Merge branch 'master' into docking

# Conflicts:
#	imgui.cpp
#	imgui.h
#	imgui_internal.h

docs/CHANGELOG.txt

@@ -106,9 +106,20 @@ Breaking changes:
 - IO: Obsoleted io.ClearInputCharacters() (added in 1.47) as it now ambiguous
   and often incorrect/misleading considering the existence of a higher-level
   input queue. (#4921)
+- ImDrawData: CmdLists[] arra is now owned, changed from 'ImDrawList**' to
+  'ImVector<ImDrawList*>'. Majority of users shouldn't be affected, but you
+  cannot compare to NULL nor reassign manually anymore.
+  Instead use AddDrawList(). (#6406, #4879, #1878)
 
 Other changes:
 
+- ImDrawData: CmdLists[] array is now an ImVector<> owned by ImDrawData rather
+  than a pointer to internal state.
+  - This makes it easier for user to create their own or append to an existing draw data.
+    Added a ImDrawData::AddDrawList() helper function to do that. (#6406, #4879, #1878)
+  - This makes it easier to perform a deep-swap instead of a deep-copy, as array
+    ownership is now clear. (#6597, #6475, #6167, #5776, #5109, #4763, #3515, #1860)
+  - Syntax and allocation count are otherwise identical.
 - Fixed CTRL+Tab dimming background assert when target window has a callback
   in the last ImDrawCmd. (#4857, #5937)
 - InputText: Fixed a case where deactivation frame would write to underlying

imgui.cpp

@@ -407,6 +407,7 @@ CODE
                           - likewise io.MousePos and GetMousePos() will use OS coordinates.
                             If you query mouse positions to interact with non-imgui coordinates you will need to offset them, e.g. subtract GetWindowViewport()->Pos.
 
+ - 2023/07/12 (1.89.8) - ImDrawData: CmdLists now owned, changed from ImDrawList** to ImVector<ImDrawList*>. Majority of users shouldn't be affected, but you cannot compare to NULL nor reassign manually anymore. Instead use AddDrawList(). (#6406, #4879, #1878)
  - 2023/06/28 (1.89.7) - overlapping items: obsoleted 'SetItemAllowOverlap()' (called after item) in favor of calling 'SetNextItemAllowOverlap()' (called before item). 'SetItemAllowOverlap()' didn't and couldn't work reliably since 1.89 (2022-11-15).
  - 2023/06/28 (1.89.7) - overlapping items: renamed 'ImGuiTreeNodeFlags_AllowItemOverlap' to 'ImGuiTreeNodeFlags_AllowOverlap', 'ImGuiSelectableFlags_AllowItemOverlap' to 'ImGuiSelectableFlags_AllowOverlap'. Kept redirecting enums (will obsolete).
  - 2023/06/28 (1.89.7) - overlapping items: IsItemHovered() now by default return false when querying an item using AllowOverlap mode which is being overlapped. Use ImGuiHoveredFlags_AllowWhenOverlappedByItem to revert to old behavior.
@@ -1022,7 +1023,6 @@ static void             FindHoveredWindow();
 static ImGuiWindow*     CreateNewWindow(const char* name, ImGuiWindowFlags flags);
 static ImVec2           CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window);
 
-static void             AddDrawListToDrawData(ImVector<ImDrawList*>* out_list, ImDrawList* draw_list);
 static void             AddWindowToSortBuffer(ImVector<ImGuiWindow*>* out_sorted_windows, ImGuiWindow* window);
 
 // Settings
@@ -2977,7 +2977,7 @@ static bool ImGuiListClipper_StepInternal(ImGuiListClipper* clipper)
             const bool is_nav_request = (g.NavMoveScoringItems && g.NavWindow && g.NavWindow->RootWindowForNav == window->RootWindowForNav);
             if (is_nav_request)
                 data->Ranges.push_back(ImGuiListClipperRange::FromPositions(g.NavScoringNoClipRect.Min.y, g.NavScoringNoClipRect.Max.y, 0, 0));
-            if (is_nav_request && (g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) && g.NavTabbingDir == -1)
+            if (is_nav_request && (g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing) && g.NavTabbingDir == -1)
                 data->Ranges.push_back(ImGuiListClipperRange::FromIndices(clipper->ItemsCount - 1, clipper->ItemsCount));
 
             // Add focused/active item
@@ -4978,41 +4978,6 @@ static void AddWindowToSortBuffer(ImVector<ImGuiWindow*>* out_sorted_windows, Im
     }
 }
 
