IO: removed io.MetricsActiveAllocations introduced in 1.63. Same as 'g.DebugMemAllocCount - g.DebugMemFreeCount' (still displayed in Metrics.

docs/CHANGELOG.txt

@@ -44,6 +44,8 @@ Breaking changes:
 
  - Debug Tools: Renamed ShowStackToolWindow() ("Stack Tool") to ShowIdStackToolWindow() ("ID Stack Tool"),
    as earlier name was misleading. Kept inline redirection function. (#4631)
+ - IO: Removed io.MetricsActiveAllocations introduced in 1.63, was displayed in Metrics and unlikely to
+   be accessed by end-user. Value still visible in the UI and easily to recompute from a delta.
  - ListBox, Combo: Changed signature of "name getter" callback in old one-liner ListBox()/Combo() apis.
    Before:
       getter type:   bool (*getter)(void* user_data, int idx, const char** out_text)
@@ -103,6 +105,7 @@ Other changes:
   Was most often noticable when using an horizontal scrollbar. (#6789)
 - Misc: Most text functions also treat "%.*s" (along with "%s") specially to avoid formatting. (#3466, #6846)
 - IO: Setting io.WantSetMousePos ignores incoming MousePos events. (#6837, #228) [@bertaye]
+- Debug Tools: Metrics: Added log recent alloc/free calls.
 - ImDrawList: Added AddEllipse(), AddEllipseFilled(), PathEllipticalArcTo(). (#2743) [@Doohl]
 - ImVector: Added find_index() helper.
 - Backends: GLFW: Clear emscripten's MouseWheel callback before shutdown. (#6790, #6096, #4019) [@halx99]

imgui.cpp

@@ -424,6 +424,7 @@ CODE
  When you are not sure about an old symbol or function name, try using the Search/Find function of your IDE to look for comments or references in all imgui files.
  You can read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2023/09/27 (1.90.0) - io: removed io.MetricsActiveAllocations introduced in 1.63. Same as 'g.DebugMemAllocCount - g.DebugMemFreeCount' (still displayed in Metrics, unlikely to be accessed by end-user).
  - 2023/09/26 (1.90.0) - debug tools: Renamed ShowStackToolWindow() ("Stack Tool") to ShowIdStackToolWindow() ("ID Stack Tool"), as earlier name was misleading. Kept inline redirection function. (#4631)
  - 2023/09/15 (1.90.0) - ListBox, Combo: changed signature of "name getter" callback in old one-liner ListBox()/Combo() apis. kept inline redirection function (will obsolete).
                            - old: bool Combo(const char* label, int* current_item, bool (*getter)(void* user_data, int idx, const char** out_text), ...)
@@ -4223,26 +4224,50 @@ float ImGui::CalcWrapWidthForPos(const ImVec2& pos, float wrap_pos_x)
 void* ImGui::MemAlloc(size_t size)
 {
     void* ptr = (*GImAllocatorAllocFunc)(size, GImAllocatorUserData);
+#ifndef IMGUI_DISABLE_DEBUG_TOOLS
     if (ImGuiContext* ctx = GImGui)
-    {
-        ctx->IO.MetricsActiveAllocations++;
-        //printf("[%05d] MemAlloc(%d) -> 0x%p\n", ctx->FrameCount, size, ptr);
-    }
+        DebugAllocHook(&ctx->DebugAllocInfo, ctx->FrameCount, ptr, size);
+#endif
     return ptr;
 }
 
 // IM_FREE() == ImGui::MemFree()
 void ImGui::MemFree(void* ptr)
 {
+#ifndef IMGUI_DISABLE_DEBUG_TOOLS
     if (ptr != NULL)
         if (ImGuiContext* ctx = GImGui)
-        {
-            ctx->IO.MetricsActiveAllocations--;
-            //printf("[%05d] MemFree(0x%p)\n", ctx->FrameCount, ptr);
-        }
+            DebugAllocHook(&ctx->DebugAllocInfo, ctx->FrameCount, ptr, (size_t)-1);
+#endif
     return (*GImAllocatorFreeFunc)(ptr, GImAllocatorUserData);
 }
 
