quickshell

name: quickshell description: Patterns and best practices for building Quickshell-based Wayland desktop shells with QML, covering architecture, services, components, config, state management, animations, and C++ plugin integration

Project Structure

Quickshell projects follow a modular architecture:

shell.qml              # Entry point - extends ShellRoot
components/            # Reusable UI primitives
  controls/            # Interactive widgets (buttons, sliders, switches)
  containers/          # Layout containers (windows, list views)
  effects/             # Visual effects (elevation, shadows, masks)
modules/               # Feature modules
  bar/                 # Status bar
  drawers/             # Panel/orchestration system
  launcher/            # Application launcher
  dashboard/           # Top panel
  sidebar/             # Notification sidebar
  lock/                # Lock screen
  controlcenter/       # Settings UI
services/              # Singleton state managers
  Audio.qml
  Notifs.qml
  Network.qml
  Hypr.qml
  Colours.qml
  ...
config/                # Configuration system
  Config.qml
  AppearanceConfig.qml
  ...
utils/                 # Utility singletons
  Icons.qml
  Paths.qml
  Searcher.qml
plugin/                # C++ QML plugins
  src/Caelestia/

Entry point pattern:

// shell.qml
import Quickshell
import "modules"
import "modules/drawers"

ShellRoot {
    Background {}
    Drawers {}
    Lock {}
    Shortcuts {}
}

QML Conventions

Required Pragmas

pragma Singleton
pragma ComponentBehavior: Bound

Naming Conventions

• Files: PascalCase matching component name (StyledRect.qml)
• Singletons: PascalCase accessed directly by name (Hypr.qml)
• Root id: Always id: root
• Inline components: component Name: BaseType {}
• Imports: Use qs. prefix for local modules (qs.services, qs.config)

Type Annotations

readonly property real volume: sink?.audio?.volume ?? 0

function setVolume(newVolume: real): void {
    // implementation
}

signal valueChanged(newValue: real)

Null Safety

// Optional chaining + nullish coalescing
sink?.audio?.volume ?? 0
monitor?.name ?? "Unknown"

Service Architecture

Singleton Service Pattern

// services/MyService.qml
pragma Singleton
pragma ComponentBehavior: Bound

import Quickshell

Singleton {
    id: root

    // State properties
    readonly property real volume: sink?.audio?.volume ?? 0

    // IPC Handler for CLI access
    IpcHandler {
        target: "myService"
        function getVolume(): real { return root.volume }
        function setVolume(value: real): void { ... }
    }

    // Global keyboard shortcut
    CustomShortcut {
        name: "volumeUp"
        description: "Increase volume"
        onPressed: root.incrementVolume()
    }

    // Hot-reload safe persistent state
    PersistentProperties {
        id: props
        property bool enabled: true
        reloadableId: "myService"
    }
}

Communication Patterns

Hyprland Socket IPC:

// Use Hyprland singleton
Quickshell.Hyprland {
    id: hypr
}

Connections {
    target: hypr
    function onRawEvent(event: string): void {
        // Handle events
    }
}

PipeWire Audio:

import Quickshell.Services.Pipewire as Pw

Pw.Pipewire {
    id: pipewire
}

Connections {
    target: pipewire.defaultAudioSink
    function onAudioChanged(): void {
        // React to volume changes
    }
}

D-Bus (Notifications):

import Quickshell.Services.Notifications as Notifs

Notifs.NotificationServer {
    onNotification: (notification) => {
        // Handle notification
    }
}

Subprocess Execution:

import Quickshell.Io

Process {
    id: process
    command: ["brightnessctl", "g"]

    stdout: StdioCollector {
        onStreamFinished: {
            const output = text.trim()
            // Process output
        }
    }
}

File Watching:

import Quickshell.Io

FileView {
    path: Paths.config + "/settings.json"
    watchChanges: true
    onLoaded: (data) => {
        // React to file changes
    }
}