-static void AddDrawListToDrawData(ImVector<ImDrawList*>* out_list, ImDrawList* draw_list)
-{
-    if (draw_list->CmdBuffer.Size == 0)
-        return;
-    if (draw_list->CmdBuffer.Size == 1 && draw_list->CmdBuffer[0].ElemCount == 0 && draw_list->CmdBuffer[0].UserCallback == NULL)
-        return;
-
-    // Draw list sanity check. Detect mismatch between PrimReserve() calls and incrementing _VtxCurrentIdx, _VtxWritePtr etc.
-    // May trigger for you if you are using PrimXXX functions incorrectly.
-    IM_ASSERT(draw_list->VtxBuffer.Size == 0 || draw_list->_VtxWritePtr == draw_list->VtxBuffer.Data + draw_list->VtxBuffer.Size);
-    IM_ASSERT(draw_list->IdxBuffer.Size == 0 || draw_list->_IdxWritePtr == draw_list->IdxBuffer.Data + draw_list->IdxBuffer.Size);
-    if (!(draw_list->Flags & ImDrawListFlags_AllowVtxOffset))
-        IM_ASSERT((int)draw_list->_VtxCurrentIdx == draw_list->VtxBuffer.Size);
-
-    // Check that draw_list doesn't use more vertices than indexable (default ImDrawIdx = unsigned short = 2 bytes = 64K vertices per ImDrawList = per window)
-    // If this assert triggers because you are drawing lots of stuff manually:
-    // - First, make sure you are coarse clipping yourself and not trying to draw many things outside visible bounds.
-    //   Be mindful that the ImDrawList API doesn't filter vertices. Use the Metrics/Debugger window to inspect draw list contents.
-    // - If you want large meshes with more than 64K vertices, you can either:
-    //   (A) Handle the ImDrawCmd::VtxOffset value in your renderer backend, and set 'io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset'.
-    //       Most example backends already support this from 1.71. Pre-1.71 backends won't.
-    //       Some graphics API such as GL ES 1/2 don't have a way to offset the starting vertex so it is not supported for them.
-    //   (B) Or handle 32-bit indices in your renderer backend, and uncomment '#define ImDrawIdx unsigned int' line in imconfig.h.
-    //       Most example backends already support this. For example, the OpenGL example code detect index size at compile-time:
-    //         glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer_offset);
-    //       Your own engine or render API may use different parameters or function calls to specify index sizes.
-    //       2 and 4 bytes indices are generally supported by most graphics API.
-    // - If for some reason neither of those solutions works for you, a workaround is to call BeginChild()/EndChild() before reaching
-    //   the 64K limit to split your draw commands in multiple draw lists.
-    if (sizeof(ImDrawIdx) == 2)
-        IM_ASSERT(draw_list->_VtxCurrentIdx < (1 << 16) && "Too many vertices in ImDrawList using 16-bit indices. Read comment above");
-
-    out_list->push_back(draw_list);
-}
-
 static void AddWindowToDrawData(ImGuiWindow* window, int layer)
 {
     ImGuiContext& g = *GImGui;
@@ -5021,7 +4986,7 @@ static void AddWindowToDrawData(ImGuiWindow* window, int layer)
     g.IO.MetricsRenderWindows++;
     if (window->Flags & ImGuiWindowFlags_DockNodeHost)
         window->DrawList->ChannelsMerge();
-    AddDrawListToDrawData(&viewport->DrawDataBuilder.Layers[layer], window->DrawList);
+    ImGui::AddDrawListToDrawDataEx(&viewport->DrawDataP, viewport->DrawDataBuilder.Layers[layer], window->DrawList);
     for (int i = 0; i < window->DC.ChildWindows.Size; i++)
     {
         ImGuiWindow* child = window->DC.ChildWindows[i];
@@ -5041,26 +5006,35 @@ static inline void AddRootWindowToDrawData(ImGuiWindow* window)
     AddWindowToDrawData(window, GetWindowDisplayLayer(window));
 }
 
-void ImDrawDataBuilder::FlattenIntoSingleLayer()
+static void FlattenDrawDataIntoSingleLayer(ImDrawDataBuilder* builder)
 {
-    int n = Layers[0].Size;
-    int size = n;
-    for (int i = 1; i < IM_ARRAYSIZE(Layers); i++)
-        size += Layers[i].Size;
-    Layers[0].resize(size);
-    for (int layer_n = 1; layer_n < IM_ARRAYSIZE(Layers); layer_n++)
+    int n = builder->Layers[0]->Size;
+    int full_size = n;
+    for (int i = 1; i < IM_ARRAYSIZE(builder->Layers); i++)
+        full_size += builder->Layers[i]->Size;
+    builder->Layers[0]->resize(full_size);
+    for (int layer_n = 1; layer_n < IM_ARRAYSIZE(builder->Layers); layer_n++)
     {
-        ImVector<ImDrawList*>& layer = Layers[layer_n];
-        if (layer.empty())
+        ImVector<ImDrawList*>* layer = builder->Layers[layer_n];
+        if (layer->empty())
             continue;
-        memcpy(&Layers[0][n], &layer[0], layer.Size * sizeof(ImDrawList*));
-        n += layer.Size;
-        layer.resize(0);
+        memcpy(builder->Layers[0]->Data + n, layer->Data, layer->Size * sizeof(ImDrawList*));
+        n += layer->Size;
+        layer->resize(0);
     }
 }
 
