'
    Plasmoid.backgroundHints: PlasmaCore.Types.StandardBackground | PlasmaCore.Types.ConfigurableBackground
    // Plasmoid.backgroundHints: PlasmaCore.Types.ShadowBackground | PlasmaCore.Types.ConfigurableBackground
    // Plasmoid.backgroundHints: PlasmaCore.Types.NoBackground | PlasmaCore.Types.ConfigurableBackground

    Plasmoid.preferredRepresentation: Plasmoid.fullRepresentation
    Plasmoid.fullRepresentation: RowLayout {
        PlasmaCore.IconItem {
            source: plasmoid.icon
            colorGroup: PlasmaCore.ColorScope.colorGroup
            Layout.fillHeight: true
            Layout.preferredWidth: height
        }
        PlasmaComponents3.Label {
            text: "Text"
            font.pointSize: 30
        }
    }
}

metadata.json

The common metadata.json properties are covered in the setup widget section.

metadata.desktop is the older format while metadata.json is the newer replacement format. The .desktop file is simpler to script using kreadconfig5 which is the reason why this tutorial prefers it in certain places like translations.

You can read the generated C++ API Documentation for metadata.json for the json schema. The full list of properties for the older metadata.desktop properties for widgets is defined in the Plasma/Applet service type.

Name, Description

{
    "KPlugin": {
        "Description": "Month display with your appointments and events",
        "Description[fr]": "Vue mensuelle avec vos rendez-vous et évènements",
        "Name": "Calendar",
        "Name[fr]": "Calendrier"
    }
}

[Desktop Entry]
Name=Calendar
Name[fr]=Calendrier
Comment=Month display with your appointments and events
Comment[fr]=Vue mensuelle avec vos rendez-vous et évènements

Icon

Icon is the icon name associated with the widget. You can search for icon names in the /usr/share/icon folder. You can also look for an icon name by right clicking your app launcher widget then editing the icon in its settings. It uses a searchable interface and lists them by category. Plasma's SDK also has the Cuttlefish app which you can install with sudo apt install plasma-sdk.

metadata.json

{
    "KPlugin": {
        "Icon": "office-calendar",
    }
}

metadata.desktop

[Desktop Entry]
Icon=office-calendar

Id

❯ kpackagetool5 --type Plasma/Applet --list
Listing service types: Plasma/Applet in ~/.local/share/plasma/plasmoids/
com.github.zren.helloworld

❯ kpackagetool5 --type Plasma/Applet --list --global
Listing service types: Plasma/Applet in /usr/share/plasma/plasmoids/
org.kde.desktopcontainment
org.kde.kdeconnect
org.kde.kscreen
org.kde.milou
org.kde.panel
org.kde.plasma.activitybar
org.kde.plasma.activitypager
org.kde.plasma.addons.katesessions
...

~/.local/share/plasma/plasmoids/com.github.zren.helloworld/
/usr/share/plasma/plasmoids/com.github.zren.helloworld/

{
    "KPlugin": {
        "Id": "com.github.zren.helloworld",
    }
}

[Desktop Entry]
X-KDE-PluginInfo-Name=com.github.zren.helloworld

Category

The Category (or X-KDE-PluginInfo-Category in metadata.desktop) is used to filter widgets in the widget list.

{
    "KPlugin": {
        "Category": "Date and Time",
    }
}

[Desktop Entry]
X-KDE-PluginInfo-Category=Date and Time

• Accessibility: tools that help those with special needs or disabilities use their computer
• Application Launchers: application starters and file openers.
• Astronomy: anything to do with the night sky or other celestial bodies.
• Date and Time: clocks, calendars, scheduling, etc
• Development Tools: tools and utilities to aid software developers
• Education: teaching and educational aides
• Environment and Weather: add-ons that display information regarding the weather or other environmentally related data
• Examples: samples that are not meant for production systems
• File System: anything that operates on files or the file system as its primary purpose, such as file watchers or directory listings. Simply using a file as storage does not qualify the add-on for this category.
• Fun and Games: for games and amusements
• Graphics: for add-ons where displaying images, photos or graphical eye candy is the primary purpose
• Language: add-ons whose primary purpose is language related, such as dictionaries and translators.
• Mapping: geography and geographic data add-ons
• Multimedia: music and video.
• Online Services: add-ons that provide an interface to online services such as social networking or blogging sites. If there is another more appropriate category for the add-on given the topic (e.g. mapping if the applet's purpose is to show maps), even if the data is retrieved from the Internet prefer that other category over this one.
• System Information: display and interaction with information about the computer such as network activity, hardware health, memory usage, etc
• Utilities: Useful tools like calculators
• Windows and Tasks: managers for application windows and/or tasks, such as taskbars