+// We record the number of allocation in recent frames, as a way to audit/sanitize our guiding principles of "no allocations on idle/repeating frames"
+void ImGui::DebugAllocHook(ImGuiDebugAllocInfo* info, int frame_count, void* ptr, size_t size)
+{
+    ImGuiDebugAllocEntry* entry = &info->LastEntriesBuf[info->LastEntriesIdx];
+    IM_UNUSED(ptr);
+    if (entry->FrameCount != frame_count)
+    {
+        info->LastEntriesIdx = (info->LastEntriesIdx + 1) % IM_ARRAYSIZE(info->LastEntriesBuf);
+        entry = &info->LastEntriesBuf[info->LastEntriesIdx];
+        entry->FrameCount = frame_count;
+        entry->AllocCount = entry->FreeCount = 0;
+    }
+    if (size != (size_t)-1)
+    {
+        entry->AllocCount++;
+        info->TotalAllocCount++;
+        //printf("[%05d] MemAlloc(%d) -> 0x%p\n", frame_count, size, ptr);
+    }
+    else
+    {
+        entry->FreeCount++;
+        info->TotalFreeCount++;
+        //printf("[%05d] MemFree(0x%p)\n", frame_count, ptr);
+    }
+}
+
 const char* ImGui::GetClipboardText()
 {
     ImGuiContext& g = *GImGui;
@@ -13720,7 +13745,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     Text("Dear ImGui %s", GetVersion());
     Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
     Text("%d vertices, %d indices (%d triangles)", io.MetricsRenderVertices, io.MetricsRenderIndices, io.MetricsRenderIndices / 3);
-    Text("%d visible windows, %d active allocations", io.MetricsRenderWindows, io.MetricsActiveAllocations);
+    Text("%d visible windows, %d current allocations", io.MetricsRenderWindows, g.DebugAllocInfo.TotalAllocCount - g.DebugAllocInfo.TotalFreeCount);
     //SameLine(); if (SmallButton("GC")) { g.GcCompactAll = true; }
 
     Separator();
@@ -14034,6 +14059,20 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         TreePop();
     }
 
+    // Settings
+    if (TreeNode("Memory allocations"))
+    {
+        ImGuiDebugAllocInfo* info = &g.DebugAllocInfo;
+        Text("%d current allocations", info->TotalAllocCount - info->TotalFreeCount);
+        int buf_size = IM_ARRAYSIZE(info->LastEntriesBuf);
+        for (int n = buf_size - 1; n >= 0; n--)
+        {
+            ImGuiDebugAllocEntry* entry = &info->LastEntriesBuf[(info->LastEntriesIdx - n + buf_size) % buf_size];
+            BulletText("Frame %06d: %+3d ( %2d malloc, %2d free )", entry->FrameCount, entry->AllocCount - entry->FreeCount, entry->AllocCount, entry->FreeCount);
+        }
+        TreePop();
+    }
+
     if (TreeNode("Inputs"))
     {
         Text("KEYBOARD/GAMEPAD/MOUSE KEYS");

imgui.h

@@ -2039,11 +2039,6 @@ struct ImGuiIO
     // Optional: Notify OS Input Method Editor of the screen position of your cursor for text input position (e.g. when using Japanese/Chinese IME on Windows)
     // (default to use native imm32 api on Windows)
     void        (*SetPlatformImeDataFn)(ImGuiViewport* viewport, ImGuiPlatformImeData* data);
-#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
-    void*       ImeWindowHandle;                // = NULL           // [Obsoleted in 1.87] Set ImGuiViewport::PlatformHandleRaw instead. Set this to your HWND to get automatic IME cursor positioning.
-#else
-    void*       _UnusedPadding;                                     // Unused field to keep data structure the same size.
-#endif
 