-static void SetupViewportDrawData(ImGuiViewportP* viewport, ImVector<ImDrawList*>* draw_lists)
+static void InitViewportDrawData(ImGuiViewportP* viewport)
 {
+    ImGuiIO& io = ImGui::GetIO();
+    ImDrawData* draw_data = &viewport->DrawDataP;
+
+    viewport->DrawData = draw_data; // Make publicly accessible
+    viewport->DrawDataBuilder.Layers[0] = &draw_data->CmdLists;
+    viewport->DrawDataBuilder.Layers[1] = &viewport->DrawDataBuilder.LayerData1;
+    viewport->DrawDataBuilder.Layers[0]->resize(0);
+    viewport->DrawDataBuilder.Layers[1]->resize(0);
+
     // When minimized, we report draw_data->DisplaySize as zero to be consistent with non-viewport mode,
     // and to allow applications/backends to easily skip rendering.
     // FIXME: Note that we however do NOT attempt to report "zero drawlist / vertices" into the ImDrawData structure.
@@ -5068,24 +5042,13 @@ static void SetupViewportDrawData(ImGuiViewportP* viewport, ImVector<ImDrawList*
     // it earlier in the pipeline, rather than pretend to hide the data at the end of the pipeline.
     const bool is_minimized = (viewport->Flags & ImGuiViewportFlags_IsMinimized) != 0;
 
-    ImGuiIO& io = ImGui::GetIO();
-    ImDrawData* draw_data = &viewport->DrawDataP;
-    viewport->DrawData = draw_data; // Make publicly accessible
     draw_data->Valid = true;
-    draw_data->CmdLists = (draw_lists->Size > 0) ? draw_lists->Data : NULL;
-    draw_data->CmdListsCount = draw_lists->Size;
+    draw_data->CmdListsCount = 0;
     draw_data->TotalVtxCount = draw_data->TotalIdxCount = 0;
     draw_data->DisplayPos = viewport->Pos;
     draw_data->DisplaySize = is_minimized ? ImVec2(0.0f, 0.0f) : viewport->Size;
     draw_data->FramebufferScale = io.DisplayFramebufferScale; // FIXME-VIEWPORT: This may vary on a per-monitor/viewport basis?
     draw_data->OwnerViewport = viewport;
-    for (int n = 0; n < draw_lists->Size; n++)
-    {
-        ImDrawList* draw_list = draw_lists->Data[n];
-        draw_list->_PopUnusedDrawCmd();
-        draw_data->TotalVtxCount += draw_list->VtxBuffer.Size;
-        draw_data->TotalIdxCount += draw_list->IdxBuffer.Size;
-    }
 }
 
 // Push a clipping rectangle for both ImGui logic (hit-testing etc.) and low-level ImDrawList rendering.
@@ -5354,9 +5317,9 @@ void ImGui::Render()
     for (int n = 0; n != g.Viewports.Size; n++)
     {
         ImGuiViewportP* viewport = g.Viewports[n];
-        viewport->DrawDataBuilder.Clear();
+        InitViewportDrawData(viewport);
         if (viewport->DrawLists[0] != NULL)
-            AddDrawListToDrawData(&viewport->DrawDataBuilder.Layers[0], GetBackgroundDrawList(viewport));
+            AddDrawListToDrawDataEx(&viewport->DrawDataP, viewport->DrawDataBuilder.Layers[0], GetBackgroundDrawList(viewport));
     }
 
     // Add ImDrawList to render
@@ -5387,14 +5350,14 @@ void ImGui::Render()
     for (int n = 0; n < g.Viewports.Size; n++)
     {
         ImGuiViewportP* viewport = g.Viewports[n];
-        viewport->DrawDataBuilder.FlattenIntoSingleLayer();
+        FlattenDrawDataIntoSingleLayer(&viewport->DrawDataBuilder);
 
         // Add foreground ImDrawList (for each active viewport)
         if (viewport->DrawLists[1] != NULL)
-            AddDrawListToDrawData(&viewport->DrawDataBuilder.Layers[0], GetForegroundDrawList(viewport));
+            AddDrawListToDrawDataEx(&viewport->DrawDataP, viewport->DrawDataBuilder.Layers[0], GetForegroundDrawList(viewport));
 
-        SetupViewportDrawData(viewport, &viewport->DrawDataBuilder.Layers[0]);
-        ImDrawData* draw_data = viewport->DrawData;
+        ImDrawData* draw_data = &viewport->DrawDataP;
+        IM_ASSERT(draw_data->CmdLists.Size == draw_data->CmdListsCount);
         g.IO.MetricsRenderVertices += draw_data->TotalVtxCount;
         g.IO.MetricsRenderIndices += draw_data->TotalIdxCount;
     }
@@ -8268,7 +8231,7 @@ void ImGui::FocusItem()
         return;
     }
 
