Internals: Split some code out of NewFrame() into an Initialize() function.

imgui.cpp

@@ -2125,16 +2125,9 @@ void ImGui::NewFrame()
     IM_ASSERT(g.Style.CurveTessellationTol > 0.0f);  // Invalid style setting
     IM_ASSERT(g.Style.Alpha >= 0.0f && g.Style.Alpha <= 1.0f);  // Invalid style setting. Alpha cannot be negative (allows us to avoid a few clamps in color computations)
 
+    // Initialize on first frame
     if (!g.Initialized)
-    {
-        // Initialize on first frame
-        g.LogClipboard = (ImGuiTextBuffer*)ImGui::MemAlloc(sizeof(ImGuiTextBuffer));
-        IM_PLACEMENT_NEW(g.LogClipboard) ImGuiTextBuffer();
-
-        IM_ASSERT(g.Settings.empty());
-        LoadIniSettingsFromDisk(g.IO.IniFilename);
-        g.Initialized = true;
-    }
+        ImGui::Initialize();
 
     SetCurrentFont(GetDefaultFont());
     IM_ASSERT(g.Font->IsLoaded());
@@ -2350,7 +2343,18 @@ void ImGui::NewFrame()
     ImGui::Begin("Debug");
 }
 
-// NB: behavior of ImGui after Shutdown() is not tested/guaranteed at the moment. This function is merely here to free heap allocations.
+void ImGui::Initialize()
+{
+    ImGuiContext& g = *GImGui;
+    g.LogClipboard = (ImGuiTextBuffer*)ImGui::MemAlloc(sizeof(ImGuiTextBuffer));
+    IM_PLACEMENT_NEW(g.LogClipboard) ImGuiTextBuffer();
+
+    IM_ASSERT(g.Settings.empty());
+    LoadIniSettingsFromDisk(g.IO.IniFilename);
+    g.Initialized = true;
+}
+
+// This function is merely here to free heap allocations.
 void ImGui::Shutdown()
 {
     ImGuiContext& g = *GImGui;
@@ -2359,7 +2363,7 @@ void ImGui::Shutdown()
     if (g.IO.Fonts) // Testing for NULL to allow user to NULLify in case of running Shutdown() on multiple contexts. Bit hacky.
         g.IO.Fonts->Clear();
 
-    // Cleanup of other data are conditional on actually having used ImGui.
+    // Cleanup of other data are conditional on actually having initialize ImGui.
     if (!g.Initialized)
         return;
 

imgui_internal.h

@@ -741,6 +741,7 @@ namespace ImGui
     IMGUI_API ImGuiWindow*  FindWindowByName(const char* name);
     IMGUI_API void          FocusWindow(ImGuiWindow* window);
 
+    IMGUI_API void          Initialize();
     IMGUI_API void          EndFrame();                 // Ends the ImGui frame. Automatically called by Render()! you most likely don't need to ever call that yourself directly. If you don't need to render you can call EndFrame() but you'll have wasted CPU already. If you don't need to render, don't create any windows instead!
 
     IMGUI_API void          SetActiveID(ImGuiID id, ImGuiWindow* window);