Gives the gas analyzer visual clues that it's open (#2110)

* Gives the gas analyzer visual clues that it's open

* Read Visualizer states from yaml

Content.Client/GameObjects/Components/Atmos/GasAnalyzerVisualizer.cs

@@ -0,0 +1,52 @@
+using Content.Shared.GameObjects.Components.Atmos;
+using Robust.Client.GameObjects;
+using Robust.Client.Interfaces.GameObjects.Components;
+using Robust.Shared.Utility;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Client.GameObjects.Components.Atmos
+{
+    public class GasAnalyzerVisualizer : AppearanceVisualizer
+    {
+        private string _stateOff;
+        private string _stateWorking;
+
+        public override void LoadData(YamlMappingNode node)
+        {
+            base.LoadData(node);
+
+            _stateOff = node.GetNode("state_off").AsString();
+            _stateWorking = node.GetNode("state_working").AsString();
+        }
+
+        public override void OnChangeData(AppearanceComponent component)
+        {
+            base.OnChangeData(component);
+
+            if (component.Deleted)
+            {
+                return;
+            }
+
+            if (!component.Owner.TryGetComponent(out ISpriteComponent sprite))
+            {
+                return;
+            }
+
+            if (component.TryGetData(GasAnalyzerVisuals.VisualState, out GasAnalyzerVisualState visualState))
+            {
+                switch (visualState)
+                {
+                    case GasAnalyzerVisualState.Off:
+                        sprite.LayerSetState(0, _stateOff);
+                        break;
+                    case GasAnalyzerVisualState.Working:
+                        sprite.LayerSetState(0, _stateWorking);
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }
+    }
+}