-    ImGuiNavMoveFlags move_flags = ImGuiNavMoveFlags_Tabbing | ImGuiNavMoveFlags_FocusApi | ImGuiNavMoveFlags_NoSelect;
+    ImGuiNavMoveFlags move_flags = ImGuiNavMoveFlags_IsTabbing | ImGuiNavMoveFlags_FocusApi | ImGuiNavMoveFlags_NoSelect;
     ImGuiScrollFlags scroll_flags = window->Appearing ? ImGuiScrollFlags_KeepVisibleEdgeX | ImGuiScrollFlags_AlwaysCenterY : ImGuiScrollFlags_KeepVisibleEdgeX | ImGuiScrollFlags_KeepVisibleEdgeY;
     SetNavWindow(window);
     NavMoveRequestSubmit(ImGuiDir_None, ImGuiDir_Up, move_flags, scroll_flags);
@@ -8303,7 +8266,7 @@ void ImGui::SetKeyboardFocusHere(int offset)
 
     SetNavWindow(window);
 
-    ImGuiNavMoveFlags move_flags = ImGuiNavMoveFlags_Tabbing | ImGuiNavMoveFlags_Activate | ImGuiNavMoveFlags_FocusApi;
+    ImGuiNavMoveFlags move_flags = ImGuiNavMoveFlags_IsTabbing | ImGuiNavMoveFlags_Activate | ImGuiNavMoveFlags_FocusApi;
     ImGuiScrollFlags scroll_flags = window->Appearing ? ImGuiScrollFlags_KeepVisibleEdgeX | ImGuiScrollFlags_AlwaysCenterY : ImGuiScrollFlags_KeepVisibleEdgeX | ImGuiScrollFlags_KeepVisibleEdgeY;
     NavMoveRequestSubmit(ImGuiDir_None, offset < 0 ? ImGuiDir_Up : ImGuiDir_Down, move_flags, scroll_flags); // FIXME-NAV: Once we refactor tabbing, add LegacyApi flag to not activate non-inputable.
     if (offset == -1)
@@ -11734,7 +11697,7 @@ static void ImGui::NavProcessItem()
     // FIXME-NAV: Consider policy for double scoring (scoring from NavScoringRect + scoring from a rect wrapped according to current wrapping policy)
     if (g.NavMoveScoringItems && (item_flags & ImGuiItemFlags_Disabled) == 0)
     {
-        const bool is_tabbing = (g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) != 0;
+        const bool is_tabbing = (g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing) != 0;
         if (is_tabbing)
         {
             NavProcessItemForTabbingRequest(id, item_flags, g.NavMoveFlags);
@@ -11840,7 +11803,7 @@ void ImGui::NavMoveRequestSubmit(ImGuiDir move_dir, ImGuiDir clip_dir, ImGuiNavM
     ImGuiContext& g = *GImGui;
     IM_ASSERT(g.NavWindow != NULL);
 
-    if (move_flags & ImGuiNavMoveFlags_Tabbing)
+    if (move_flags & ImGuiNavMoveFlags_IsTabbing)
         move_flags |= ImGuiNavMoveFlags_AllowCurrentNavId;
 
     g.NavMoveSubmitted = g.NavMoveScoringItems = true;
@@ -12392,7 +12355,7 @@ void ImGui::NavUpdateCreateTabbingRequest()
         g.NavTabbingDir = g.IO.KeyShift ? -1 : (g.NavDisableHighlight == true && g.ActiveId == 0) ? 0 : +1;
     else
         g.NavTabbingDir = g.IO.KeyShift ? -1 : (g.ActiveId == 0) ? 0 : +1;
-    ImGuiNavMoveFlags move_flags = ImGuiNavMoveFlags_Tabbing | ImGuiNavMoveFlags_Activate;
+    ImGuiNavMoveFlags move_flags = ImGuiNavMoveFlags_IsTabbing | ImGuiNavMoveFlags_Activate;
     ImGuiScrollFlags scroll_flags = window->Appearing ? ImGuiScrollFlags_KeepVisibleEdgeX | ImGuiScrollFlags_AlwaysCenterY : ImGuiScrollFlags_KeepVisibleEdgeX | ImGuiScrollFlags_KeepVisibleEdgeY;
     ImGuiDir clip_dir = (g.NavTabbingDir < 0) ? ImGuiDir_Up : ImGuiDir_Down;
     NavMoveRequestSubmit(ImGuiDir_None, clip_dir, move_flags, scroll_flags); // FIXME-NAV: Once we refactor tabbing, add LegacyApi flag to not activate non-inputable.
@@ -12412,7 +12375,7 @@ void ImGui::NavMoveRequestApplyResult()
     ImGuiNavItemData* result = (g.NavMoveResultLocal.ID != 0) ? &g.NavMoveResultLocal : (g.NavMoveResultOther.ID != 0) ? &g.NavMoveResultOther : NULL;
 
     // Tabbing forward wrap
-    if ((g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) && result == NULL)
+    if ((g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing) && result == NULL)
         if ((g.NavTabbingCounter == 1 || g.NavTabbingDir == 0) && g.NavTabbingResultFirst.ID)
             result = &g.NavTabbingResultFirst;
 
