mixer: add example

mixer/shell.qml

@@ -0,0 +1,49 @@
+import QtQuick
+import QtQuick.Controls
+import QtQuick.Layouts
+import Quickshell
+import Quickshell.Services.Pipewire
+
+ShellRoot {
+	FloatingWindow {
+		// match the system theme background color
+		color: contentItem.palette.active.window
+
+		ScrollView {
+			anchors.fill: parent
+			contentWidth: availableWidth
+
+			ColumnLayout {
+				anchors.fill: parent
+				anchors.margins: 10
+
+				// get a list of nodes that output to the default sink
+				PwNodeLinkTracker {
+					id: linkTracker
+					node: Pipewire.defaultAudioSink
+				}
+
+				MixerEntry {
+					node: Pipewire.defaultAudioSink
+				}
+
+				Rectangle {
+					Layout.fillWidth: true
+					color: palette.active.text
+					implicitHeight: 1
+				}
+
+				Repeater {
+					model: linkTracker.linkGroups
+
+					MixerEntry {
+						required property PwLinkGroup modelData
+						// Each link group contains a source and a target.
+						// Since the target is the default sink, we want the source.
+						node: modelData.source
+					}
+				}
+			}
+		}
+	}
+}