Docking: Comments + maiintain LastFrameFocused per node + using bitfiield for docking bools.

docs/TODO.txt

@@ -133,7 +133,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - dock: B- single visible node part of a hidden split hierarchy (OnlyNodeWithWindows != NULL) should show a normal title bar (not a tab bar)
  - dock: B~ SetNextWindowDock() calls (with conditional) -> defer everything to DockContextUpdate (repro: Documents->[X]Windows->Dock 1 elsewhere->Click Redock All
  - dock: B~ tidy up tab list popup buttons features (available with manual tab-bar, see ImGuiTabBarFlags_NoTabListPopupButton code, not used by docking nodes)
- - dock: B- DockSpace() border issues
+ - dock: B- SetNextWindowDockId(0) with a second Begin() in the frame will asserts
  - dock: B- inconsistent clipping/border 1-pixel issue (#2)
  - dock: B- fix/disable auto-resize grip on split host nodes (~#2)
  - dock: B- SetNextWindowFocus() doesn't seem to apply if the window is hidden this frame, need repro (#4)

imgui.cpp

@@ -10351,7 +10351,7 @@ ImGuiDockNode::ImGuiDockNode(ImGuiID id)
 
     HostWindow = VisibleWindow = NULL;
     CentralNode = OnlyNodeWithWindows = NULL;
-    LastFrameAlive = LastFrameActive = -1;
+    LastFrameAlive = LastFrameActive = LastFrameFocused = -1;
     LastFocusedNodeID = 0;
     SelectedTabID = 0;
     WantCloseTabID = 0;
@@ -10568,7 +10568,7 @@ struct ImGuiDockNodeUpdateScanResults
     ImGuiDockNode*      CentralNode;
     ImGuiDockNode*      FirstNodeWithWindows;
     int                 CountNodesWithWindows;
-    ImGuiDockFamily DockFamilyForMerges;
+    //ImGuiDockFamily   DockFamilyForMerges;
 
     ImGuiDockNodeUpdateScanResults() { CentralNode = FirstNodeWithWindows = NULL; CountNodesWithWindows = 0; }
 };
@@ -10594,6 +10594,8 @@ static void DockNodeUpdateScanRec(ImGuiDockNode* node, ImGuiDockNodeUpdateScanRe
         DockNodeUpdateScanRec(node->ChildNodes[1], results);
 }
 
+// - Remove inactive windows/nodes.
+// - Update visibility flag.
 static void ImGui::DockNodeUpdateVisibleFlagAndInactiveChilds(ImGuiDockNode* node)
 {
     ImGuiContext& g = *GImGui;
@@ -10679,7 +10681,9 @@ static void ImGui::DockNodeUpdate(ImGuiDockNode* node)
     {
         DockNodeUpdateVisibleFlagAndInactiveChilds(node);
 
-        // Find if there's only a single visible window in the hierarchy (in which case we need to display a regular title bar -> FIXME-DOCK: that last part is not done yet!)
+        // FIXME-DOCK: Merge this scan into the one above.
+        // - Setup central node pointers
+        // - Find if there's only a single visible window in the hierarchy (in which case we need to display a regular title bar -> FIXME-DOCK: that last part is not done yet!)
         ImGuiDockNodeUpdateScanResults results;
         DockNodeUpdateScanRec(node, &results);
         node->CentralNode = results.CentralNode;
@@ -10756,7 +10760,7 @@ static void ImGui::DockNodeUpdate(ImGuiDockNode* node)
         node->HasCollapseButton = (node->Windows.Size > 0);
         for (int window_n = 0; window_n < node->Windows.Size; window_n++)
         {
-            // FIXME: Setting DockIsActive here means that for single active window in a leaf node, DockIsActive will be cleared until the next Begin() call.
+            // FIXME-DOCK: Setting DockIsActive here means that for single active window in a leaf node, DockIsActive will be cleared until the next Begin() call.
             ImGuiWindow* window = node->Windows[window_n];
             window->DockIsActive = (node->Windows.Size > 1);
             node->HasCloseButton |= window->HasCloseButton;
@@ -10938,6 +10942,8 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
     {
         node->VisibleWindow = (node->Windows.Size > 0) ? node->Windows[0] : NULL;
         node->IsFocused = is_focused;
+        if (is_focused)
+            node->LastFrameFocused = g.FrameCount;
 
