Docking: Renamed io.ConfigDockingTabBarOnSingleWindows to io.ConfigDockingAlwaysTabBar. (#2109)

Added ImGuiWindowClass::DockingAlwaysTabBar to set on individual windows.

docs/CHANGELOG.txt

@@ -38,15 +38,16 @@ DOCKING FEATURES
 - Added Docking system: [BETA] (#2109, #351)
   - Added ImGuiConfigFlags_DockingEnable flag to enable Docking.
     Set with `io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;`.
-  - Added DockSpace() API.
+  - Added DockSpace(), DockSpaceOverViewport() API.
   - Added ImGuiDockNodeFlags flags for DockSpace().
-  - Added SetNextWindowDock(), SetNextWindowClass() API.
-  - Added GetWindowDockId(), IsWindowDocked() API.
+  - Added SetNextWindowDockID(), SetNextWindowClass() API.
+  - Added GetWindowDockID(), IsWindowDocked() API.
   - Added ImGuiWindowFlags_NoDocking window flag to disable the possibility for a window to be docked.
     Popup, Menu and Child windows always have the ImGuiWindowFlags_NoDocking flag set.
+  - Added ImGuiWindowClass to specify advanced docking/viewport related flags via SetNextWindowClass().
   - Added io.ConfigDockingNoSplit option.
   - Added io.ConfigDockingWithShift option.
-  - Added io.ConfigDockingTabBarOnSingleWindows option.
+  - Added io.ConfigDockingAlwaysTabBar option.
   - Added io.ConfigDockingTransparentPayload option.
   - Style: Added ImGuiCol_DockingPreview, ImGuiCol_DockingEmptyBg colors.
   - Demo: Added "DockSpace" example app showcasing use of explicit dockspace nodes.

examples/example_win32_directx11/main.cpp

@@ -55,7 +55,7 @@ int main(int, char**)
     //io.ConfigViewportsNoAutoMerge = true;
     //io.ConfigViewportsNoTaskBarIcon = true;
     //io.ConfigViewportsNoDefaultParent = true;
-    //io.ConfigDockingTabBarOnSingleWindows = true;
+    //io.ConfigDockingAlwaysTabBar = true;
     //io.ConfigDockingTransparentPayload = true;
 #if 1
     io.ConfigFlags |= ImGuiConfigFlags_DpiEnableScaleFonts;     // FIXME-DPI: THIS CURRENTLY DOESN'T WORK AS EXPECTED. DON'T USE IN USER APP!

imgui.cpp

@@ -1262,7 +1262,7 @@ ImGuiIO::ImGuiIO()
     // Docking options (when ImGuiConfigFlags_DockingEnable is set)
     ConfigDockingNoSplit = false;
     ConfigDockingWithShift = false;
-    ConfigDockingTabBarOnSingleWindows = false;
+    ConfigDockingAlwaysTabBar = false;
     ConfigDockingTransparentPayload = false;
 
     // Viewport options (when ImGuiConfigFlags_ViewportsEnable is set)
@@ -2731,6 +2731,7 @@ ImGuiWindow::ImGuiWindow(ImGuiContext* context, const char* name)
     SkipItems = false;
     Appearing = false;
     Hidden = false;
+    FallbackWindow = false;
     HasCloseButton = false;
     ResizeBorderHeld = -1;
     BeginCount = 0;
@@ -4034,7 +4035,8 @@ void ImGui::NewFrame()
     // This fallback is particularly important as it avoid ImGui:: calls from crashing.
     SetNextWindowSize(ImVec2(400,400), ImGuiCond_FirstUseEver);
     Begin("Debug##Default");
-    g.FrameScopePushedImplicitWindow = true;
+    IM_ASSERT(g.CurrentWindow->FallbackWindow == true);
+    g.FrameScopePushedFallbackWindow = true;
 
 #ifdef IMGUI_ENABLE_TEST_ENGINE
     ImGuiTestEngineHook_PostNewFrame(&g);
@@ -4407,7 +4409,7 @@ void ImGui::EndFrame()
     }
 