     // Optional: Platform locale
     ImWchar     PlatformLocaleDecimalPoint;     // '.'              // [Experimental] Configure decimal point e.g. '.' or ',' useful for some languages (e.g. German), generally pulled from *localeconv()->decimal_point
@@ -2090,7 +2085,6 @@ struct ImGuiIO
     int         MetricsRenderIndices;               // Indices output during last call to Render() = number of triangles * 3
     int         MetricsRenderWindows;               // Number of visible windows
     int         MetricsActiveWindows;               // Number of active windows
-    int         MetricsActiveAllocations;           // Number of active allocations, updated by MemAlloc/MemFree based on current context. May be off if you have multiple imgui contexts.
     ImVec2      MouseDelta;                         // Mouse delta. Note that this is zero if either current or previous position are invalid (-FLT_MAX,-FLT_MAX), so a disappearing/reappearing mouse won't have a huge delta.
 
     // Legacy: before 1.87, we required backend to fill io.KeyMap[] (imgui->native map) during initialization and io.KeysDown[] (native indices) every frame.
@@ -2101,6 +2095,11 @@ struct ImGuiIO
     bool        KeysDown[ImGuiKey_COUNT];           // [LEGACY] Input: Keyboard keys that are pressed (ideally left in the "native" order your engine has access to keyboard keys, so you can use your own defines/enums for keys). This used to be [512] sized. It is now ImGuiKey_COUNT to allow legacy io.KeysDown[GetKeyIndex(...)] to work without an overflow.
     float       NavInputs[ImGuiNavInput_COUNT];     // [LEGACY] Since 1.88, NavInputs[] was removed. Backends from 1.60 to 1.86 won't build. Feed gamepad inputs via io.AddKeyEvent() and ImGuiKey_GamepadXXX enums.
 #endif
+#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+    void*       ImeWindowHandle;                    // = NULL   // [Obsoleted in 1.87] Set ImGuiViewport::PlatformHandleRaw instead. Set this to your HWND to get automatic IME cursor positioning.
+#else
+    void*       _UnusedPadding;
+#endif
 
     //------------------------------------------------------------------
     // [Internal] Dear ImGui will maintain those fields. Forward compatibility not guaranteed!

imgui_internal.h

@@ -1783,6 +1783,23 @@ enum ImGuiDebugLogFlags_
     ImGuiDebugLogFlags_OutputToTestEngine = 1 << 11,  // Also send output to Test Engine
 };
 
+struct ImGuiDebugAllocEntry
+{
+    int         FrameCount;
+    ImS16       AllocCount;
+    ImS16       FreeCount;
+};
+
+struct ImGuiDebugAllocInfo
+{
+    int         TotalAllocCount;            // Number of call to MemAlloc().
+    int         TotalFreeCount;
+    ImS16       LastEntriesIdx;             // Current index in buffer
+    ImGuiDebugAllocEntry LastEntriesBuf[6]; // Track last 6 frames that had allocations
+
+    ImGuiDebugAllocInfo() { memset(this, 0, sizeof(*this)); }
+};
+
 struct ImGuiMetricsConfig
 {
     bool        ShowDebugLog = false;
@@ -2133,6 +2150,7 @@ struct ImGuiContext
     ImGuiID                 DebugItemPickerBreakId;             // Will call IM_DEBUG_BREAK() when encountering this ID
     ImGuiMetricsConfig      DebugMetricsConfig;
     ImGuiIdStackTool        DebugIdStackTool;
+    ImGuiDebugAllocInfo     DebugAllocInfo;
 
     // Misc
     float                   FramerateSecPerFrame[60];           // Calculate estimate of framerate for user over the last 60 frames..
@@ -3326,6 +3344,7 @@ namespace ImGui
     // Debug Log
     IMGUI_API void          DebugLog(const char* fmt, ...) IM_FMTARGS(1);
     IMGUI_API void          DebugLogV(const char* fmt, va_list args) IM_FMTLIST(1);
+    IMGUI_API void          DebugAllocHook(ImGuiDebugAllocInfo* info, int frame_count, void* ptr, size_t size); // size >= 0 : alloc, size = -1 : free
 
     // Debug Tools
     IMGUI_API void          ErrorCheckEndFrameRecover(ImGuiErrorLogCallback log_callback, void* user_data = NULL);