Added a mechanism to compact/free the larger allocations of unused windows (buffers are compacted when a window is unused for 60 seconds, as per io.ConfigWindowsMemoryCompactTimer = 60.0f). Note that memory usage has never been reported as a problem, so this is merely a touch of overzealous luxury. (#2636)
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index d9a6076..9dee419 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -42,6 +42,9 @@
- SliderScalar: Improved assert when using U32 or U64 types with a large v_max value. (#2765) [@loicmouton]
- ImDrawList: clarified the name of many parameters so reading the code is a little easier. (#2740)
- Using offsetof() when available in C++11. Avoids Clang sanitizer complaining about old-style macros. (#94)
+- Added a mechanism to compact/free the larger allocations of unused windows (buffers are compacted when
+ a window is unused for 60 seconds, as per io.ConfigWindowsMemoryCompactTimer = 60.0f). Note that memory
+ usage has never been reported as a problem, so this is merely a touch of overzealous luxury. (#2636)
- Backends: DX11: Fixed GSGetShader() call not passing an initialized instance count,
would generally make the debug layer complain (Added in 1.72).
- Backends: Vulkan: Added support for specifying multisample count.
diff --git a/imgui.cpp b/imgui.cpp
index fbe7a29..6a8cc17 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -1244,6 +1244,7 @@
ConfigInputTextCursorBlink = true;
ConfigWindowsResizeFromEdges = true;
ConfigWindowsMoveFromTitleBarOnly = false;
+ ConfigWindowsMemoryCompactTimer = 60.0f;
// Platform Functions
BackendPlatformName = BackendRendererName = NULL;
@@ -2699,6 +2700,7 @@
SetWindowPosVal = SetWindowPosPivot = ImVec2(FLT_MAX, FLT_MAX);
LastFrameActive = -1;
+ LastTimeActive = -1.0f;
ItemWidthDefault = 0.0f;
FontWindowScale = 1.0f;
SettingsIdx = -1;
@@ -2713,6 +2715,9 @@
NavLastIds[0] = NavLastIds[1] = 0;
NavRectRel[0] = NavRectRel[1] = ImRect();
NavLastChildNavWindow = NULL;
+
+ MemoryCompacted = false;
+ MemoryDrawListIdxCapacity = MemoryDrawListVtxCapacity = 0;
}
ImGuiWindow::~ImGuiWindow()
@@ -2783,6 +2788,36 @@
g.FontSize = g.DrawListSharedData.FontSize = window->CalcFontSize();
}
+// Free up/compact internal window buffers, we can use this when a window becomes unused.
+// This is currently unused by the library, but you may call this yourself for easy GC.
+// Not freed:
+// - ImGuiWindow, ImGuiWindowSettings, Name
+// - StateStorage, ColumnsStorage (may hold useful data)
+// This should have no noticeable visual effect. When the window reappear however, expect new allocation/buffer growth/copy cost.
+void ImGui::GcCompactTransientWindowBuffers(ImGuiWindow* window)
+{
+ window->MemoryCompacted = true;
+ window->MemoryDrawListIdxCapacity = window->DrawList->IdxBuffer.Capacity;
+ window->MemoryDrawListVtxCapacity = window->DrawList->VtxBuffer.Capacity;
+ window->IDStack.clear();
+ window->DrawList->ClearFreeMemory();
+ window->DC.ChildWindows.clear();
+ window->DC.ItemFlagsStack.clear();
+ window->DC.ItemWidthStack.clear();
+ window->DC.TextWrapPosStack.clear();
+ window->DC.GroupStack.clear();
+}
+
+void ImGui::GcAwakeTransientWindowBuffers(ImGuiWindow* window)
+{
+ // We stored capacity of the ImDrawList buffer to reduce growth-caused allocation/copy when awakening.
+ // The other buffers tends to amortize much faster.