     // Hide implicit/fallback "Debug" window if it hasn't been used
-    g.FrameScopePushedImplicitWindow = false;
+    g.FrameScopePushedFallbackWindow = false;
     if (g.CurrentWindow && !g.CurrentWindow->WriteAccessed)
         g.CurrentWindow->Active = false;
     End();
@@ -5760,7 +5762,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     // Find or create
     ImGuiWindow* window = FindWindowByName(name);
     const bool window_just_created = (window == NULL);
-    const bool window_is_fallback = (g.CurrentWindowStack.Size == 0);
     if (window_just_created)
     {
         ImVec2 size_on_first_use = (g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasSize) ? g.NextWindowData.SizeVal : ImVec2(0.0f, 0.0f); // Any condition flag will do since we are creating a new window here.
@@ -5776,6 +5777,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
     const int current_frame = g.FrameCount;
     const bool first_begin_of_the_frame = (window->LastFrameActive != current_frame);
+    window->FallbackWindow = (g.CurrentWindowStack.Size == 0);
 
     // Update the Appearing flag
     bool window_just_activated_by_user = (window->LastFrameActive < current_frame - 1);   // Not using !WasActive because the implicit "Debug" window would always toggle off->on
@@ -5812,7 +5814,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     if (first_begin_of_the_frame)
     {
         bool has_dock_node = (window->DockId != 0 || window->DockNode != NULL);
-        bool new_auto_dock_node = !has_dock_node && g.IO.ConfigDockingTabBarOnSingleWindows && !(flags & (ImGuiWindowFlags_ChildWindow | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoDocking)) && !window_is_fallback;
+        bool new_auto_dock_node = !has_dock_node && GetWindowAlwaysWantOwnTabBar(window);
         if (has_dock_node || new_auto_dock_node)
         {
             BeginDocked(window, p_open);
@@ -6556,7 +6558,7 @@ void ImGui::End()
 {
     ImGuiContext& g = *GImGui;
 
-    if (g.CurrentWindowStack.Size <= 1 && g.FrameScopePushedImplicitWindow)
+    if (g.CurrentWindowStack.Size <= 1 && g.FrameScopePushedFallbackWindow)
     {
         IM_ASSERT(g.CurrentWindowStack.Size > 1 && "Calling End() too many times!");
         return; // FIXME-ERRORHANDLING
@@ -12026,7 +12028,11 @@ static void ImGui::DockNodeUpdate(ImGuiDockNode* node)
         DockNodeRemoveTabBar(node);
 
     // Early out for hidden root dock nodes (when all DockId references are in inactive windows, or there is only 1 floating window holding on the DockId)
-    if (node->Windows.Size <= 1 && node->IsFloatingNode() && node->IsLeafNode() && !g.IO.ConfigDockingTabBarOnSingleWindows)
+    bool want_to_hide_host_window = false;
+    if (node->Windows.Size <= 1 && node->IsFloatingNode() && node->IsLeafNode())
+        if (!g.IO.ConfigDockingAlwaysTabBar && (node->Windows.Size == 0 || !node->Windows[0]->WindowClass.DockingAlwaysTabBar))
+            want_to_hide_host_window = true;
+    if (want_to_hide_host_window)
     {
         if (node->Windows.Size == 1)
         {
@@ -13749,12 +13755,22 @@ void ImGui::DockBuilderFinish(ImGuiID root_id)
 // Docking: Begin/End Functions (called from Begin/End)
 //-----------------------------------------------------------------------------
 
+bool ImGui::GetWindowAlwaysWantOwnTabBar(ImGuiWindow* window)
+{
+    ImGuiContext& g = *GImGui;
+    if (g.IO.ConfigDockingAlwaysTabBar || window->WindowClass.DockingAlwaysTabBar)
+        if ((window->Flags & (ImGuiWindowFlags_ChildWindow | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoDocking)) == 0)
+            if (!window->FallbackWindow)    // We don't support AlwaysTabBar on the fallback/implicit window to avoid unused dock-node overhead/noise
+                return true;
+    return false;
+}
+
 void ImGui::BeginDocked(ImGuiWindow* window, bool* p_open)
 {
     ImGuiContext* ctx = GImGui;
     ImGuiContext& g = *ctx;
 
