Set antiAliasing.

Editor/UIWidgetsPanelEditor.cs

         public override void OnInspectorGUI() {
             base.OnInspectorGUI();
             var pixelRatioProperty = this.serializedObject.FindProperty("devicePixelRatioOverride");
+            var antiAliasingProperty = this.serializedObject.FindProperty("antiAliasingOverride");
+            EditorGUILayout.PropertyField(antiAliasingProperty);
             this.serializedObject.ApplyModifiedProperties();
         }
     }

Runtime/editor/editor_window.cs

         protected override float queryDevicePixelRatio() {
             return EditorGUIUtility.pixelsPerPoint;
         }
+        
+        protected override int queryAntiAliasing() {
+            return 4;
+        }
 
         protected override Vector2 queryWindowSize() {
             return this.editorWindow.position.size;
 
         public void OnEnable() {
             this._devicePixelRatio = this.queryDevicePixelRatio();
+            this._antiAliasing = this.queryAntiAliasing();
             var size = this.queryWindowSize();
             this._lastWindowWidth = size.x;
             this._lastWindowHeight = size.y;
         }
 
         protected abstract float queryDevicePixelRatio();
+        protected abstract int queryAntiAliasing();
         protected abstract Vector2 queryWindowSize();
 
         protected virtual Surface createSurface() {

Runtime/editor/surface.cs

                 autoGenerateMips = false,
             };
 
-            if (QualitySettings.antiAliasing != 0) {
-                desc.msaaSamples = QualitySettings.antiAliasing;
+            if (Window.instance.antiAliasing != 0) {
+                desc.msaaSamples = Window.instance.antiAliasing;
             }
 
             this._renderTexture = new RenderTexture(desc);

Runtime/engine/UIWidgetsPanel.cs

         protected override float queryDevicePixelRatio() {
             return this._uiWidgetsPanel.devicePixelRatio;
         }
+        
+        protected override int queryAntiAliasing() {
+            return this._uiWidgetsPanel.antiAliasing;
+        }
 
         protected override Vector2 queryWindowSize() {
             var rect = this._uiWidgetsPanel.rectTransform.rect;
         static Event _repaintEvent;
 
         [SerializeField] protected float devicePixelRatioOverride;
+        [SerializeField] protected int antiAliasingOverride = 4;
         WindowAdapter _windowAdapter;
         Texture _texture;
         Vector2 _lastMouseMove;
                 return this.devicePixelRatioOverride > 0
                     ? this.devicePixelRatioOverride
                     : this._displayMetrics.devicePixelRatio;
+            }
+        }
+        
+        public int antiAliasing {
+            get {
+                return this.antiAliasingOverride >= 0 ? this.antiAliasingOverride : 4;
             }
         }
 

Runtime/flow/raster_cache.cs

                 autoGenerateMips = false,
             };
 
-            if (QualitySettings.antiAliasing != 0) {
-                desc.msaaSamples = QualitySettings.antiAliasing;
+            if (Window.instance.antiAliasing != 0) {
+                desc.msaaSamples = Window.instance.antiAliasing;
             }
 
             var renderTexture = new RenderTexture(desc);

Runtime/ui/painting/canvas_impl.cs

                             autoGenerateMips = false,
                         };
                 
-                        if (QualitySettings.antiAliasing != 0) {
-                            desc.msaaSamples = QualitySettings.antiAliasing;
+                        if (Window.instance.antiAliasing != 0) {
+                            desc.msaaSamples = Window.instance.antiAliasing;
                         }
                 
                         cmdBuf.GetTemporaryRT(subLayer.rtID, desc, subLayer.filterMode);

Runtime/ui/window.cs

         }
 
         protected float _devicePixelRatio = 1.0f;
+        
+        public int antiAliasing {
+            get { return this._antiAliasing; }
+        }
+
+        protected int _antiAliasing = 4;
 
         public Size physicalSize {
             get { return this._physicalSize; }

Tests/Editor/CanvasAndLayers.cs

                     autoGenerateMips = false,
                 };
 
-                if (QualitySettings.antiAliasing != 0) {
-                    desc.msaaSamples = QualitySettings.antiAliasing;
+                if (Window.instance.antiAliasing != 0) {
+                    desc.msaaSamples = Window.instance.antiAliasing;
                 }
 
                 this._renderTexture = RenderTexture.GetTemporary(desc);