HTTP Requests (from C++ plugin):

import Caelestia

Requests.get(url, (response) => {
    // Handle response
})

Component Design System

Animation Primitives

// Anim.qml - NumberAnimation with M3 curves
NumberAnimation {
    duration: Appearance.anim.durations.normal
    easing.bezierCurve: Appearance.anim.curves.standard
}

// CAnim.qml - ColorAnimation variant
ColorAnimation {
    duration: Appearance.anim.durations.normal
    easing.bezierCurve: Appearance.anim.curves.standard
}

Styled Base Components

// StyledRect.qml
Rectangle {
    color: "transparent"
    Behavior on color { CAnim {} }
}

// StyledText.qml
Text {
    renderType: Text.NativeRendering
    color: Colours.palette.m3onSurface
    font.family: Appearance.font.family.normal
    font.pixelSize: Appearance.font.size.normal
    Behavior on color { CAnim {} }
}

StateLayer (Material Ripple)

// components/StateLayer.qml
MouseArea {
    id: root
    anchors.fill: parent
    hoverEnabled: true

    property color colour: Colours.tPalette.m3onSurface

    StyledClippingRect {
        id: layer
        anchors.fill: parent
        radius: parent.radius
        opacity: root.pressed ? 0.12 : root.containsMouse ? 0.08 : 0
        color: root.colour
        Behavior on opacity { Anim {} }
    }

    function onClicked(): void {} // Override point
    onClicked: onClicked()
}

Material Icon

// components/MaterialIcon.qml
StyledText {
    id: root
    property string icon: "settings"
    property int fill: 0
    property int grade: 0
    property int opticalSize: 24

    text: root.icon
    font.family: "Material Symbols Rounded"
    font.variableAxes: ({
        "FILL": root.fill,
        "GRAD": root.grade,
        "opsz": root.opticalSize
    })
}

StyledWindow (Wayland Layer Shell)

// components/containers/StyledWindow.qml
import Quickshell
import Quickshell.Wayland

PanelWindow {
    id: root
    required property string name

    namespace: `caelestia-${root.name}`
    layer: Layer.Top

    margin {
        top: Config.bar.persistent ? Appearance.padding.normal : 0
    }

    ExclusionMode {
        id: exclusionMode
    }
}

Module Patterns

Wrapper/Content/Background Triad

// modules/sidebar/Wrapper.qml
StyledRect {
    id: root
    required property PersistentProperties visibilities

    implicitWidth: 0

    states: State {
        name: "visible"
        when: root.visibilities.sidebar && Config.sidebar.enabled
        PropertyChanges { root.implicitWidth: Config.sidebar.width }
    }

    transitions: [
        Transition {
            from: ""; to: "visible"
            Anim { property: "implicitWidth" }
        },
        Transition {
            from: "visible"; to: ""
            Anim { property: "implicitWidth" }
        }
    ]

    // Lazy-loaded content
    Loader {
        id: content
        active: false
        Component.onCompleted: active = Qt.binding(() =>
            root.visibilities.sidebar || root.state === "visible")
        sourceComponent: Content { visibilities: root.visibilities }
    }
}

// modules/sidebar/Content.qml
ColumnLayout {
    required property PersistentProperties visibilities

    // Actual UI content
}

// modules/sidebar/Background.qml
ShapePath {
    // Background shape definition
}

Per-Screen Instantiation

// Create instances for each screen
Variants {
    model: Quickshell.screens
    Scope {
        required property ShellScreen modelData

        StyledWindow {
            screen: modelData
            // Window content
        }

        PersistentProperties {
            id: visibilities
            property bool bar: false
            property bool sidebar: false
            Component.onCompleted: Visibilities.load(modelData, visibilities)
        }
    }
}

Lazy Loading

// Conditional Loader activation
Loader {
    id: content
    active: false
    Component.onCompleted: {
        active = Qt.binding(() => root.visible || root.animating)
    }
    sourceComponent: Content {}
}

