backlight panel: flash on hotkey changes

modules/Backlight.qml

@@ -13,7 +13,21 @@ M.BarSection {
 
     property int percent: 0
     property bool _panelHovered: false
-    readonly property bool _showPanel: root._hovered || _panelHovered
+    property bool _osdActive: false
+    readonly property bool _showPanel: root._hovered || _panelHovered || _osdActive
+
+    onPercentChanged: if (percent > 0) _flashPanel()
+
+    function _flashPanel() {
+        _osdActive = true;
+        _osdTimer.restart();
+    }
+
+    Timer {
+        id: _osdTimer
+        interval: 1500
+        onTriggered: root._osdActive = false
+    }
 
     Process {
         id: adjProc

modules/Volume.qml

@@ -31,7 +31,36 @@ M.BarSection {
 
     property bool _expanded: false
     property bool _panelHovered: false
-    readonly property bool _showPanel: root._hovered || _panelHovered || _expanded
+    property bool _osdActive: false
+    readonly property bool _anyHover: root._hovered || _panelHovered
+    readonly property bool _showPanel: _anyHover || _expanded || _osdActive
+
+    onVolumeChanged: _flashPanel()
+    onMutedChanged: _flashPanel()
+
+    function _flashPanel() {
+        _osdActive = true;
+        _osdTimer.restart();
+    }
+
+    Timer {
+        id: _osdTimer
+        interval: 1500
+        onTriggered: root._osdActive = false
+    }
+
+    on_AnyHoverChanged: {
+        if (_anyHover)
+            _collapseTimer.stop();
+        else if (_expanded)
+            _collapseTimer.start();
+    }
+
+    Timer {
+        id: _collapseTimer
+        interval: 500
+        onTriggered: root._expanded = false
+    }
 
     M.BarIcon {
         icon: root._volumeIcon