From fcd98ee2bb557c8048c91749e03b8defed593b32 Mon Sep 17 00:00:00 2001
From: meli <57847713+ff-meli@users.noreply.github.com>
Date: Wed, 29 Apr 2020 17:13:05 -0700
Subject: [PATCH] Add ability for plugins to add ImGui fonts at runtime, though
 we should discourage this as much as possible.  Also sneak in an api-matching
 update to part of ImGuiScene, to make more things useable in SamplePlugin

---
 Dalamud/Interface/InterfaceManager.cs | 85 +++++++++++++++++++--------
 Dalamud/Interface/UiBuilder.cs        | 20 +++++++
 lib/ImGuiScene                        |  2 +-
 3 files changed, 81 insertions(+), 26 deletions(-)

diff --git a/Dalamud/Interface/InterfaceManager.cs b/Dalamud/Interface/InterfaceManager.cs
index 3d66d24d8..5fde5a051 100644
--- a/Dalamud/Interface/InterfaceManager.cs
+++ b/Dalamud/Interface/InterfaceManager.cs
@@ -54,11 +54,15 @@ namespace Dalamud.Interface
 
         public ImGuiIOPtr LastImGuiIoPtr;
 
+        public Action OnBuildFonts;
+        private bool isRebuildingFonts = false;
+
         /// <summary>
         /// This event gets called by a plugin UiBuilder when read
         /// </summary>
         public event RawDX11Scene.BuildUIDelegate OnDraw;
 
+
         public InterfaceManager(Dalamud dalamud, SigScanner scanner)
         {
             this.dalamud = dalamud;
@@ -200,7 +204,18 @@ namespace Dalamud.Interface
             return null;
         }
 
-        private unsafe IntPtr PresentDetour(IntPtr swapChain, uint syncInterval, uint presentFlags)
+        // Sets up a deferred invocation of font rebuilding, before the next render frame
+        public void RebuildFonts()
+        {
+            // don't invoke this multiple times per frame, in case multiple plugins call it
+            if (!this.isRebuildingFonts)
+            {
+                this.isRebuildingFonts = true;
+                this.scene.OnNewRenderFrame += RebuildFontsInternal;
+            }
+        }
+
+        private IntPtr PresentDetour(IntPtr swapChain, uint syncInterval, uint presentFlags)
         {
             if (this.scene == null)
             {
@@ -209,30 +224,7 @@ namespace Dalamud.Interface
                 this.scene.OnBuildUI += Display;
                 this.scene.OnNewInputFrame += OnNewInputFrame;
 
-                ImFontConfigPtr fontConfig = ImGuiNative.ImFontConfig_ImFontConfig();
-                fontConfig.MergeMode = true;
-                fontConfig.PixelSnapH = true;
-
-                var fontPathJp = Path.Combine(this.dalamud.StartInfo.WorkingDirectory, "UIRes", "NotoSansCJKjp-Medium.otf");
-                ImGui.GetIO().Fonts.AddFontFromFileTTF(fontPathJp, 17.0f, null, ImGui.GetIO().Fonts.GetGlyphRangesJapanese());
-
-                var fontPathGame = Path.Combine(this.dalamud.StartInfo.WorkingDirectory, "UIRes", "gamesym.ttf");
-                Log.Verbose(fontPathGame);
-
-                var rangeHandle = GCHandle.Alloc(new ushort[]
-                {
-                    0xE020,
-                    0xE0DB,
-                    0
-                }, GCHandleType.Pinned);
-
-
-                ImGui.GetIO().Fonts.AddFontFromFileTTF(fontPathGame, 17.0f, fontConfig, rangeHandle.AddrOfPinnedObject());
-
-                ImGui.GetIO().Fonts.Build();
-
-                fontConfig.Destroy();
-                rangeHandle.Free();
+                SetupFonts();
 
                 ImGui.GetStyle().GrabRounding = 3f;
                 ImGui.GetStyle().FrameRounding = 4f;
@@ -268,6 +260,49 @@ namespace Dalamud.Interface
             return this.presentHook.Original(swapChain, syncInterval, presentFlags);
         }
 