// Timer-delayed initialization
Timer {
    running: true
    interval: Appearance.anim.durations.extraLarge
    onTriggered: {
        content.active = Qt.binding(() => shouldLoad())
    }
}

// LazyLoader for dialogs
LazyLoader {
    function open(): void { activeAsync = true; }
    function close(): void { rejected(); }

    FloatingWindow {
        // Dialog content
    }
}

Animation System

Implicit Behavior Animations

Rectangle {
    id: root
    color: Colours.palette.m3surface
    radius: Appearance.rounding.normal

    Behavior on color { CAnim {} }
    Behavior on radius { Anim {} }
    Behavior on implicitWidth {
        Anim { duration: Appearance.anim.durations.large }
    }
    Behavior on opacity { Anim {} }
}

Material Design 3 Curves

// Standard - for property changes
easing.bezierCurve: [0.2, 0, 0, 1]  // standard

// Emphasized - for exit/close animations
easing.bezierCurve: [0.2, 0, 0, 1]  // emphasized

// Expressive Spatial - for enter/open animations
easing.bezierCurve: [0.05, 0.7, 0.1, 1]  // expressiveDefaultSpatial

Enter vs Exit Curves

transitions: [
    // Opening: Use expressive spatial for lively entrance
    Transition {
        from: ""; to: "visible"
        Anim {
            property: "implicitWidth"
            easing.bezierCurve: Appearance.anim.curves.expressiveDefaultSpatial
        }
    },
    // Closing: Use emphasized for graceful exit
    Transition {
        from: "visible"; to: ""
        Anim {
            property: "implicitWidth"
            easing.bezierCurve: Appearance.anim.curves.emphasized
        }
    }
]

States/Transitions for Panels

Item {
    id: root
    implicitHeight: 0

    states: State {
        name: "visible"
        when: shouldShow
        PropertyChanges { root.implicitHeight: contentHeight }
    }

    transitions: [
        Transition {
            from: ""; to: "visible"
            Anim { property: "implicitHeight" }
        },
        Transition {
            from: "visible"; to: ""
            Anim { property: "implicitHeight" }
        }
    ]
}

Sequential Animations

SequentialAnimation {
    id: expandAnim
    PropertyAction { target: root; property: "animating"; value: true }
    Anim { property: "implicitHeight"; to: targetHeight }
    ScriptAction {
        script: root.implicitHeight = Qt.binding(() => content.implicitHeight)
    }
    PropertyAction { target: root; property: "animating"; value: false }
}

List Item Remove Animation

ListView {
    delegate: Item {
        ListView.onRemove: removeAnim.start()

        SequentialAnimation {
            id: removeAnim
            PropertyAction { property: "ListView.delayRemove"; value: true }
            Anim { property: "x"; to: width * 2 }
            PropertyAction { property: "ListView.delayRemove"; value: false }
        }
    }
}

Configuration System

JsonAdapter + JsonObject

// config/Config.qml
pragma Singleton
import Quickshell.Io

Singleton {
    id: root

    FileView {
        id: fileView
        path: Paths.config + "/shell.json"
        watchChanges: true
        onLoaded: (data) => {
            adapter.json = data
            Toaster.toast("Config loaded", "", "settings", "success")
        }
    }

    JsonAdapter {
        id: adapter
        property AppearanceConfig appearance: AppearanceConfig {}
        property GeneralConfig general: GeneralConfig {}
        property BarConfig bar: BarConfig {}
        // ... more sections
    }

    function save(): void {
        saveTimer.restart()
    }

    Timer {
        id: saveTimer
        interval: 500  // Debounce
        onTriggered: {
            const config = {
                appearance: adapter.appearance.serialize(),
                general: adapter.general.serialize(),
                bar: adapter.bar.serialize()
            }
            fileView.setText(JSON.stringify(config, null, 2))
        }
    }
}

