TabBar: Internals: added TabItemSpacing(). (#8349, #3291)

imgui_internal.h

@@ -2612,6 +2612,8 @@ enum ImGuiTabItemFlagsPrivate_
     ImGuiTabItemFlags_SectionMask_              = ImGuiTabItemFlags_Leading | ImGuiTabItemFlags_Trailing,
     ImGuiTabItemFlags_NoCloseButton             = 1 << 20,  // Track whether p_open was set or not (we'll need this info on the next frame to recompute ContentWidth during layout)
     ImGuiTabItemFlags_Button                    = 1 << 21,  // Used by TabItemButton, change the tab item behavior to mimic a button
+    ImGuiTabItemFlags_Invisible                 = 1 << 22,  // To reserve space e.g. with ImGuiTabItemFlags_Leading
+    //ImGuiTabItemFlags_Unsorted                = 1 << 23,  // [Docking] Trailing tabs with the _Unsorted flag will be sorted based on the DockOrder of their Window.
 };
 
 // Storage for one active tab item (sizeof() 40 bytes)
@@ -3378,6 +3380,7 @@ namespace ImGui
     IMGUI_API void          TabBarQueueReorderFromMousePos(ImGuiTabBar* tab_bar, 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 void          TabItemSpacing(const char* str_id, ImGuiTabItemFlags flags, float width);
     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_widgets.cpp

@@ -9925,7 +9925,7 @@ bool    ImGui::BeginTabItem(const char* label, bool* p_open, ImGuiTabItemFlags f
         IM_ASSERT_USER_ERROR(tab_bar, "Needs to be called between BeginTabBar() and EndTabBar()!");
         return false;
     }
-    IM_ASSERT(!(flags & ImGuiTabItemFlags_Button)); // BeginTabItem() Can't be used with button flags, use TabItemButton() instead!
+    IM_ASSERT((flags & ImGuiTabItemFlags_Button) == 0); // BeginTabItem() Can't be used with button flags, use TabItemButton() instead!
 
     bool ret = TabItemEx(tab_bar, label, p_open, flags, NULL);
     if (ret && !(flags & ImGuiTabItemFlags_NoPushId))
@@ -9971,6 +9971,23 @@ bool    ImGui::TabItemButton(const char* label, ImGuiTabItemFlags flags)
     return TabItemEx(tab_bar, label, NULL, flags | ImGuiTabItemFlags_Button | ImGuiTabItemFlags_NoReorder, NULL);
 }
 
+void    ImGui::TabItemSpacing(const char* str_id, ImGuiTabItemFlags flags, float width)
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
+    if (window->SkipItems)
+        return;
+
+    ImGuiTabBar* tab_bar = g.CurrentTabBar;
+    if (tab_bar == NULL)
+    {
+        IM_ASSERT_USER_ERROR(tab_bar != NULL, "Needs to be called between BeginTabBar() and EndTabBar()!");
+        return;
+    }
+    SetNextItemWidth(width);
+    TabItemEx(tab_bar, str_id, NULL, flags | ImGuiTabItemFlags_Button | ImGuiTabItemFlags_NoReorder | ImGuiTabItemFlags_Invisible, NULL);
+}
+
 bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open, ImGuiTabItemFlags flags, ImGuiWindow* docked_window)
 {
     // Layout whole tab bar if not already done
@@ -10116,8 +10133,11 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     ImGuiButtonFlags button_flags = ((is_tab_button ? ImGuiButtonFlags_PressedOnClickRelease : ImGuiButtonFlags_PressedOnClick) | ImGuiButtonFlags_AllowOverlap);
     if (g.DragDropActive)
         button_flags |= ImGuiButtonFlags_PressedOnDragDropHold;
-    bool hovered, held;
+    bool hovered, held, pressed;
-    bool pressed = ButtonBehavior(bb, id, &hovered, &held, button_flags);
+    if (flags & ImGuiTabItemFlags_Invisible)
+        hovered = held = pressed = false;
+    else
+        pressed = ButtonBehavior(bb, id, &hovered, &held, button_flags);
     if (pressed && !is_tab_button)
         TabBarQueueFocus(tab_bar, tab);
 
@@ -10149,6 +10169,9 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
 #endif
 
     // Render tab shape
+    const bool is_visible = (g.LastItemData.StatusFlags & ImGuiItemStatusFlags_Visible) && !(flags & ImGuiTabItemFlags_Invisible);
+    if (is_visible)
+    {
         ImDrawList* display_draw_list = window->DrawList;
         const ImU32 tab_col = GetColorU32((held || hovered) ? ImGuiCol_TabHovered : tab_contents_visible ? (tab_bar_focused ? ImGuiCol_TabSelected : ImGuiCol_TabDimmedSelected) : (tab_bar_focused ? ImGuiCol_Tab : ImGuiCol_TabDimmed));
         TabItemBackground(display_draw_list, bb, flags, tab_col);
@@ -10191,11 +10214,6 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
             TabBarCloseTab(tab_bar, tab);
         }
 
-    // Restore main window position so user can draw there
-    if (want_clip_rect)
-        PopClipRect();
-    window->DC.CursorPos = backup_main_cursor_pos;
-
         // Tooltip
         // (Won't work over the close button because ItemOverlap systems messes up with HoveredIdTimer-> seems ok)
         // (We test IsItemHovered() to discard e.g. when another item is active or drag and drop over the tab bar, which g.HoveredId ignores)
@@ -10204,6 +10222,12 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
         if (text_clipped && g.HoveredId == id && !held)
             if (!(tab_bar->Flags & ImGuiTabBarFlags_NoTooltip) && !(tab->Flags & ImGuiTabItemFlags_NoTooltip))
                 SetItemTooltip("%.*s", (int)(FindRenderedTextEnd(label) - label), label);
+    }
+
+    // Restore main window position so user can draw there
+    if (want_clip_rect)
+        PopClipRect();
+    window->DC.CursorPos = backup_main_cursor_pos;
 
     IM_ASSERT(!is_tab_button || !(tab_bar->SelectedTabId == tab->ID && is_tab_button)); // TabItemButton should not be selected
     if (is_tab_button)