+        private unsafe void SetupFonts()
+        {
+            ImGui.GetIO().Fonts.Clear();
+
+            ImFontConfigPtr fontConfig = ImGuiNative.ImFontConfig_ImFontConfig();
+            fontConfig.MergeMode = true;
+            fontConfig.PixelSnapH = true;
+
+            var fontPathJp = Path.Combine(this.dalamud.StartInfo.WorkingDirectory, "UIRes", "NotoSansCJKjp-Medium.otf");
+            ImGui.GetIO().Fonts.AddFontFromFileTTF(fontPathJp, 17.0f, null, ImGui.GetIO().Fonts.GetGlyphRangesJapanese());
+
+            var fontPathGame = Path.Combine(this.dalamud.StartInfo.WorkingDirectory, "UIRes", "gamesym.ttf");
+            Log.Verbose(fontPathGame);
+
+            var rangeHandle = GCHandle.Alloc(new ushort[]
+            {
+                0xE020,
+                0xE0DB,
+                0
+            }, GCHandleType.Pinned);
+
+
+            ImGui.GetIO().Fonts.AddFontFromFileTTF(fontPathGame, 17.0f, fontConfig, rangeHandle.AddrOfPinnedObject());
+
+            OnBuildFonts?.Invoke();
+
+            ImGui.GetIO().Fonts.Build();
+
+            fontConfig.Destroy();
+            rangeHandle.Free();
+        }
+
+        // This is intended to only be called as a handler attached to scene.OnNewRenderFrame
+        private void RebuildFontsInternal()
+        {
+            SetupFonts();
+
+            this.scene.OnNewRenderFrame -= RebuildFontsInternal;
+            this.scene.InvalidateFonts();
+
+            this.isRebuildingFonts = false;
+        }
+
         private IntPtr ResizeBuffersDetour(IntPtr swapChain, uint bufferCount, uint width, uint height, uint newFormat, uint swapChainFlags)
         {
             Log.Verbose($"Calling resizebuffers {bufferCount} {width} {height} {newFormat} {swapChainFlags}");
diff --git a/Dalamud/Interface/UiBuilder.cs b/Dalamud/Interface/UiBuilder.cs
index 31468e302..8b2d3f30a 100644
--- a/Dalamud/Interface/UiBuilder.cs
+++ b/Dalamud/Interface/UiBuilder.cs
@@ -70,6 +70,26 @@ namespace Dalamud.Interface
         public TextureWrap LoadImageRaw(byte[] imageData, int width, int height, int numChannels) =>
             this.interfaceManager.LoadImageRaw(imageData, width, height, numChannels);
 
+        /// <summary>
+        /// An event that is called any time ImGui fonts need to be rebuilt.<br/>
+        /// Any ImFontPtr objects that you store <strong>can be invalidated</strong> when fonts are rebuilt
+        /// (at any time), so you should both reload your custom fonts and restore those
+        /// pointers inside this handler.
+        /// </summary>
+        public Action OnBuildFonts
+        {
+            get { return this.interfaceManager.OnBuildFonts; }
+            set { this.interfaceManager.OnBuildFonts = value; }
+        }
+
+        /// <summary>
+        /// Call this to queue a rebuild of the font atlas.<br/>
+        /// This will invoke any <see cref="OnBuildFonts"/> handlers and ensure that any loaded fonts are
+        /// ready to be used on the next UI frame.
+        /// </summary>
+        public void RebuildFonts() =>
+            this.interfaceManager.RebuildFonts();
+
         /// <summary>
         /// Event that is fired when the plugin should open its configuration interface.
         /// </summary>
diff --git a/lib/ImGuiScene b/lib/ImGuiScene
index aaa037938..d5b9345dc 160000
--- a/lib/ImGuiScene
+++ b/lib/ImGuiScene
@@ -1 +1 @@
-Subproject commit aaa037938d6fe835a15542a3451d12108e3f83b6
+Subproject commit d5b9345dc1463d746b832843bd7c81b753d4e5b0