Internals: Added support for context hooks (for test engine or other extensions)

imgui.cpp

@@ -3310,6 +3310,24 @@ void ImGui::DestroyContext(ImGuiContext* ctx)
     IM_DELETE(ctx);
 }
 
+// No specific ordering/dependency support, will see as needed
+void ImGui::AddContextHook(ImGuiContext* ctx, const ImGuiContextHook* hook)
+{
+    ImGuiContext& g = *ctx;
+    IM_ASSERT(hook->Callback != NULL);
+    g.Hooks.push_back(*hook);
+}
+
+// Call context hooks (used by e.g. test engine)
+// We assume a small number of hooks so all stored in same array
+void ImGui::CallContextHooks(ImGuiContext* ctx, ImGuiContextHookType hook_type)
+{
+    ImGuiContext& g = *ctx;
+    for (int n = 0; n < g.Hooks.Size; n++)
+        if (g.Hooks[n].Type == hook_type)
+            g.Hooks[n].Callback(&g, &g.Hooks[n]);
+}
+
 ImGuiIO& ImGui::GetIO()
 {
     IM_ASSERT(GImGui != NULL && "No current context. Did you call ImGui::CreateContext() and ImGui::SetCurrentContext() ?");
@@ -3735,9 +3753,7 @@ void ImGui::NewFrame()
     IM_ASSERT(GImGui != NULL && "No current context. Did you call ImGui::CreateContext() and ImGui::SetCurrentContext() ?");
     ImGuiContext& g = *GImGui;
 
-#ifdef IMGUI_ENABLE_TEST_ENGINE
-    ImGuiTestEngineHook_PreNewFrame(&g);
-#endif
+    CallContextHooks(&g, ImGuiContextHookType_NewFramePre);
 
     // Check and assert for various common IO and Configuration mistakes
     ErrorCheckNewFrameSanityChecks();
@@ -3907,9 +3923,7 @@ void ImGui::NewFrame()
     Begin("Debug##Default");
     IM_ASSERT(g.CurrentWindow->IsFallbackWindow == true);
 
-#ifdef IMGUI_ENABLE_TEST_ENGINE
-    ImGuiTestEngineHook_PostNewFrame(&g);
-#endif
+    CallContextHooks(&g, ImGuiContextHookType_NewFramePost);
 }
 
 // [DEBUG] Item picker tool - start with DebugStartItemPicker() - useful to visually select an item and break into its call-stack.
@@ -3994,15 +4008,12 @@ void ImGui::Shutdown(ImGuiContext* context)
     if (g.SettingsLoaded && g.IO.IniFilename != NULL)
     {
         ImGuiContext* backup_context = GImGui;
-        SetCurrentContext(context);
+        SetCurrentContext(&g);
         SaveIniSettingsToDisk(g.IO.IniFilename);
         SetCurrentContext(backup_context);
     }
 
-    // Notify hooked test engine, if any
-#ifdef IMGUI_ENABLE_TEST_ENGINE
-    ImGuiTestEngineHook_Shutdown(context);
-#endif
+    CallContextHooks(&g, ImGuiContextHookType_Shutdown);
 
     // Clear everything else
     for (int i = 0; i < g.Windows.Size; i++)
@@ -4202,6 +4213,8 @@ void ImGui::EndFrame()
         return;
     IM_ASSERT(g.WithinFrameScope && "Forgot to call ImGui::NewFrame()?");
 
+    CallContextHooks(&g, ImGuiContextHookType_EndFramePre);
+
     ErrorCheckEndFrameSanityChecks();
 
     // Notify OS when our Input Method Editor cursor has moved (e.g. CJK inputs using Microsoft IME)
@@ -4268,6 +4281,8 @@ void ImGui::EndFrame()
     g.IO.MouseWheel = g.IO.MouseWheelH = 0.0f;
     g.IO.InputQueueCharacters.resize(0);
     memset(g.IO.NavInputs, 0, sizeof(g.IO.NavInputs));
+
+    CallContextHooks(&g, ImGuiContextHookType_EndFramePost);
 }
 
 void ImGui::Render()
@@ -4281,6 +4296,8 @@ void ImGui::Render()
     g.IO.MetricsRenderWindows = 0;
     g.DrawDataBuilder.Clear();
 
+    CallContextHooks(&g, ImGuiContextHookType_RenderPre);
+
     // Add background ImDrawList
     if (!g.BackgroundDrawList.VtxBuffer.empty())
         AddDrawListToDrawData(&g.DrawDataBuilder.Layers[0], &g.BackgroundDrawList);
@@ -4318,6 +4335,8 @@ void ImGui::Render()
     if (g.DrawData.CmdListsCount > 0 && g.IO.RenderDrawListsFn != NULL)
         g.IO.RenderDrawListsFn(&g.DrawData);
 #endif
+
+    CallContextHooks(&g, ImGuiContextHookType_RenderPost);
 }
 
 // Calculate text size. Text can be multi-line. Optionally ignore text after a ## marker.

