Add focused window controls to top bar

Introduces a new `WindowControls` component in the desktop top bar with minimize, maximize/restore, and close actions for the focused window. `WindowService` now exposes focused-window presence/maximized state plus focused-window convenience actions to support this UI.

Also extends Nebula UI with a reusable `NebulaToolTip`, keyboard/pressed-state support in `NebulaIconButton`, new window-control glyphs in `NebulaIcon`, and theme tokens for pressed/danger hover states, with CMake and README updates to register/document the new components.

packages/nebula-ui/CMakeLists.txt

@@ -16,6 +16,7 @@ set(NEBULA_UI_QML_FILES
     NebulaCard.qml
     NebulaIconButton.qml
     NebulaTextField.qml
+    NebulaToolTip.qml
     FocusFrame.qml
     NebulaIcon.qml
 )

packages/nebula-ui/README.md

@@ -11,7 +11,7 @@ import Nebula.UI
 This module contains reusable visual language only:
 
 - colour, spacing, type, and motion tokens (`Theme`)
-- generic controls (`NebulaButton`, `NebulaCard`, `NebulaIconButton`, `NebulaTextField`)
+- generic controls (`NebulaButton`, `NebulaCard`, `NebulaIconButton`, `NebulaTextField`, `NebulaToolTip`)
 - focus treatment (`FocusFrame`)
 - compact vector icons (`NebulaIcon`)
 

packages/nebula-ui/qml/Nebula/UI/NebulaIcon.qml

@@ -82,6 +82,18 @@ Item {
         case "application":
             paintApplication(ctx)
             break
+        case "minimize":
+            paintMinimize(ctx)
+            break
+        case "maximize":
+            paintMaximize(ctx)
+            break
+        case "restore":
+            paintRestore(ctx)
+            break
+        case "close":
+            paintClose(ctx)
+            break
         default:
             paintApplication(ctx)
             break
@@ -192,6 +204,41 @@ Item {
         ctx.stroke()
     }
 
+    function paintMinimize(ctx) {
+        ctx.lineWidth = 1.7
+        ctx.beginPath()
+        ctx.moveTo(6.4, 16.2)
+        ctx.lineTo(17.6, 16.2)
+        ctx.stroke()
+    }
+
+    function paintMaximize(ctx) {
+        ctx.lineWidth = 1.5
+        ctx.beginPath()
+        roundedRect(ctx, 6.2, 6.2, 11.6, 11.6, 2)
+        ctx.stroke()
+    }
+
+    function paintRestore(ctx) {
+        ctx.lineWidth = 1.45
+        ctx.beginPath()
+        roundedRect(ctx, 8.6, 5.6, 9.4, 9.4, 1.7)
+        ctx.stroke()
+        ctx.beginPath()
+        roundedRect(ctx, 5.6, 8.6, 9.4, 9.4, 1.7)
+        ctx.stroke()
+    }
+
+    function paintClose(ctx) {
+        ctx.lineWidth = 1.7
+        ctx.beginPath()
+        ctx.moveTo(7.3, 7.3)
+        ctx.lineTo(16.7, 16.7)
+        ctx.moveTo(16.7, 7.3)
+        ctx.lineTo(7.3, 16.7)
+        ctx.stroke()
+    }
+
     function paintApplication(ctx) {
         ctx.lineWidth = 1.5
         ctx.beginPath()

packages/nebula-ui/qml/Nebula/UI/NebulaIconButton.qml

@@ -7,6 +7,7 @@ Item {
     property bool active: false
     property bool danger: false
     readonly property bool hovered: hover.containsMouse
+    readonly property bool pressed: hover.pressed
     readonly property color iconColor: {
         if (danger && hovered)
             return Theme.danger
@@ -23,16 +24,32 @@ Item {
 
     implicitWidth: Theme.controlHeight
     implicitHeight: Theme.controlHeight
+    activeFocusOnTab: true
     Accessible.role: Accessible.Button
     Accessible.name: root.label
     Accessible.onPressAction: root.clicked()
 
