Add display identification overlays

config/dot/quickshell/display-arrangement-harness.qml

@@ -3,8 +3,11 @@ import Quickshell.Io
 import QtQuick
 
 import qs.modules.settings
+import qs.services
 
 ShellRoot {
+    DisplayIdentify {}
+
     QtObject {
         id: fixtureService
 
@@ -71,5 +74,8 @@ ShellRoot {
                 name: record.name, x: record.x, y: record.y, primary: record.primary
             })));
         }
+
+        function identify(): void { Displays.identify(); }
+        function identifying(): bool { return Displays.identifying; }
     }
 }

config/dot/quickshell/modules/settings/DisplayArrangement.qml

@@ -279,7 +279,8 @@ Item {
             spacing: 8
 
             Text {
-                width: Math.max(0, parent.width - primaryButton.width - applyButton.width - 16)
+                width: Math.max(0, parent.width - identifyButton.width
+                    - primaryButton.width - applyButton.width - 24)
                 anchors.verticalCenter: parent.verticalCenter
                 text: root.width >= 600
                     ? "Drag to arrange · arrows move 10 px · Shift moves 100 px"
@@ -290,6 +291,13 @@ Item {
                 elide: Text.ElideRight
             }
 
+            SettingsButton {
+                id: identifyButton
+                text: "Identify"
+                enabled: root.interactionEnabled
+                onClicked: root.displayService.identify()
+            }
+
             SettingsButton {
                 id: primaryButton
                 text: "Make primary"

config/dot/quickshell/modules/settings/DisplayIdentify.qml

@@ -0,0 +1,85 @@
+import Quickshell
+import Quickshell.Wayland
+import QtQuick
+import qs.config
+import qs.services
+import qs.widgets
+
+Variants {
+    model: Quickshell.screens
+
+    PanelWindow {
+        id: win
+
+        property var modelData: null
+        readonly property string connector: win.modelData?.name ?? "Display"
+        readonly property int number: Math.max(1,
+            Displays.monitors.findIndex(monitor => monitor.name === win.connector) + 1)
+        readonly property string description: Displays.monitorNamed(win.connector)?.description ?? "Connected display"
+
+        screen: win.modelData
+        visible: Displays.identifying
+        implicitWidth: 260
+        implicitHeight: 172
+        color: "transparent"
+        exclusiveZone: 0
+        exclusionMode: ExclusionMode.Ignore
+        mask: Region {}
+
+        WlrLayershell.namespace: "qs-display-identify"
+        WlrLayershell.layer: WlrLayer.Overlay
+        WlrLayershell.keyboardFocus: WlrKeyboardFocus.None
+
+        Rectangle {
+            anchors.fill: parent
+            radius: Theme.popoverRadius
+            color: Theme.alpha(Theme.bgPopover, 0.96)
+            border.width: 1
+            border.color: Theme.alpha(Theme.fg, 0.14)
+
+            PrismEdge {
+                anchors.top: parent.top
+                anchors.left: parent.left
+                anchors.right: parent.right
+                inset: parent.radius
+            }
+
+            Column {
+                anchors.centerIn: parent
+                width: parent.width - 32
+                spacing: 4
+
+                Text {
+                    width: parent.width
+                    horizontalAlignment: Text.AlignHCenter
+                    text: String(win.number)
+                    color: Theme.fg
+                    font.family: Theme.fontFamily
+                    font.pixelSize: 68
+                    font.weight: Font.DemiBold
+                }
+
+                Text {
+                    width: parent.width
+                    horizontalAlignment: Text.AlignHCenter
+                    text: win.connector
+                    color: Theme.accentAlt
+                    font.family: Theme.fontFamily
+                    font.pixelSize: Theme.fontSizeLarge
+                    font.weight: Font.DemiBold
+                    elide: Text.ElideRight
+                }
+
+                Text {
+                    width: parent.width
+                    horizontalAlignment: Text.AlignHCenter
+                    text: win.description
+                    color: Theme.fgDim
+                    font.family: Theme.fontFamily
+                    font.pixelSize: Theme.fontSizeSmall
+                    elide: Text.ElideRight
+                }
+            }
+        }
+    }
+}

config/dot/quickshell/modules/settings/qmldir

@@ -43,6 +43,7 @@ ShortcutCapture 1.0 ShortcutCapture.qml
 ChoiceGrid 1.0 ChoiceGrid.qml
 DisplayModePicker 1.0 DisplayModePicker.qml
 DisplayArrangement 1.0 DisplayArrangement.qml
+DisplayIdentify 1.0 DisplayIdentify.qml
 WifiPanel 1.0 WifiPanel.qml
 BluetoothPanel 1.0 BluetoothPanel.qml
 PasswordField 1.0 PasswordField.qml

config/dot/quickshell/services/Displays.qml

@@ -43,6 +43,7 @@ Singleton {
     property int revertGeneration: -1
     property bool externalChangeBlocked: false
     property int secondsLeft: 0
+    property bool identifying: false
 
     readonly property bool awaitingConfirmation: root.pendingRequestedLayout !== null
     readonly property bool canConfirm: root.awaitingConfirmation
@@ -123,6 +124,11 @@ Singleton {
         return false;
     }
 
+    function identify(): void {
+        root.identifying = true;
+        identifyTimer.restart();
+    }
+
     function parse(text: string, generation: int): void {
         try {
             const raw = JSON.parse(text);
@@ -520,6 +526,13 @@ Singleton {
         root.lastError = "The previous display setting could not be verified. Open Displays and restore it manually.";
     }
 
+    Timer {
+        id: identifyTimer
+        interval: 3000
+        repeat: false
+        onTriggered: root.identifying = false
+    }
+
     Timer {
         id: verifyTimer
         property int attempts: 0

config/dot/quickshell/shell.qml

@@ -86,6 +86,8 @@ ShellRoot {
         Osd {}
     }
 
+    DisplayIdentify {}
+
     // ── Single-instance overlays ────────────────────────────────────────────
     // These are always constructed but only *visible* when ShellState says so.
     // They're cheap while hidden, and keeping them alive means opening the