@@ -12420,7 +12383,7 @@ void ImGui::NavMoveRequestApplyResult()
     const ImGuiAxis axis = (g.NavMoveDir == ImGuiDir_Up || g.NavMoveDir == ImGuiDir_Down) ? ImGuiAxis_Y : ImGuiAxis_X;
     if (result == NULL)
     {
-        if (g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing)
+        if (g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing)
             g.NavMoveFlags |= ImGuiNavMoveFlags_NoSetNavHighlight;
         if (g.NavId != 0 && (g.NavMoveFlags & ImGuiNavMoveFlags_NoSetNavHighlight) == 0)
             NavRestoreHighlightAfterMove();
@@ -12461,9 +12424,11 @@ void ImGui::NavMoveRequestApplyResult()
     }
     if (g.ActiveId != result->ID)
         ClearActiveID();
-    if (g.NavId != result->ID && (g.NavMoveFlags & ImGuiNavMoveFlags_NoSelect) == 0)
+
+    // Don't set NavJustMovedToId if just landed on the same spot (which may happen with ImGuiNavMoveFlags_AllowCurrentNavId)
+    // PageUp/PageDown however sets always set NavJustMovedTo (vs Home/End which doesn't) mimicking Windows behavior.
+    if ((g.NavId != result->ID || (g.NavMoveFlags & ImGuiNavMoveFlags_IsPageMove)) && (g.NavMoveFlags & ImGuiNavMoveFlags_NoSelect) == 0)
     {
-        // Don't set NavJustMovedToId if just landed on the same spot (which may happen with ImGuiNavMoveFlags_AllowCurrentNavId)
         g.NavJustMovedToId = result->ID;
         g.NavJustMovedToFocusScopeId = result->FocusScopeId;
         g.NavJustMovedToKeyMods = g.NavMoveKeyMods;
@@ -12476,14 +12441,14 @@ void ImGui::NavMoveRequestApplyResult()
 
     // Restore last preferred position for current axis
     // (storing in RootWindowForNav-> as the info is desirable at the beginning of a Move Request. In theory all storage should use RootWindowForNav..)
-    if ((g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) == 0)
+    if ((g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing) == 0)
     {
         preferred_scoring_pos_rel[axis] = result->RectRel.GetCenter()[axis];
         g.NavWindow->RootWindowForNav->NavPreferredScoringPosRel[g.NavLayer] = preferred_scoring_pos_rel;
     }
 
     // Tabbing: Activates Inputable, otherwise only Focus
-    if ((g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) && (result->InFlags & ImGuiItemFlags_Inputable) == 0)
+    if ((g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing) && (result->InFlags & ImGuiItemFlags_Inputable) == 0)
         g.NavMoveFlags &= ~ImGuiNavMoveFlags_Activate;
 
     // Activate
@@ -12492,7 +12457,7 @@ void ImGui::NavMoveRequestApplyResult()
         g.NavNextActivateId = result->ID;
         g.NavNextActivateFlags = ImGuiActivateFlags_None;
         g.NavMoveFlags |= ImGuiNavMoveFlags_NoSetNavHighlight;
-        if (g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing)
+        if (g.NavMoveFlags & ImGuiNavMoveFlags_IsTabbing)
             g.NavNextActivateFlags |= ImGuiActivateFlags_PreferInput | ImGuiActivateFlags_TryToPreserveState;
     }
 