// config/AppearanceConfig.qml
JsonObject {
    property Rounding rounding: Rounding {}
    property Spacing spacing: Spacing {}

    component Rounding: JsonObject {
        property real scale: 1
        property int small: 8 * scale
        property int normal: 12 * scale
        property int large: 16 * scale

        function serialize(): object {
            return { scale, small, normal, large }
        }
    }

    component Spacing: JsonObject {
        property real scale: 1
        property int smaller: 4 * scale
        property int small: 8 * scale
        property int normal: 16 * scale
        property int large: 24 * scale
    }

    function serialize(): object {
        return {
            rounding: rounding.serialize(),
            spacing: spacing.serialize()
        }
    }
}

Convenience Alias

// config/Appearance.qml
pragma Singleton
import Quickshell

Singleton {
    // Shortens Config.appearance.* to Appearance.*
    property Rounding rounding: Config.appearance.rounding
    property Spacing spacing: Config.appearance.spacing
    property FontConfig font: Config.appearance.font
    property AnimConfig anim: Config.appearance.anim
    property real transparency: Config.appearance.transparency
}

Scale-Based Design Tokens

JsonObject {
    property real scale: 1

    // Computed from scale
    property int small: 12 * scale
    property int normal: 17 * scale
    property int large: 22 * scale

    // Changing scale automatically updates all derived values
}

State Management

PersistentProperties

// State survives hot reload
PersistentProperties {
    id: props
    reloadableId: "uniqueId"  // Must be unique
    property bool enabled: true
    property int count: 0
    property string lastAction: ""
}

Per-Screen State

// services/Visibilities.qml
pragma Singleton

Singleton {
    id: root
    property var screens: new Map()

    function load(screen, visibilities): void {
        screens.set(Hypr.monitorFor(screen), visibilities)
    }

    function getForActive(): PersistentProperties {
        return screens.get(Hypr.focusedMonitor)
    }
}

File Persistence

// Notifications persistence
Timer {
    id: saveTimer
    interval: 1000  // 1 second debounce
    onTriggered: {
        const data = list.map(n => n.serialize())
        fileView.setText(JSON.stringify(data, null, 2))
    }
}

// Update timer when list changes
onListChanged: saveTimer.restart()

Reference Counting

// services/SystemUsage.qml
Singleton {
    id: root
    property int refCount: 0

    // Only poll when someone needs data
    Timer {
        running: root.refCount > 0
        interval: 3000
        onTriggered: updateStats()
    }
}

// Component that needs stats
Ref { service: SystemUsage }  // Increments refCount

C++ Plugin Integration

Plugin Structure

# CMakeLists.txt
qt_add_qml_module(myplugin
    URI Caelestia
    VERSION 1.0
    SOURCES
        src/utils.cpp
        src/requests.cpp
    QML_FILES
        MyComponent.qml
)

QML Singleton

// src/utils.h
class CUtils : public QObject {
    Q_OBJECT
    QML_SINGLETON

public:
    Q_INVOKABLE void saveItem(QQuickItem* item, const QString& path);
    Q_INVOKABLE QString readFile(const QString& path);
};

QML Element

// src/appdb.h
class AppDb : public QObject {
    Q_OBJECT
    QML_ELEMENT

public:
    Q_INVOKABLE void recordLaunch(const QString& appId);
    Q_INVOKABLE QList<AppEntry> getRecent(int limit);
};

When to Use C++

Common Idioms

Debounce/Throttle

// Debounce config saves
Timer {
    id: saveTimer
    interval: 500
    onTriggered: saveConfig()
}

onConfigChanged: saveTimer.restart()  // Restart cancels previous

// Rate limit DDC brightness writes
Timer {
    id: ddcTimer
    interval: 500
    onTriggered: writeBrightness()
}