-    const bool auto_dock_node = (g.IO.ConfigDockingTabBarOnSingleWindows) && !(window->Flags & (ImGuiWindowFlags_ChildWindow | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoDocking));
+    const bool auto_dock_node = GetWindowAlwaysWantOwnTabBar(window);
     if (auto_dock_node)
     {
         if (window->DockId == 0)

imgui.h

@@ -1425,7 +1425,7 @@ struct ImGuiIO
     // Docking options (when ImGuiConfigFlags_DockingEnable is set)
     bool        ConfigDockingNoSplit;           // = false          // Simplified docking mode: disable window splitting, so docking is limited to merging multiple windows together into tab-bars.
     bool        ConfigDockingWithShift;         // = false          // Enable docking with holding Shift key (reduce visual noise, allows dropping in wider space)
-    bool        ConfigDockingTabBarOnSingleWindows; // = false      // [BETA] Make every single floating window display within a docking node.
+    bool        ConfigDockingAlwaysTabBar;      // = false          // [BETA] [FIXME: This currently creates regression with auto-sizing and general overhead] Make every single floating window display within a docking node.
     bool        ConfigDockingTransparentPayload;// = false          // [BETA] Make window or viewport transparent when docking and only display docking boxes on the target viewport. Useful if rendering of multiple viewport cannot be synced. Best used with ConfigViewportsNoAutoMerge.
     
     // Viewport options (when ImGuiConfigFlags_ViewportsEnable is set)
@@ -1612,9 +1612,10 @@ struct ImGuiWindowClass
     ImGuiID             ParentViewportId;           // Hint for the platform back-end. If non-zero, the platform back-end can create a parent<>child relationship between the platform windows. Not conforming back-ends are free to e.g. parent every viewport to the main viewport or not.
     ImGuiViewportFlags  ViewportFlagsOverrideMask;  // Viewport flags to override when a window of this class owns a viewport. This allows you to enforce OS decoration or task bar icon, override the defaults on a per-window basis.
     ImGuiViewportFlags  ViewportFlagsOverrideValue; // Viewport flags values to override when a window of this class owns a viewport.
+    bool                DockingAlwaysTabBar;        // Set to true to enforce windows of this class always having their own tab (equivalent of setting the global io.ConfigDockingAlwaysTabBar)
     bool                DockingAllowUnclassed;      // Set to true to allow windows of this class to be docked/merged with an unclassed window.
 
-    ImGuiWindowClass()  { ClassId = 0; ParentViewportId = 0; ViewportFlagsOverrideMask = ViewportFlagsOverrideValue = 0x00; DockingAllowUnclassed = true; }
+    ImGuiWindowClass()  { ClassId = 0; ParentViewportId = 0; ViewportFlagsOverrideMask = ViewportFlagsOverrideValue = 0x00; DockingAlwaysTabBar = false; DockingAllowUnclassed = true; }
 };
 