@@ -12592,14 +12557,14 @@ static float ImGui::NavUpdatePageUpPageDown()
             nav_scoring_rect_offset_y = -page_offset_y;
             g.NavMoveDir = ImGuiDir_Down; // Because our scoring rect is offset up, we request the down direction (so we can always land on the last item)
             g.NavMoveClipDir = ImGuiDir_Up;
-            g.NavMoveFlags = ImGuiNavMoveFlags_AllowCurrentNavId | ImGuiNavMoveFlags_AlsoScoreVisibleSet;
+            g.NavMoveFlags = ImGuiNavMoveFlags_AllowCurrentNavId | ImGuiNavMoveFlags_AlsoScoreVisibleSet | ImGuiNavMoveFlags_IsPageMove;
         }
         else if (IsKeyPressed(ImGuiKey_PageDown, true))
         {
             nav_scoring_rect_offset_y = +page_offset_y;
             g.NavMoveDir = ImGuiDir_Up; // Because our scoring rect is offset down, we request the up direction (so we can always land on the last item)
             g.NavMoveClipDir = ImGuiDir_Down;
-            g.NavMoveFlags = ImGuiNavMoveFlags_AllowCurrentNavId | ImGuiNavMoveFlags_AlsoScoreVisibleSet;
+            g.NavMoveFlags = ImGuiNavMoveFlags_AllowCurrentNavId | ImGuiNavMoveFlags_AlsoScoreVisibleSet | ImGuiNavMoveFlags_IsPageMove;
         }
         else if (home_pressed)
         {
@@ -19441,7 +19406,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     // DrawLists
     int drawlist_count = 0;
     for (int viewport_i = 0; viewport_i < g.Viewports.Size; viewport_i++)
-        drawlist_count += g.Viewports[viewport_i]->DrawDataBuilder.GetDrawListCount();
+        drawlist_count += g.Viewports[viewport_i]->DrawDataP.CmdLists.Size;
     if (TreeNode("DrawLists", "DrawLists (%d)", drawlist_count))
     {
         Checkbox("Show ImDrawCmd mesh when hovering", &cfg->ShowDrawCmdMesh);
@@ -19450,14 +19415,13 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         {
             ImGuiViewportP* viewport = g.Viewports[viewport_i];
             bool viewport_has_drawlist = false;
-            for (int layer_i = 0; layer_i < IM_ARRAYSIZE(viewport->DrawDataBuilder.Layers); layer_i++)
-                for (int draw_list_i = 0; draw_list_i < viewport->DrawDataBuilder.Layers[layer_i].Size; draw_list_i++)
-                {
-                    if (!viewport_has_drawlist)
-                        Text("Active DrawLists in Viewport #%d, ID: 0x%08X", viewport->Idx, viewport->ID);
-                    viewport_has_drawlist = true;
-                    DebugNodeDrawList(NULL, viewport, viewport->DrawDataBuilder.Layers[layer_i][draw_list_i], "DrawList");
-                }
+            for (int draw_list_i = 0; draw_list_i < viewport->DrawDataP.CmdLists.Size; draw_list_i++)
+            {
+                if (!viewport_has_drawlist)
+                    Text("Active DrawLists in Viewport #%d, ID: 0x%08X", viewport->Idx, viewport->ID);
+                viewport_has_drawlist = true;
+                DebugNodeDrawList(NULL, viewport, viewport->DrawDataP.CmdLists[draw_list_i], "DrawList");
+            }
         }
         TreePop();
     }
@@ -20261,9 +20225,8 @@ void ImGui::DebugNodeViewport(ImGuiViewportP* viewport)
             (flags & ImGuiViewportFlags_NoAutoMerge) ? " NoAutoMerge" : "",
             (flags & ImGuiViewportFlags_TopMost) ? " TopMost" : "",
             (flags & ImGuiViewportFlags_CanHostOtherWindows) ? " CanHostOtherWindows" : "");
-        for (int layer_i = 0; layer_i < IM_ARRAYSIZE(viewport->DrawDataBuilder.Layers); layer_i++)
-            for (int draw_list_i = 0; draw_list_i < viewport->DrawDataBuilder.Layers[layer_i].Size; draw_list_i++)
-                DebugNodeDrawList(NULL, viewport, viewport->DrawDataBuilder.Layers[layer_i][draw_list_i], "DrawList");
+        for (int draw_list_i = 0; draw_list_i < viewport->DrawDataP.CmdLists.Size; draw_list_i++)
+            DebugNodeDrawList(NULL, viewport, viewport->DrawDataP.CmdLists[draw_list_i], "DrawList");
         TreePop();
     }
 }

imgui.h

@@ -25,7 +25,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM >= 12345')
 #define IMGUI_VERSION       "1.89.8 WIP"
-#define IMGUI_VERSION_NUM   18972
+#define IMGUI_VERSION_NUM   18973
 #define IMGUI_HAS_TABLE
 #define IMGUI_HAS_VIEWPORT          // Viewport WIP branch
 #define IMGUI_HAS_DOCK              // Docking WIP branch
@@ -2856,19 +2856,20 @@ struct ImDrawList
 // as this is one of the oldest structure exposed by the library! Basically, ImDrawList == CmdList)
 struct ImDrawData
 {
-    bool            Valid;                  // Only valid after Render() is called and before the next NewFrame() is called.
-    int             CmdListsCount;          // Number of ImDrawList* to render
-    int             TotalIdxCount;          // For convenience, sum of all ImDrawList's IdxBuffer.Size
-    int             TotalVtxCount;          // For convenience, sum of all ImDrawList's VtxBuffer.Size
-    ImDrawList**    CmdLists;               // Array of ImDrawList* to render. The ImDrawList are owned by ImGuiContext and only pointed to from here.
-    ImVec2          DisplayPos;             // Top-left position of the viewport to render (== top-left of the orthogonal projection matrix to use) (== GetMainViewport()->Pos for the main viewport, == (0.0) in most single-viewport applications)
-    ImVec2          DisplaySize;            // Size of the viewport to render (== GetMainViewport()->Size for the main viewport, == io.DisplaySize in most single-viewport applications)
-    ImVec2          FramebufferScale;       // Amount of pixels for each unit of DisplaySize. Based on io.DisplayFramebufferScale. Generally (1,1) on normal display, (2,2) on OSX with Retina display.
-    ImGuiViewport*  OwnerViewport;          // Viewport carrying the ImDrawData instance, might be of use to the renderer (generally not).
+    bool                Valid;              // Only valid after Render() is called and before the next NewFrame() is called.
+    int                 CmdListsCount;      // Number of ImDrawList* to render
+    int                 TotalIdxCount;      // For convenience, sum of all ImDrawList's IdxBuffer.Size
+    int                 TotalVtxCount;      // For convenience, sum of all ImDrawList's VtxBuffer.Size
+    ImVector<ImDrawList*> CmdLists;         // Array of ImDrawList* to render. The ImDrawLists are owned by ImGuiContext and only pointed to from here.
+    ImVec2              DisplayPos;         // Top-left position of the viewport to render (== top-left of the orthogonal projection matrix to use) (== GetMainViewport()->Pos for the main viewport, == (0.0) in most single-viewport applications)
+    ImVec2              DisplaySize;        // Size of the viewport to render (== GetMainViewport()->Size for the main viewport, == io.DisplaySize in most single-viewport applications)
+    ImVec2              FramebufferScale;   // Amount of pixels for each unit of DisplaySize. Based on io.DisplayFramebufferScale. Generally (1,1) on normal display, (2,2) on OSX with Retina display.
+    ImGuiViewport*      OwnerViewport;      // Viewport carrying the ImDrawData instance, might be of use to the renderer (generally not).
 