Toast Notifications

import Caelestia

Toaster.toast(
    "Volume Changed",           // Title
    "Volume set to 50%",        // Message
    "volume_up",                // Icon
    "info"                      // Type: info/success/warning/error
)

// Guarded by config
if (Config.utilities.toasts.volume) {
    Toaster.toast(...)
}

Default Property Alias (Slots)

// components/Card.qml
StyledRect {
    default property alias content: contentColumn.data

    ColumnLayout {
        id: contentColumn
        // Children added here via default property
    }
}

// Usage
Card {
    StyledText { text: "Title" }
    StyledText { text: "Content" }
}

Inline Components

// Define types inline
component ItemData: QtObject {
    required property string name
    required property int value
    property bool active: true
}

ListModel {
    ListElement {
        item: ItemData { name: "A"; value: 1 }
    }
}

i18n

StyledText {
    text: qsTr("Hello, World!")
}

StyledText {
    text: qsTr("Volume: %1%").arg(Math.round(volume * 100))
}

XDG Paths

// utils/Paths.qml
pragma Singleton

Singleton {
    readonly property string home: Qt.platform.os === "linux"
        ? Qt.environment.HOME
        : Qt.environment.USERPROFILE

    readonly property string data: Qt.environment.XDG_DATA_HOME
        ?? `${home}/.local/share`

    readonly property string config: Qt.environment.XDG_CONFIG_HOME
        ?? `${home}/.config`

    readonly property string cache: Qt.environment.XDG_CACHE_HOME
        ?? `${home}/.cache`

    readonly property string state: Qt.environment.XDG_STATE_HOME
        ?? `${home}/.local/state`

    function absolutePath(path: string): string {
        if (path.startsWith("~/")) return home + path.slice(1)
        if (path.startsWith("$HOME/")) return home + path.slice(5)
        return path
    }
}

Anti-Patterns to Avoid

❌ Don't hardcode colors/sizes

// BAD
color: "#1a1a1a"
font.pixelSize: 16

// GOOD
color: Colours.palette.m3surface
font.pixelSize: Appearance.font.size.normal

❌ Don't create multiple FileView for same file

// BAD - Each FileView watches separately
FileView { path: "/proc/stat" }
FileView { path: "/proc/stat" }

// GOOD - Centralize in service
// services/SystemUsage.qml has single FileView

❌ Don't poll when not needed

// BAD - Always polling
Timer { running: true; interval: 1000 }

// GOOD - Only when visible/needed
Timer { running: refCount > 0 }

❌ Don't forget persistent IDs

// BAD - State lost on reload
PersistentProperties { property bool enabled }

// GOOD - State survives reload
PersistentProperties {
    reloadableId: "featureName"
    property bool enabled
}

Debugging & Diagnostics

LSP Diagnostics

Check QML files for errors using the OpenCode LSP diagnostics command:

opencode debug lsp diagnostics <file.qml>

Use this after editing QML files to catch type errors, missing imports, unresolved properties, and other issues before reloading the shell. <file.qml> must be an absolute path.

QML Language Server (qmlls) Caveats

The QML language server has known limitations to be aware of:

• Broken when file is malformed: qmlls does not work well when a file is not correctly structured. Completions and lints won't work unless braces are closed correctly and the file is syntactically valid.
• No Quickshell type docs: The LSP cannot provide any documentation for Quickshell-specific types.
• PanelWindow unresolved: PanelWindow in particular cannot be resolved by qmlls, so diagnostics referencing it may be false positives.

To enable qmlls support, create an empty .qmlls.ini file next to shell.qml. Quickshell will replace it with a managed configuration. This file should be gitignored as its content is machine-specific.

Keep these caveats in mind when interpreting diagnostics -- some errors (especially around Quickshell-specific types like PanelWindow, ShellRoot, Singleton, Variants, etc.) may be false positives from the language server rather than actual bugs.

Resources

• Quickshell Documentation
• Material Design 3
• QML Best Practices