+ window->MemoryCompacted = false;
+ window->DrawList->IdxBuffer.reserve(window->MemoryDrawListIdxCapacity);
+ window->DrawList->VtxBuffer.reserve(window->MemoryDrawListVtxCapacity);
+ window->MemoryDrawListIdxCapacity = window->MemoryDrawListVtxCapacity = 0;
+}
+
void ImGui::SetNavID(ImGuiID id, int nav_layer)
{
ImGuiContext& g = *GImGui;
@@ -3814,8 +3849,9 @@
g.NavIdTabCounter = INT_MAX;
- // Mark all windows as not visible
+ // Mark all windows as not visible and compact unused memory.
IM_ASSERT(g.WindowsFocusOrder.Size == g.Windows.Size);
+ const float memory_compact_start_time = (g.IO.ConfigWindowsMemoryCompactTimer > 0.0f) ? (float)g.Time - g.IO.ConfigWindowsMemoryCompactTimer : FLT_MAX;
for (int i = 0; i != g.Windows.Size; i++)
{
ImGuiWindow* window = g.Windows[i];
@@ -3823,6 +3859,10 @@
window->BeginCount = 0;
window->Active = false;
window->WriteAccessed = false;
+
+ // Garbage collect (this is totally functional but we may need decide if the side-effects are desirable)
+ if (!window->WasActive && !window->MemoryCompacted && window->LastTimeActive < memory_compact_start_time)
+ GcCompactTransientWindowBuffers(window);
}
// Closing the focused window restore focus to the first active root window in descending z-order
@@ -5391,6 +5431,7 @@
{
window->Flags = (ImGuiWindowFlags)flags;
window->LastFrameActive = current_frame;
+ window->LastTimeActive = (float)g.Time;
window->BeginOrderWithinParent = 0;
window->BeginOrderWithinContext = (short)(g.WindowsActiveCount++);
}
@@ -5404,6 +5445,10 @@
ImGuiWindow* parent_window = first_begin_of_the_frame ? ((flags & (ImGuiWindowFlags_ChildWindow | ImGuiWindowFlags_Popup)) ? parent_window_in_stack : NULL) : window->ParentWindow;
IM_ASSERT(parent_window != NULL || !(flags & ImGuiWindowFlags_ChildWindow));
+ // We allow window memory to be compacted so recreate the base stack when needed.
+ if (window->IDStack.Size == 0)
+ window->IDStack.push_back(window->ID);
+
// Add to stack
// We intentionally set g.CurrentWindow to NULL to prevent usage until when the viewport is set, then will call SetCurrentWindow()
g.CurrentWindowStack.push_back(window);
@@ -5468,6 +5513,10 @@
window->ClipRect = ImVec4(-FLT_MAX,-FLT_MAX,+FLT_MAX,+FLT_MAX);
window->IDStack.resize(1);
+ // Restore buffer capacity when woken from a compacted state, to avoid
+ if (window->MemoryCompacted)
+ GcAwakeTransientWindowBuffers(window);
+
// Update stored window name when it changes (which can _only_ happen with the "###" operator, so the ID would stay unchanged).
// The title bar always display the 'name' parameter, so we only update the string storage if it needs to be visible to the end-user elsewhere.
bool window_title_visible_elsewhere = false;
diff --git a/imgui.h b/imgui.h
index 6b0de93..28c7d20 100644
--- a/imgui.h
+++ b/imgui.h
@@ -1360,6 +1360,7 @@
bool ConfigInputTextCursorBlink; // = true // Set to false to disable blinking cursor, for users who consider it distracting. (was called: io.OptCursorBlink prior to 1.63)
bool ConfigWindowsResizeFromEdges; // = true // Enable resizing of windows from their edges and from the lower-left corner. This requires (io.BackendFlags & ImGuiBackendFlags_HasMouseCursors) because it needs mouse cursor feedback. (This used to be a per-window ImGuiWindowFlags_ResizeFromAnySide flag)
bool ConfigWindowsMoveFromTitleBarOnly; // = false // [BETA] Set to true to only allow moving windows when clicked+dragged from the title bar. Windows without a title bar are not affected.
+ float ConfigWindowsMemoryCompactTimer;// = 60.0f // [BETA] Compact window memory usage when unused. Set to 0.0f to disable.