     // Functions
     ImDrawData()    { Clear(); }
-    void Clear()    { memset(this, 0, sizeof(*this)); }     // The ImDrawList are owned by ImGuiContext!
+    IMGUI_API void  Clear();
+    IMGUI_API void  AddDrawList(ImDrawList* draw_list);     // Helper to add an external draw list into an existing ImDrawData.
     IMGUI_API void  DeIndexAllBuffers();                    // Helper to convert all buffers from indexed to non-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
     IMGUI_API void  ScaleClipRects(const ImVec2& fb_scale); // Helper to scale the ClipRect field of each ImDrawCmd. Use if your final output buffer is at a different scale than Dear ImGui expects, or if there is a difference between your window resolution and framebuffer resolution.
 };

imgui_draw.cpp

@@ -1814,6 +1814,63 @@ void ImDrawListSplitter::SetCurrentChannel(ImDrawList* draw_list, int idx)
 // [SECTION] ImDrawData
 //-----------------------------------------------------------------------------
 
+void ImDrawData::Clear()
+{
+    Valid = false;
+    CmdListsCount = TotalIdxCount = TotalVtxCount = 0;
+    CmdLists.resize(0); // The ImDrawList are NOT owned by ImDrawData but e.g. by ImGuiContext, so we don't clear them.
+    DisplayPos = DisplaySize = FramebufferScale = ImVec2(0.0f, 0.0f);
+    OwnerViewport = NULL;
+}
+
+// Important: 'out_list' is generally going to be draw_data->CmdLists, but may be another temporary list
+// as long at it is expected that the result will be later merged into draw_data->CmdLists[].
+void ImGui::AddDrawListToDrawDataEx(ImDrawData* draw_data, ImVector<ImDrawList*>* out_list, ImDrawList* draw_list)
+{
+    if (draw_list->CmdBuffer.Size == 0)
+        return;
+    if (draw_list->CmdBuffer.Size == 1 && draw_list->CmdBuffer[0].ElemCount == 0 && draw_list->CmdBuffer[0].UserCallback == NULL)
+        return;
+
+    // Draw list sanity check. Detect mismatch between PrimReserve() calls and incrementing _VtxCurrentIdx, _VtxWritePtr etc.
+    // May trigger for you if you are using PrimXXX functions incorrectly.
+    IM_ASSERT(draw_list->VtxBuffer.Size == 0 || draw_list->_VtxWritePtr == draw_list->VtxBuffer.Data + draw_list->VtxBuffer.Size);
+    IM_ASSERT(draw_list->IdxBuffer.Size == 0 || draw_list->_IdxWritePtr == draw_list->IdxBuffer.Data + draw_list->IdxBuffer.Size);
+    if (!(draw_list->Flags & ImDrawListFlags_AllowVtxOffset))
+        IM_ASSERT((int)draw_list->_VtxCurrentIdx == draw_list->VtxBuffer.Size);
+
+    // Check that draw_list doesn't use more vertices than indexable (default ImDrawIdx = unsigned short = 2 bytes = 64K vertices per ImDrawList = per window)
+    // If this assert triggers because you are drawing lots of stuff manually:
+    // - First, make sure you are coarse clipping yourself and not trying to draw many things outside visible bounds.
+    //   Be mindful that the lower-level ImDrawList API doesn't filter vertices. Use the Metrics/Debugger window to inspect draw list contents.
+    // - If you want large meshes with more than 64K vertices, you can either:
+    //   (A) Handle the ImDrawCmd::VtxOffset value in your renderer backend, and set 'io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset'.
+    //       Most example backends already support this from 1.71. Pre-1.71 backends won't.
+    //       Some graphics API such as GL ES 1/2 don't have a way to offset the starting vertex so it is not supported for them.
+    //   (B) Or handle 32-bit indices in your renderer backend, and uncomment '#define ImDrawIdx unsigned int' line in imconfig.h.
+    //       Most example backends already support this. For example, the OpenGL example code detect index size at compile-time:
+    //         glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer_offset);
+    //       Your own engine or render API may use different parameters or function calls to specify index sizes.
+    //       2 and 4 bytes indices are generally supported by most graphics API.
+    // - If for some reason neither of those solutions works for you, a workaround is to call BeginChild()/EndChild() before reaching
+    //   the 64K limit to split your draw commands in multiple draw lists.
+    if (sizeof(ImDrawIdx) == 2)
+        IM_ASSERT(draw_list->_VtxCurrentIdx < (1 << 16) && "Too many vertices in ImDrawList using 16-bit indices. Read comment above");
+
+    // Add to output list + records state in ImDrawData
+    out_list->push_back(draw_list);
+    draw_list->_PopUnusedDrawCmd();
+    draw_data->CmdListsCount++;
+    draw_data->TotalVtxCount += draw_list->VtxBuffer.Size;
+    draw_data->TotalIdxCount += draw_list->IdxBuffer.Size;
+}
+
+void ImDrawData::AddDrawList(ImDrawList* draw_list)
+{
+    IM_ASSERT(CmdLists.Size == CmdListsCount);
+    ImGui::AddDrawListToDrawDataEx(this, &CmdLists, draw_list);
+}
+
 // For backward compatibility: convert all buffers from indexed to de-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
 void ImDrawData::DeIndexAllBuffers()
 {