         // Notify root of visible window (used to display title in OS task bar)
         if (node->VisibleWindow)
@@ -10997,6 +11003,8 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
 
     // Title bar
     node->IsFocused = is_focused;
+    if (is_focused)
+        node->LastFrameFocused = g.FrameCount;
     ImRect title_bar_rect = ImRect(node->Pos, node->Pos + ImVec2(node->Size.x, g.FontSize + style.FramePadding.y * 2.0f));
     ImU32 title_bar_col = GetColorU32(host_window->Collapsed ? ImGuiCol_TitleBgCollapsed : is_focused ? ImGuiCol_TitleBgActive : ImGuiCol_TitleBg);
     host_window->DrawList->AddRectFilled(title_bar_rect.Min, title_bar_rect.Max, title_bar_col, host_window->WindowRounding, ImDrawCornerFlags_Top);
@@ -11850,15 +11858,15 @@ ImGuiID ImGui::DockSpaceOverViewport(ImGuiViewport* viewport, ImGuiDockNodeFlags
     char label[32];
     ImFormatString(label, IM_ARRAYSIZE(label), "DockspaceViewport_%08X", viewport->ID);
 
-    ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
-    ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
-    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
-    ImGui::Begin(label, NULL, host_window_flags);
-    ImGui::PopStyleVar(3);
+    PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
+    PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
+    PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
+    Begin(label, NULL, host_window_flags);
+    PopStyleVar(3);
 
-    ImGuiID dockspace_id = ImGui::GetID("Dockspace");
-    ImGui::DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags, dock_family);
-    ImGui::End();
+    ImGuiID dockspace_id = GetID("Dockspace");
+    DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags, dock_family);
+    End();
 
     return dockspace_id;
 }

imgui_internal.h

@@ -752,7 +752,7 @@ struct ImGuiTabBarSortItem
     float       Width;
 };
 
-// sizeof() 108~144
+// sizeof() 116~160
 struct ImGuiDockNode
 {
     ImGuiID                 ID;
@@ -773,6 +773,7 @@ struct ImGuiDockNode
     ImGuiDockNode*          OnlyNodeWithWindows;        // [Root node only] Set when there is a single visible node within the hierarchy.
     int                     LastFrameAlive;             // Last frame number the node was updated or kept alive explicitly with DockSpace() + ImGuiDockNodeFlags_KeepAliveOnly
     int                     LastFrameActive;            // Last frame number the node was updated.
+    int                     LastFrameFocused;           // Last frame number the node was focused.
     ImGuiID                 LastFocusedNodeID;          // [Root node only] Which of our child node (any ancestor in the hierarchy) was last focused.
     ImGuiID                 SelectedTabID;              // [Tab node only] Which of our tab is selected.
     ImGuiID                 WantCloseTabID;             // [Tab node only] Set when closing a specific tab.
@@ -1274,9 +1275,9 @@ struct IMGUI_API ImGuiWindow
     ImGuiItemStatusFlags    DockTabItemStatusFlags;
     ImRect                  DockTabItemRect;
     short                   DockOrder;                          // Order of the last time the window was visible within its DockNode. This is used to reorder windows that are reappearing on the same frame. Same value between windows that were active and windows that were none are possible.
-    bool                    DockIsActive;                       // =~ (DockNode != NULL) && (DockNode->Windows.Size > 1)
-    bool                    DockTabIsVisible;                   // Is the window visible this frame? =~ is the corresponding tab selected?
-    bool                    DockTabWantClose;
+    bool                    DockIsActive        :1;             // =~ (DockNode != NULL) && (DockNode->Windows.Size > 1)
+    bool                    DockTabIsVisible    :1;             // Is the window visible this frame? =~ is the corresponding tab selected?
+    bool                    DockTabWantClose    :1;
 
 public:
     ImGuiWindow(ImGuiContext* context, const char* name);