This list was taken from: https://techbase.kde.org/Projects/Plasma/PIG

KPackageStructure

{
    "KPackageStructure": "Plasma/Applet"
}

[Desktop Entry]
X-KDE-ServiceTypes=Plasma/Applet

X-Plasma-API, X-Plasma-MainScript

{
    "X-Plasma-API": "declarativeappletscript",
    "X-Plasma-MainScript": "ui/main.qml"
}

[Desktop Entry]
X-Plasma-API=declarativeappletscript
X-Plasma-MainScript=ui/main.qml

X-Plasma-Provides (Alternatives)

A Plasmoid can specify the type of functionality it offers, for example whether it's a clock, an application launcher, etc. This mechanism is used to list alternative plasmoids for a certain function. When you open the context menu of the Application Launcher (aka kickoff) in the Plasma desktop panel, you'll see that a number of different Plasmoids are offered here as alternatives, like the Application Menu (aka kicker) and Application Dashboard (aka kickerdash). All three of these widgets define:

{
    "X-Plasma-Provides": [
        "org.kde.plasma.launchermenu"
    ]
}

[Desktop Entry]
X-Plasma-Provides=org.kde.plasma.launchermenu

These "Provides" are in fact arbitrary, so you can choose your own here. The field accepts multiple values separated by a comma. Here are some possible values that are used throughout Plasma:

• org.kde.plasma.launchermenu: App Launcher Menus
• org.kde.plasma.multimediacontrols: Multimedia controls
• org.kde.plasma.time: Clocks
• org.kde.plasma.date: Calendars
• org.kde.plasma.time,org.kde.plasma.date: Clocks with calendars (Eg: Digital Clock)
• org.kde.plasma.powermanagement: Power management (Eg: Battery and Brightness)
• org.kde.plasma.notifications: Notifications
• org.kde.plasma.removabledevices: Removable devices, auto mounter, etc.
• org.kde.plasma.multitasking: Task switchers
• org.kde.plasma.virtualdesktops: Virtual desktop switcher
• org.kde.plasma.activities: Switchers for Plasma activities
• org.kde.plasma.trash: Trash / file deletion

You can search plasma's code for more examples:

• Search plasma-workspace for X-Plasma-Provides
• Search plasma-desktop for X-Plasma-Provides
• Search kdeplasma-addons for X-Plasma-Provides

X-Plasma-NotificationArea (System Tray)

The Media Controller widget serves as a good example since it uses most of the systemtray metadata features. Its metadata contains the following:

{
    "KPlugin": {
        "EnabledByDefault": true
    },
    "X-Plasma-DBusActivationService": "org.mpris.MediaPlayer2.*",
    "X-Plasma-NotificationArea": "true",
    "X-Plasma-NotificationAreaCategory": "ApplicationStatus"
}

[Desktop Entry]
X-KDE-PluginInfo-EnabledByDefault=true
X-Plasma-NotificationArea=true
X-Plasma-NotificationAreaCategory=ApplicationStatus
X-Plasma-DBusActivationService=org.mpris.MediaPlayer2.*

By specifying X-Plasma-NotificationArea, this widget will be found by the systemtray widget.

EnabledByDefault will make sure it's enabled in the systemtray by default.

It's prudent for the widget to also set the X-Plasma-NotificationAreaCategory so that the icons are grouped together. Its allowed values are:

• ApplicationStatus: indicates that this item represents an active application
• Hardware: indicates that this item allows managing hardware (could be a battery monitor or the wifi applet)
• SystemServices: indicates that this item shows information about system services, for example the status of file indexing, software updates, etc.

You can search plasma's code for more examples:

• Search plasma-workspace for X-Plasma-NotificationArea
• Search plasma-desktop for X-Plasma-NotificationArea
• Search kdeplasma-addons for X-Plasma-NotificationArea

X-Plasma-DBusActivationService

X-Plasma-DBusActivationService will load and unload widgets in the systemtray automatically when a DBus service becomes available or is stopped. This is very convenient to load widgets automatically, so the user doesn't have to explicitly go to the notification area settings and enable or remove a widget.

An example of this is the Media Controller widget, which is auto-loaded as soon as an application starts offering the org.mpris.MediaPlayer2 DBus service in the session. As you can see in its metadata.json file, X-Plasma-DBusActivationService accepts wildcards which makes it a bit easier to match DBus names. This key can also be very useful to avoid having a widget loaded when it's unnecessary, so it can help to avoid visual clutter and wasted memory.

{
    "X-Plasma-DBusActivationService": "org.mpris.MediaPlayer2.*"
}

[Desktop Entry]
X-Plasma-DBusActivationService=org.mpris.MediaPlayer2.*

Search plasma-workspace for X-Plasma-DBusActivationService for more examples.