imgui.h

@@ -60,7 +60,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.79"
-#define IMGUI_VERSION_NUM           17900
+#define IMGUI_VERSION_NUM           17901
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 
 // Define attributes of all API symbols declarations (e.g. for DLL under Windows)

imgui_internal.h

@@ -19,16 +19,17 @@ Index of this file:
 // [SECTION] ImDrawList support
 // [SECTION] Widgets support: flags, enums, data structures
 // [SECTION] Columns support
-// [SECTION] Settings support
 // [SECTION] Multi-select support
 // [SECTION] Docking support
 // [SECTION] Viewport support
+// [SECTION] Settings support
+// [SECTION] Generic context hooks
 // [SECTION] ImGuiContext (main imgui context)
 // [SECTION] ImGuiWindowTempData, ImGuiWindow
 // [SECTION] Tab bar, Tab item support
 // [SECTION] Table support
 // [SECTION] Internal API
-// [SECTION] Test Engine Hooks (imgui_test_engine)
+// [SECTION] Test Engine specific hooks (imgui_test_engine)
 
 */
 
@@ -93,6 +94,7 @@ struct ImGuiColorMod;               // Stacked color modifier, backup of modifie
 struct ImGuiColumnData;             // Storage data for a single column
 struct ImGuiColumns;                // Storage data for a columns set
 struct ImGuiContext;                // Main Dear ImGui context
+struct ImGuiContextHook;            // Hook for extensions like ImGuiTestEngine
 struct ImGuiDataTypeInfo;           // Type information associated to a ImGuiDataType enum
 struct ImGuiGroupData;              // Stacked storage data for BeginGroup()/EndGroup()
 struct ImGuiInputTextState;         // Internal state of the currently focused/edited text input box
@@ -1099,6 +1101,23 @@ struct ImGuiSettingsHandler
     ImGuiSettingsHandler() { memset(this, 0, sizeof(*this)); }
 };
 
+//-----------------------------------------------------------------------------
+// [SECTION] Generic context hooks
+//-----------------------------------------------------------------------------
+
+typedef void (*ImGuiContextHookCallback)(ImGuiContext* ctx, ImGuiContextHook* hook);
+enum ImGuiContextHookType { ImGuiContextHookType_NewFramePre, ImGuiContextHookType_NewFramePost, ImGuiContextHookType_EndFramePre, ImGuiContextHookType_EndFramePost, ImGuiContextHookType_RenderPre, ImGuiContextHookType_RenderPost, ImGuiContextHookType_Shutdown };
+
+struct ImGuiContextHook
+{
+    ImGuiContextHookType        Type;
+    ImGuiID                     Owner;
+    ImGuiContextHookCallback    Callback;
+    void*                       UserData;
+
+    ImGuiContextHook()          { memset(this, 0, sizeof(*this)); }
+};
+
 //-----------------------------------------------------------------------------
 // [SECTION] ImGuiContext (main imgui context)
 //-----------------------------------------------------------------------------
@@ -1301,6 +1320,7 @@ struct ImGuiContext
     ImGuiTextBuffer         SettingsIniData;                    // In memory .ini settings
     ImVector<ImGuiSettingsHandler>      SettingsHandlers;       // List of .ini settings handlers
     ImChunkStream<ImGuiWindowSettings>  SettingsWindows;        // ImGuiWindow .ini settings entries
+    ImVector<ImGuiContextHook>          Hooks;                  // Hooks for extensions (e.g. test engine)
 
     // Capture/Logging
     bool                    LogEnabled;                         // Currently capturing
@@ -1819,6 +1839,10 @@ namespace ImGui
     IMGUI_API void          UpdateMouseMovingWindowNewFrame();
     IMGUI_API void          UpdateMouseMovingWindowEndFrame();
 
+    // Generic context hooks
+    IMGUI_API void          AddContextHook(ImGuiContext* context, const ImGuiContextHook* hook);
+    IMGUI_API void          CallContextHooks(ImGuiContext* context, ImGuiContextHookType type);
+
     // Settings
     IMGUI_API void                  MarkIniSettingsDirty();
     IMGUI_API void                  MarkIniSettingsDirty(ImGuiWindow* window);
@@ -2055,13 +2079,10 @@ IMGUI_API void              ImFontAtlasBuildMultiplyCalcLookupTable(unsigned cha
 IMGUI_API void              ImFontAtlasBuildMultiplyRectAlpha8(const unsigned char table[256], unsigned char* pixels, int x, int y, int w, int h, int stride);
 
 //-----------------------------------------------------------------------------
-// [SECTION] Test Engine Hooks (imgui_test_engine)
+// [SECTION] Test Engine specific hooks (imgui_test_engine)
 //-----------------------------------------------------------------------------
 
 #ifdef IMGUI_ENABLE_TEST_ENGINE
-extern void                 ImGuiTestEngineHook_Shutdown(ImGuiContext* ctx);
-extern void                 ImGuiTestEngineHook_PreNewFrame(ImGuiContext* ctx);
-extern void                 ImGuiTestEngineHook_PostNewFrame(ImGuiContext* ctx);
 extern void                 ImGuiTestEngineHook_ItemAdd(ImGuiContext* ctx, const ImRect& bb, ImGuiID id);
 extern void                 ImGuiTestEngineHook_ItemInfo(ImGuiContext* ctx, ImGuiID id, const char* label, ImGuiItemStatusFlags flags);
 extern void                 ImGuiTestEngineHook_IdInfo(ImGuiContext* ctx, ImGuiDataType data_type, ImGuiID id, const void* data_id);
@@ -2080,6 +2101,8 @@ extern void                 ImGuiTestEngineHook_Log(ImGuiContext* ctx, const cha
 #define IMGUI_TEST_ENGINE_ID_INFO2(_ID,_TYPE,_DATA,_DATA2)  do { } while (0)
 #endif
 
+//-----------------------------------------------------------------------------
+
 #if defined(__clang__)
 #pragma clang diagnostic pop
 #elif defined(__GNUC__)