+    Keys.onReturnPressed: {
+        event.accepted = true
+        root.clicked()
+    }
+    Keys.onSpacePressed: {
+        event.accepted = true
+        root.clicked()
+    }
+
     Rectangle {
         anchors.fill: parent
         radius: Theme.radiusSmall
         color: {
+            if (root.danger && hover.pressed)
+                return Theme.dangerSoftStrong
+            if (root.danger && hover.containsMouse)
+                return Theme.dangerSoft
             if (root.active)
                 return Theme.accentSoft
+            if (hover.pressed)
+                return Theme.pressedFill
             if (hover.containsMouse)
                 return Theme.hoverFill
             return "transparent"
@@ -63,4 +80,9 @@ Item {
     FocusFrame {
         radius: Theme.radiusSmall
     }
+
+    NebulaToolTip {
+        text: root.label
+        active: hover.containsMouse && !hover.pressed && root.label.length > 0
+    }
 }

packages/nebula-ui/qml/Nebula/UI/NebulaToolTip.qml

@@ -0,0 +1,98 @@
+import QtQuick
+import QtQuick.Window
+
+Item {
+    id: root
+
+    property string text: ""
+    property bool active: false
+    property int delay: 550
+    property int timeout: 4000
+
+    width: 0
+    height: 0
+    enabled: false
+    Accessible.ignored: true
+
+    Timer {
+        id: showTimer
+        interval: root.delay
+        repeat: false
+        onTriggered: root.open()
+    }
+
+    Timer {
+        id: hideTimer
+        interval: root.timeout
+        repeat: false
+        onTriggered: tip.visible = false
+    }
+
+    Window {
+        id: tip
+        flags: Qt.Popup | Qt.ToolTip | Qt.FramelessWindowHint | Qt.WindowDoesNotAcceptFocus
+        color: "transparent"
+        visible: false
+        width: Math.ceil(tipText.implicitWidth) + 16
+        height: Math.ceil(tipText.implicitHeight) + 10
+
+        Rectangle {
+            anchors.fill: parent
+            radius: Theme.radiusSmall
+            color: Theme.surfaceRaised
+            border.color: Theme.borderStrong
+            border.width: 1
+
+            Text {
+                id: tipText
+                anchors.centerIn: parent
+                text: root.text
+                color: Theme.textPrimary
+                font.family: Theme.fontFamily
+                font.pixelSize: Theme.fontSizeSmall
+            }
+        }
+    }
+
+    onActiveChanged: root.sync()
+    onTextChanged: {
+        if (tip.visible)
+            root.place()
+        else
+            root.sync()
+    }
+
+    function sync() {
+        if (root.active && root.text.length > 0) {
+            showTimer.restart()
+            return
+        }
+        showTimer.stop()
+        hideTimer.stop()
+        tip.visible = false
+    }
+
+    function open() {
+        if (!root.active || root.text.length === 0)
+            return
+        const host = root.parent
+        if (!host)
+            return
+        const win = host.Window.window
+        if (win)
+            tip.transientParent = win
+        root.place()
+        tip.visible = true
+        hideTimer.restart()
+    }
+
+    function place() {
+        const host = root.parent
+        if (!host)
+            return
+        const pos = host.mapToGlobal(host.width / 2, host.height + 6)
+        const screenWidth = Screen.width
+        tip.x = Math.round(Math.max(8, Math.min(pos.x - tip.width / 2, screenWidth - tip.width - 8)))
+        tip.y = Math.round(pos.y)
+    }
+}

packages/nebula-ui/qml/Nebula/UI/Theme.qml

@@ -26,6 +26,9 @@ QtObject {
     readonly property color focus: Qt.rgba(126 / 255, 160 / 255, 196 / 255, 0.55)
 
     readonly property color hoverFill: Qt.rgba(1, 1, 1, 0.06)
+    readonly property color pressedFill: Qt.rgba(1, 1, 1, 0.10)
+    readonly property color dangerSoft: Qt.rgba(201 / 255, 136 / 255, 136 / 255, 0.18)
+    readonly property color dangerSoftStrong: Qt.rgba(201 / 255, 136 / 255, 136 / 255, 0.28)
     readonly property color tileHover: Qt.rgba(1, 1, 1, 0.05)
     readonly property color iconWell: Qt.rgba(1, 1, 1, 0.05)
     readonly property color iconWellHighlight: Qt.rgba(1, 1, 1, 0.06)