From fc029b018ef7f4452d8f4f0d3bd6103778599912 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Fri, 8 Mar 2024 14:56:34 +0100
Subject: [PATCH] Fix UI size changes when saving scenes or prefabs in Editor
 with different layout

---
 Source/Editor/Modules/SceneModule.cs         | 42 ++++++++++++++++++++
 Source/Editor/Windows/Assets/PrefabWindow.cs |  6 +++
 2 files changed, 48 insertions(+)

diff --git a/Source/Editor/Modules/SceneModule.cs b/Source/Editor/Modules/SceneModule.cs
index 302d1e02a..9aae0b72f 100644
--- a/Source/Editor/Modules/SceneModule.cs
+++ b/Source/Editor/Modules/SceneModule.cs
@@ -6,6 +6,7 @@ using System.IO;
 using FlaxEditor.SceneGraph;
 using FlaxEditor.SceneGraph.Actors;
 using FlaxEngine;
+using FlaxEngine.GUI;
 using Object = FlaxEngine.Object;
 
 namespace FlaxEditor.Modules
@@ -454,6 +455,41 @@ namespace FlaxEditor.Modules
             Profiler.EndEvent();
         }
 
+        private Dictionary<ContainerControl, Float2> _uiRootSizes;
+
+        internal void OnSaveStart(ContainerControl uiRoot)
+        {
+            // Force viewport UI to have fixed size during scene/prefabs saving to result in stable data (less mess in version control diffs)
+            if (_uiRootSizes == null)
+                _uiRootSizes = new Dictionary<ContainerControl, Float2>();
+            _uiRootSizes[uiRoot] = uiRoot.Size;
+            uiRoot.Size = new Float2(1920, 1080);
+        }
+
+        internal void OnSaveEnd(ContainerControl uiRoot)
+        {
+            // Restore cached size of the UI root container
+            if (_uiRootSizes != null && _uiRootSizes.Remove(uiRoot, out var size))
+            {
+                uiRoot.Size = size;
+            }
+        }
+
+        private void OnSceneSaving(Scene scene, Guid sceneId)
+        {
+            OnSaveStart(RootControl.GameRoot);
+        }
+        
+        private void OnSceneSaved(Scene scene, Guid sceneId)
+        {
+            OnSaveEnd(RootControl.GameRoot);
+        }
+        
+        private void OnSceneSaveError(Scene scene, Guid sceneId)
+        {
+            OnSaveEnd(RootControl.GameRoot);
+        }
+
         private void OnSceneLoaded(Scene scene, Guid sceneId)
         {
             var startTime = DateTime.UtcNow;
@@ -659,6 +695,9 @@ namespace FlaxEditor.Modules
             Root = new ScenesRootNode();
 
             // Bind events
+            Level.SceneSaving += OnSceneSaving;
+            Level.SceneSaved += OnSceneSaved;
+            Level.SceneSaveError += OnSceneSaveError;
             Level.SceneLoaded += OnSceneLoaded;
             Level.SceneUnloading += OnSceneUnloading;
             Level.ActorSpawned += OnActorSpawned;
@@ -673,6 +712,9 @@ namespace FlaxEditor.Modules
         public override void OnExit()
         {
             // Unbind events
+            Level.SceneSaving -= OnSceneSaving;
+            Level.SceneSaved -= OnSceneSaved;
+            Level.SceneSaveError -= OnSceneSaveError;
             Level.SceneLoaded -= OnSceneLoaded;
             Level.SceneUnloading -= OnSceneUnloading;
             Level.ActorSpawned -= OnActorSpawned;
diff --git a/Source/Editor/Windows/Assets/PrefabWindow.cs b/Source/Editor/Windows/Assets/PrefabWindow.cs
index 5aa1486ee..2e3e700a2 100644
--- a/Source/Editor/Windows/Assets/PrefabWindow.cs
+++ b/Source/Editor/Windows/Assets/PrefabWindow.cs
@@ -355,6 +355,8 @@ namespace FlaxEditor.Windows.Assets
 
             try
             {
+                Editor.Scene.OnSaveStart(_viewport);
+
                 // Simply update changes
                 Editor.Prefabs.ApplyAll(_viewport.Instance);
 
@@ -371,6 +373,10 @@ namespace FlaxEditor.Windows.Assets
 
                 throw;
             }
+            finally
+            {
+                Editor.Scene.OnSaveEnd(_viewport);
+            }
         }
 
         /// <inheritdoc />