0.5.0: Added toolbar with scene picker

Editor/Toolbar/ToolbarDrawer.cs

@@ -0,0 +1,78 @@
+using Game.NavigationTool.Editor.Toolbar;
+using UnityEditor;
+using UnityEngine;
+
+namespace Game.NavigationTool.Editor
+{
+    [InitializeOnLoad]
+    internal static class ToolbarDrawer
+    {
+        private static bool IS_INITIALIZED;
+        private static IToolbarDrawer[] DRAWERS;
+        private static Styles styles;
+        
+        static ToolbarDrawer()
+        {
+            EditorApplication.update -= OnEditorUpdate;
+            EditorApplication.update += OnEditorUpdate;
+        }
+        
+        private static void OnEditorUpdate()
+        {
+            if (!IS_INITIALIZED)
+            {
+                styles = new Styles();
+                DRAWERS = ToolbarUtility.GetAllDrawers();
+                ToolbarUtility.AddGuiListener(OnGUI);
+                IS_INITIALIZED = true;
+            }
+
+            for (var i = 0; i < DRAWERS.Length; i++)
+            {
+                DRAWERS[i].Update();
+            }
+        }
+
+        private static void OnGUI()
+        {
+            const float Y = 5.0f;
+            const float SPACING = 8.0f;
+            const float HEIGHT = 22.0f;
+            const float PLAY_BUTTON_EXTENT = 48.0f;
+            
+            if (DRAWERS == null)
+                return;
+            
+            styles.Initialize(GUI.skin);
+            float xLeft = EditorGUIUtility.currentViewWidth * 0.5f - PLAY_BUTTON_EXTENT;
+            float xRight = EditorGUIUtility.currentViewWidth * 0.5f + PLAY_BUTTON_EXTENT;
+
+            for (var i = 0; i < DRAWERS.Length; i++)
+            {
+                IToolbarDrawer drawer = DRAWERS[i];
+                
+                if (!drawer.Visible)
+                    continue;
+
+                GUI.enabled = drawer.Enabled;
+                float width = drawer.CalculateWidth();
+                Rect rect;
+
+                if (drawer.Placement == EToolbarPlacement.Left)
+                {
+                    rect = new Rect(xLeft - width, Y, width, HEIGHT);
+                    xLeft -= width + SPACING;
+                }
+                else
+                {
+                    rect = new Rect(xRight, Y, width, HEIGHT);
+                    xRight += width + SPACING;
+                }
+
+                drawer.Draw(rect, styles);
+            }
+            
+            GUI.enabled = true;
+        }
+    }
+}