add volume and brightness control

services/Audio.qml

@@ -0,0 +1,59 @@
+pragma Singleton
+
+import Quickshell
+import Quickshell.Services.Pipewire
+import qs.config
+
+// The default audio sink. Quickshell talks to pipewire directly, so there is no
+// wpctl or pactl to shell out to and no polling: the properties below change as
+// the graph does, whoever moved them.
+//
+// Everything is expressed against the default sink rather than a remembered
+// one, so switching outputs — plugging in a headset, say — moves the panel with
+// the sound.
+Singleton {
+    id: root
+
+    readonly property PwNode sink: Pipewire.defaultAudioSink
+
+    // Pipewire objects only carry live properties while something is tracking
+    // them, so `audio` is null until the tracker below binds the node.
+    readonly property bool available: Config.showVolume && root.sink !== null && root.sink.ready && root.sink.audio !== null
+
+    // 0-1 for the usable range, though pipewire allows more and another client
+    // may well have set more. Reported as-is; the slider is what clamps.
+    readonly property real volume: root.available ? root.sink.audio.volume : 0
+    readonly property bool muted: root.available ? root.sink.audio.muted : false
+
+    function setVolume(value: real): void {
+        if (!root.available)
+            return;
+
+        root.sink.audio.volume = Math.max(0, Math.min(1, value));
+    }
+
+    // Raising the volume from silence unmutes: a volume key that appears to do
+    // nothing is worse than one that does slightly more than it said.
+    function step(delta: real): void {
+        if (!root.available)
+            return;
+
+        if (delta > 0 && root.muted)
+            root.setMuted(false);
+
+        root.setVolume(root.volume + delta);
+    }
+
+    function setMuted(muted: bool): void {
+        if (root.available)
+            root.sink.audio.muted = muted;
+    }
+
+    function toggleMute(): void {
+        root.setMuted(!root.muted);
+    }
+
+    PwObjectTracker {
+        objects: root.sink ? [root.sink] : []
+    }
+}