 //-----------------------------------------------------------------------------

imgui_demo.cpp

@@ -368,7 +368,7 @@ void ImGui::ShowDemoWindow(bool* p_open)
                 ImGui::SameLine(); HelpMarker("Simplified docking mode: disable window splitting, so docking is limited to merging multiple windows together into tab-bars.");
                 ImGui::Checkbox("io.ConfigDockingWithShift", &io.ConfigDockingWithShift);
                 ImGui::SameLine(); HelpMarker("Enable docking when holding Shift only (allows to drop in wider space, reduce visual noise)");
-                ImGui::Checkbox("io.ConfigDockingTabBarOnSingleWindows", &io.ConfigDockingTabBarOnSingleWindows);
+                ImGui::Checkbox("io.ConfigDockingAlwaysTabBar", &io.ConfigDockingAlwaysTabBar);
                 ImGui::SameLine(); HelpMarker("Create a docking node and tab-bar on single floating windows.");
                 ImGui::Checkbox("io.ConfigDockingTransparentPayload", &io.ConfigDockingTransparentPayload);
                 ImGui::SameLine(); HelpMarker("Make window or viewport transparent when docking and only display docking boxes on the target viewport. Useful if rendering of multiple viewport cannot be synced. Best used with ConfigViewportsNoAutoMerge.");
@@ -3079,7 +3079,7 @@ void ImGui::ShowAboutWindow(bool* p_open)
         if (io.ConfigViewportsNoDefaultParent)                          ImGui::Text("io.ConfigViewportsNoDefaultParent");
         if (io.ConfigDockingNoSplit)                                    ImGui::Text("io.ConfigDockingNoSplit");
         if (io.ConfigDockingWithShift)                                  ImGui::Text("io.ConfigDockingWithShift");
-        if (io.ConfigDockingTabBarOnSingleWindows)                      ImGui::Text("io.ConfigDockingTabBarOnSingleWindows");
+        if (io.ConfigDockingAlwaysTabBar)                               ImGui::Text("io.ConfigDockingAlwaysTabBar");
         if (io.ConfigDockingTransparentPayload)                         ImGui::Text("io.ConfigDockingTransparentPayload");
         if (io.ConfigMacOSXBehaviors)                                   ImGui::Text("io.ConfigMacOSXBehaviors");
         if (io.ConfigInputTextCursorBlink)                              ImGui::Text("io.ConfigInputTextCursorBlink");

imgui_internal.h

@@ -982,7 +982,7 @@ struct ImGuiContext
 {
     bool                    Initialized;
     bool                    FrameScopeActive;                   // Set by NewFrame(), cleared by EndFrame()
-    bool                    FrameScopePushedImplicitWindow;     // Set by NewFrame(), cleared by EndFrame()
+    bool                    FrameScopePushedFallbackWindow;     // Set by NewFrame(), cleared by EndFrame()
     bool                    FontAtlasOwnedByContext;            // Io.Fonts-> is owned by the ImGuiContext and will be destructed along with it.
     ImGuiIO                 IO;
     ImGuiPlatformIO         PlatformIO;
@@ -1195,7 +1195,7 @@ struct ImGuiContext
     ImGuiContext(ImFontAtlas* shared_font_atlas)
     {
         Initialized = false;
-        FrameScopeActive = FrameScopePushedImplicitWindow = false;
+        FrameScopeActive = FrameScopePushedFallbackWindow = false;
         ConfigFlagsForFrame = ImGuiConfigFlags_None;
         Font = NULL;
         FontSize = FontBaseSize = 0.0f;
@@ -1449,6 +1449,7 @@ struct IMGUI_API ImGuiWindow
     bool                    SkipItems;                          // Set when items can safely be all clipped (e.g. window not visible or collapsed)
     bool                    Appearing;                          // Set during the frame where the window is appearing (or re-appearing)
     bool                    Hidden;                             // Do not display (== (HiddenFrames*** > 0))
+    bool                    FallbackWindow;
     bool                    HasCloseButton;                     // Set when the window has a close button (p_open != NULL)
     signed char             ResizeBorderHeld;                   // Current border being held for resize (-1: none, otherwise 0-3)
     short                   BeginCount;                         // Number of Begin() during the current frame (generally 0 or 1, 1+ if appending via multiple Begin/End pairs)
@@ -1758,6 +1759,7 @@ namespace ImGui
     IMGUI_API void          DockContextQueueUndockNode(ImGuiContext* ctx, ImGuiDockNode* node);
     IMGUI_API bool          DockContextCalcDropPosForDocking(ImGuiWindow* target, ImGuiDockNode* target_node, ImGuiWindow* payload, ImGuiDir split_dir, bool split_outer, ImVec2* out_pos);
     inline ImGuiDockNode*   DockNodeGetRootNode(ImGuiDockNode* node) { while (node->ParentNode) node = node->ParentNode; return node; }
+    IMGUI_API bool          GetWindowAlwaysWantOwnTabBar(ImGuiWindow* window);
     IMGUI_API void          BeginDocked(ImGuiWindow* window, bool* p_open);
     IMGUI_API void          BeginAsDockableDragDropSource(ImGuiWindow* window);
     IMGUI_API void          BeginAsDockableDragDropTarget(ImGuiWindow* window);