//------------------------------------------------------------------
// Platform Functions
diff --git a/imgui_demo.cpp b/imgui_demo.cpp
index 0421443..568da3b 100644
--- a/imgui_demo.cpp
+++ b/imgui_demo.cpp
@@ -3049,6 +3049,7 @@
if (io.ConfigInputTextCursorBlink) ImGui::Text("io.ConfigInputTextCursorBlink");
if (io.ConfigWindowsResizeFromEdges) ImGui::Text("io.ConfigWindowsResizeFromEdges");
if (io.ConfigWindowsMoveFromTitleBarOnly) ImGui::Text("io.ConfigWindowsMoveFromTitleBarOnly");
+ if (io.ConfigWindowsMemoryCompactTimer > 0.0f) ImGui::Text("io.ConfigWindowsMemoryCompactTimer = %.1ff", io.ConfigWindowsMemoryCompactTimer);
ImGui::Text("io.BackendFlags: 0x%08X", io.BackendFlags);
if (io.BackendFlags & ImGuiBackendFlags_HasGamepad) ImGui::Text(" HasGamepad");
if (io.BackendFlags & ImGuiBackendFlags_HasMouseCursors) ImGui::Text(" HasMouseCursors");
diff --git a/imgui_internal.h b/imgui_internal.h
index a936f69..1018b1e 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -1321,8 +1321,8 @@
ImVec2 SetWindowPosVal; // store window position when using a non-zero Pivot (position set needs to be processed when we know the window size)
ImVec2 SetWindowPosPivot; // store window pivot for positioning. ImVec2(0,0) when positioning from top-left corner; ImVec2(0.5f,0.5f) for centering; ImVec2(1,1) for bottom right.
+ ImVector<ImGuiID> IDStack; // ID stack. ID are hashes seeded with the value at the top of the stack. (In theory this should be in the TempData structure)
ImGuiWindowTempData DC; // Temporary per-window data, reset at the beginning of the frame. This used to be called ImGuiDrawContext, hence the "DC" variable name.
- ImVector<ImGuiID> IDStack; // ID stack. ID are hashes seeded with the value at the top of the stack
// The best way to understand what those rectangles are is to use the 'Metrics -> Tools -> Show windows rectangles' viewer.
// The main 'OuterRect', omitted as a field, is window->Rect().
@@ -1334,6 +1334,7 @@
ImRect ContentsRegionRect; // FIXME: This is currently confusing/misleading. It is essentially WorkRect but not handling of scrolling. We currently rely on it as right/bottom aligned sizing operation need some size to rely on.
int LastFrameActive; // Last frame number the window was Active.
+ float LastTimeActive;
float ItemWidthDefault;
ImGuiMenuColumns MenuColumns; // Simplified columns storage for menu items
ImGuiStorage StateStorage;
@@ -1352,6 +1353,10 @@
ImGuiID NavLastIds[ImGuiNavLayer_COUNT]; // Last known NavId for this window, per layer (0/1)
ImRect NavRectRel[ImGuiNavLayer_COUNT]; // Reference rectangle, in window relative space
+ bool MemoryCompacted;
+ int MemoryDrawListIdxCapacity;
+ int MemoryDrawListVtxCapacity;
+
public:
ImGuiWindow(ImGuiContext* context, const char* name);
~ImGuiWindow();
@@ -1483,6 +1488,8 @@
IMGUI_API void SetWindowPos(ImGuiWindow* window, const ImVec2& pos, ImGuiCond cond = 0);
IMGUI_API void SetWindowSize(ImGuiWindow* window, const ImVec2& size, ImGuiCond cond = 0);
IMGUI_API void SetWindowCollapsed(ImGuiWindow* window, bool collapsed, ImGuiCond cond = 0);
+ IMGUI_API void GcCompactTransientWindowBuffers(ImGuiWindow* window);
+ IMGUI_API void GcAwakeTransientWindowBuffers(ImGuiWindow* window);
IMGUI_API void SetCurrentFont(ImFont* font);
inline ImFont* GetDefaultFont() { ImGuiContext& g = *GImGui; return g.IO.FontDefault ? g.IO.FontDefault : g.IO.Fonts->Fonts[0]; }
