Fixed ImGuiWindowFlags_UnsavedDocument clipping label in docked windows with no close button. [changes for docking] (#5745)

+ TabBar: starts displaying the unsaved document marker with a frame delay to match how close button is processed, otherwise the transition would be noticeable.

docs/CHANGELOG.txt

@@ -952,6 +952,8 @@ Docking+Viewports Branch:
   (#4292, #3834, #3633, #3521, #3492, #3335, #2999, #2648)
 - Docking: (Internal/Experimental) Removed DockNodeFlagsOverrideClear flags from ImGuiWindowClass as
   it is ambiguous how to apply them and we haven't got a use out of them yet.
+- Docking: Fixed ImGuiWindowFlags_UnsavedDocument clipping label in docked windows when there are
+  no close button. (#5745)
 - Viewports: Fix popup/tooltip created without a parent window from being given a ParentViewportId value
   from the implicit/fallback window. (#4236, #2409)
 - Backends: Vulkan: Fix the use of the incorrect fence for secondary viewports. (#4208) [@FunMiles]

imgui.cpp

@@ -16158,11 +16158,11 @@ static void ImGui::DockNodePreviewDockRender(ImGuiWindow* host_window, ImGuiDock
             if (!host_node->IsHiddenTabBar() && !host_node->IsNoTabBar())
                 tab_pos.x += host_node->TabBar->WidthAllTabs + g.Style.ItemInnerSpacing.x; // We don't use OffsetNewTab because when using non-persistent-order tab bar it is incremented with each Tab submission.
             else
-                tab_pos.x += g.Style.ItemInnerSpacing.x + TabItemCalcSize(host_node->Windows[0]->Name, host_node->Windows[0]->HasCloseButton).x;
+                tab_pos.x += g.Style.ItemInnerSpacing.x + TabItemCalcSize(host_node->Windows[0]).x;
         }
         else if (!(host_window->Flags & ImGuiWindowFlags_DockNodeHost))
         {
-            tab_pos.x += g.Style.ItemInnerSpacing.x + TabItemCalcSize(host_window->Name, host_window->HasCloseButton).x; // Account for slight offset which will be added when changing from title bar to tab bar
+            tab_pos.x += g.Style.ItemInnerSpacing.x + TabItemCalcSize(host_window).x; // Account for slight offset which will be added when changing from title bar to tab bar
         }
 
         // Draw tab shape/label preview (payload may be a loose window or a host window carrying multiple tabbed windows)
@@ -16180,7 +16180,7 @@ static void ImGui::DockNodePreviewDockRender(ImGuiWindow* host_window, ImGuiDock
                 continue;
 
             // Calculate the tab bounding box for each payload window
-            ImVec2 tab_size = TabItemCalcSize(payload_window->Name, payload_window->HasCloseButton);
+            ImVec2 tab_size = TabItemCalcSize(payload_window);
             ImRect tab_bb(tab_pos.x, tab_pos.y, tab_pos.x + tab_size.x, tab_pos.y + tab_size.y);
             tab_pos.x += tab_size.x + g.Style.ItemInnerSpacing.x;
             const ImU32 overlay_col_text = GetColorU32(payload_window->DockStyle.Colors[ImGuiWindowDockStyleCol_Text]);

imgui_internal.h

@@ -3118,7 +3118,8 @@ namespace ImGui
     IMGUI_API void          TabBarQueueReorderFromMousePos(ImGuiTabBar* tab_bar, const ImGuiTabItem* tab, ImVec2 mouse_pos);
     IMGUI_API bool          TabBarProcessReorder(ImGuiTabBar* tab_bar);
     IMGUI_API bool          TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open, ImGuiTabItemFlags flags, ImGuiWindow* docked_window);
-    IMGUI_API ImVec2        TabItemCalcSize(const char* label, bool has_close_button);
+    IMGUI_API ImVec2        TabItemCalcSize(const char* label, bool has_close_button_or_unsaved_marker);
+    IMGUI_API ImVec2        TabItemCalcSize(ImGuiWindow* window);
     IMGUI_API void          TabItemBackground(ImDrawList* draw_list, const ImRect& bb, ImGuiTabItemFlags flags, ImU32 col);
     IMGUI_API void          TabItemLabelAndCloseButton(ImDrawList* draw_list, const ImRect& bb, ImGuiTabItemFlags flags, ImVec2 frame_padding, const char* label, ImGuiID tab_id, ImGuiID close_button_id, bool is_contents_visible, bool* out_just_closed, bool* out_text_clipped);
 