imgui_internal.h

@@ -782,12 +782,10 @@ struct IMGUI_API ImDrawListSharedData
 
 struct ImDrawDataBuilder
 {
-    ImVector<ImDrawList*>   Layers[2];           // Global layers for: regular, tooltip
+    ImVector<ImDrawList*>*  Layers[2];      // Pointers to global layers for: regular, tooltip. LayersP[0] is owned by DrawData.
+    ImVector<ImDrawList*>   LayerData1;
 
-    void Clear()                    { for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n].resize(0); }
-    void ClearFreeMemory()          { for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n].clear(); }
-    int  GetDrawListCount() const   { int count = 0; for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) count += Layers[n].Size; return count; }
-    IMGUI_API void FlattenIntoSingleLayer();
+    ImDrawDataBuilder()                     { memset(this, 0, sizeof(*this)); }
 };
 
 //-----------------------------------------------------------------------------
@@ -1514,10 +1512,11 @@ enum ImGuiNavMoveFlags_
     ImGuiNavMoveFlags_Forwarded             = 1 << 7,
     ImGuiNavMoveFlags_DebugNoResult         = 1 << 8,   // Dummy scoring for debug purpose, don't apply result
     ImGuiNavMoveFlags_FocusApi              = 1 << 9,   // Requests from focus API can land/focus/activate items even if they are marked with _NoTabStop (see NavProcessItemForTabbingRequest() for details)
-    ImGuiNavMoveFlags_Tabbing               = 1 << 10,  // == Focus + Activate if item is Inputable + DontChangeNavHighlight
-    ImGuiNavMoveFlags_Activate              = 1 << 11,  // Activate/select target item.
-    ImGuiNavMoveFlags_NoSelect              = 1 << 12,  // Don't trigger selection by not setting g.NavJustMovedTo
-    ImGuiNavMoveFlags_NoSetNavHighlight     = 1 << 13,  // Do not alter the visible state of keyboard vs mouse nav highlight
+    ImGuiNavMoveFlags_IsTabbing             = 1 << 10,  // == Focus + Activate if item is Inputable + DontChangeNavHighlight
+    ImGuiNavMoveFlags_IsPageMove            = 1 << 11,  // Identify a PageDown/PageUp request.
+    ImGuiNavMoveFlags_Activate              = 1 << 12,  // Activate/select target item.
+    ImGuiNavMoveFlags_NoSelect              = 1 << 13,  // Don't trigger selection by not setting g.NavJustMovedTo
+    ImGuiNavMoveFlags_NoSetNavHighlight     = 1 << 14,  // Do not alter the visible state of keyboard vs mouse nav highlight
 };
 
 enum ImGuiNavLayer
@@ -1772,7 +1771,7 @@ struct ImGuiViewportP : public ImGuiViewport
     int                 DrawListsLastFrame[2];  // Last frame number the background (0) and foreground (1) draw lists were used
     ImDrawList*         DrawLists[2];           // Convenience background (0) and foreground (1) draw lists. We use them to draw software mouser cursor when io.MouseDrawCursor is set and to draw most debug overlays.
     ImDrawData          DrawDataP;
-    ImDrawDataBuilder   DrawDataBuilder;
+    ImDrawDataBuilder   DrawDataBuilder;        // Temporary data while building final ImDrawData
     ImVec2              LastPlatformPos;
     ImVec2              LastPlatformSize;
     ImVec2              LastRendererSize;
@@ -3038,6 +3037,7 @@ namespace ImGui
     IMGUI_API void          SetCurrentFont(ImFont* font);
     inline ImFont*          GetDefaultFont() { ImGuiContext& g = *GImGui; return g.IO.FontDefault ? g.IO.FontDefault : g.IO.Fonts->Fonts[0]; }
     inline ImDrawList*      GetForegroundDrawList(ImGuiWindow* window) { return GetForegroundDrawList(window->Viewport); }
+    IMGUI_API void          AddDrawListToDrawDataEx(ImDrawData* draw_data, ImVector<ImDrawList*>* out_list, ImDrawList* draw_list);
 
     // Init
     IMGUI_API void          Initialize();