blur: add probe to check compositor for ext-bg-effect

quickshell/Services/BlurService.qml

@@ -3,13 +3,16 @@ pragma ComponentBehavior: Bound
 
 import QtQuick
 import Quickshell
+import Quickshell.Io
 import Quickshell.Wayland // ! Import is needed despite what qmlls says
 import qs.Common
 
 Singleton {
     id: root
 
-    property bool available: false
+    property bool quickshellSupported: false
+    property bool compositorSupported: false
+    property bool available: quickshellSupported && compositorSupported
     readonly property bool enabled: available && (SettingsData.blurEnabled ?? false)
 
     readonly property color borderColor: {
@@ -72,6 +75,27 @@ Singleton {
         region.destroy();
     }
 
+    Process {
+        id: blurProbe
+        running: false
+        command: ["dms", "blur", "check"]
+
+        stdout: StdioCollector {
+            onStreamFinished: {
+                root.compositorSupported = text.trim() === "supported";
+                if (root.compositorSupported)
+                    console.info("BlurService: Compositor supports ext-background-effect-v1");
+                else
+                    console.info("BlurService: Compositor does not support ext-background-effect-v1");
+            }
+        }
+
+        onExited: exitCode => {
+            if (exitCode !== 0)
+                console.warn("BlurService: blur probe failed with code:", exitCode);
+        }
+    }
+
     Component.onCompleted: {
         try {
             const test = Qt.createQmlObject(`
@@ -79,8 +103,9 @@ Singleton {
                 Region { radius: 0 }
             `, root, "BlurAvailabilityTest");
             test.destroy();
-            available = true;
-            console.info("BlurService: Initialized with blur support");
+            quickshellSupported = true;
+            console.info("BlurService: Quickshell blur support available");
+            blurProbe.running = true;
         } catch (e) {
             console.info("BlurService: BackgroundEffect not available - blur disabled. Requires a newer version of Quickshell.");
         }