imgui_widgets.cpp

@@ -7599,8 +7599,8 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
         // Additionally, when using TabBarAddTab() to manipulate tab bar order we occasionally insert new tabs that don't have a width yet,
         // and we cannot wait for the next BeginTabItem() call. We cannot compute this width within TabBarAddTab() because font size depends on the active window.
         const char* tab_name = tab_bar->GetTabName(tab);
-        const bool has_close_button = (tab->Flags & ImGuiTabItemFlags_NoCloseButton) ? false : true;
-        tab->ContentWidth = (tab->RequestedWidth >= 0.0f) ? tab->RequestedWidth : TabItemCalcSize(tab_name, has_close_button).x;
+        const bool has_close_button_or_unsaved_marker = (tab->Flags & ImGuiTabItemFlags_NoCloseButton) == 0 || (tab->Flags & ImGuiTabItemFlags_UnsavedDocument);
+        tab->ContentWidth = (tab->RequestedWidth >= 0.0f) ? tab->RequestedWidth : TabItemCalcSize(tab_name, has_close_button_or_unsaved_marker).x;
 
         int section_n = TabItemGetSectionIdx(tab);
         ImGuiTabBarSection* section = &sections[section_n];
@@ -8168,7 +8168,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     tab_bar->LastTabItemIdx = (ImS16)tab_bar->Tabs.index_from_ptr(tab);
 
     // Calculate tab contents size
-    ImVec2 size = TabItemCalcSize(label, p_open != NULL);
+    ImVec2 size = TabItemCalcSize(label, (p_open != NULL) || (flags & ImGuiTabItemFlags_UnsavedDocument));
     tab->RequestedWidth = -1.0f;
     if (g.NextItemData.Flags & ImGuiNextItemDataFlags_HasWidth)
         size.x = tab->RequestedWidth = g.NextItemData.Width;
@@ -8180,6 +8180,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     const bool tab_bar_appearing = (tab_bar->PrevFrameVisible + 1 < g.FrameCount);
     const bool tab_bar_focused = (tab_bar->Flags & ImGuiTabBarFlags_IsFocused) != 0;
     const bool tab_appearing = (tab->LastFrameVisible + 1 < g.FrameCount);
+    const bool tab_just_unsaved = (flags & ImGuiTabItemFlags_UnsavedDocument) && !(tab->Flags & ImGuiTabItemFlags_UnsavedDocument);
     const bool is_tab_button = (flags & ImGuiTabItemFlags_Button) != 0;
     tab->LastFrameVisible = g.FrameCount;
     tab->Flags = flags;
@@ -8374,7 +8375,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     const ImGuiID close_button_id = p_open ? GetIDWithSeed("#CLOSE", NULL, docked_window ? docked_window->ID : id) : 0;
     bool just_closed;
     bool text_clipped;
-    TabItemLabelAndCloseButton(display_draw_list, bb, flags, tab_bar->FramePadding, label, id, close_button_id, tab_contents_visible, &just_closed, &text_clipped);
+    TabItemLabelAndCloseButton(display_draw_list, bb, tab_just_unsaved ? (flags & ~ImGuiTabItemFlags_UnsavedDocument) : flags, tab_bar->FramePadding, label, id, close_button_id, tab_contents_visible, &just_closed, &text_clipped);
     if (just_closed && p_open != NULL)
     {
         *p_open = false;
@@ -8433,18 +8434,23 @@ void    ImGui::SetTabItemClosed(const char* label)
     }
 }
 
-ImVec2 ImGui::TabItemCalcSize(const char* label, bool has_close_button)
+ImVec2 ImGui::TabItemCalcSize(const char* label, bool has_close_button_or_unsaved_marker)
 {
     ImGuiContext& g = *GImGui;
     ImVec2 label_size = CalcTextSize(label, NULL, true);
     ImVec2 size = ImVec2(label_size.x + g.Style.FramePadding.x, label_size.y + g.Style.FramePadding.y * 2.0f);
-    if (has_close_button)
+    if (has_close_button_or_unsaved_marker)
         size.x += g.Style.FramePadding.x + (g.Style.ItemInnerSpacing.x + g.FontSize); // We use Y intentionally to fit the close button circle.
     else
         size.x += g.Style.FramePadding.x + 1.0f;
     return ImVec2(ImMin(size.x, TabBarCalcMaxTabWidth()), size.y);
 }
 
+ImVec2 ImGui::TabItemCalcSize(ImGuiWindow* window)
+{
+    return TabItemCalcSize(window->Name, window->HasCloseButton || (window->Flags & ImGuiWindowFlags_UnsavedDocument));
+}
+
 void ImGui::TabItemBackground(ImDrawList* draw_list, const ImRect& bb, ImGuiTabItemFlags flags, ImU32 col)
 {
     // While rendering tabs, we trim 1 pixel off the top of our bounding box so they can fit within a regular frame height while looking "detached" from it.