Internals: Extracted some of the tab bar shrinking code into a ShrinkWidths() function so columns/table can use it.

imgui_internal.h

@@ -811,7 +811,7 @@ struct ImGuiNextItemData
 // Tabs
 //-----------------------------------------------------------------------------
 
-struct ImGuiTabBarSortItem
+struct ImGuiShrinkWidthItem
 {
     int             Index;
     float           Width;
@@ -976,7 +976,7 @@ struct ImGuiContext
     ImPool<ImGuiTabBar>             TabBars;
     ImGuiTabBar*                    CurrentTabBar;
     ImVector<ImGuiTabBarRef>        CurrentTabBarStack;
-    ImVector<ImGuiTabBarSortItem>   TabSortByWidthBuffer;
+    ImVector<ImGuiShrinkWidthItem>  ShrinkWidthBuffer;
 
     // Widget state
     ImVec2                  LastValidMousePos;
@@ -1495,6 +1495,7 @@ namespace ImGui
     IMGUI_API void          PopItemFlag();
     IMGUI_API bool          IsItemToggledSelection();                                           // was the last item selection toggled? (after Selectable(), TreeNode() etc. We only returns toggle _event_ in order to handle clipping correctly)
     IMGUI_API ImVec2        GetWorkRectMax();
+    IMGUI_API void          ShrinkWidths(ImGuiShrinkWidthItem* items, int count, float width_excess);
 
     // Logging/Capture
     IMGUI_API void          LogBegin(ImGuiLogType type, int auto_open_depth);   // -> BeginCapture() when we design v2 api, for now stay under the radar by using the old name.

imgui_widgets.cpp

@@ -1149,6 +1149,7 @@ void ImGui::Bullet()
 // - SeparatorEx() [Internal]
 // - Separator()
 // - SplitterBehavior() [Internal]
+// - ShrinkWidths() [Internal]
 //-------------------------------------------------------------------------
 
 void ImGui::Spacing()
@@ -1330,6 +1331,33 @@ bool ImGui::SplitterBehavior(const ImRect& bb, ImGuiID id, ImGuiAxis axis, float
     return held;
 }
 
+static int IMGUI_CDECL ShrinkWidthItemComparer(const void* lhs, const void* rhs)
+{
+    const ImGuiShrinkWidthItem* a = (const ImGuiShrinkWidthItem*)lhs;
+    const ImGuiShrinkWidthItem* b = (const ImGuiShrinkWidthItem*)rhs;
+    if (int d = (int)(b->Width - a->Width))
+        return d;
+    return (b->Index - a->Index);
+}
+
+// Shrink excess width from a set of item, by removing width from the larger items first.
+void ImGui::ShrinkWidths(ImGuiShrinkWidthItem* items, int count, float width_excess)
+{
+    if (count > 1)
+        ImQsort(items, (size_t)count, sizeof(ImGuiShrinkWidthItem), ShrinkWidthItemComparer);
+    int count_same_width = 1;
+    while (width_excess > 0.0f && count_same_width < count)
+    {
+        while (count_same_width < count && items[0].Width == items[count_same_width].Width)
+            count_same_width++;
+        float width_to_remove_per_item_max = (count_same_width < count) ? (items[0].Width - items[count_same_width].Width) : (items[0].Width - 1.0f);
+        float width_to_remove_per_item = ImMin(width_excess / count_same_width, width_to_remove_per_item_max);
+        for (int item_n = 0; item_n < count_same_width; item_n++)
+            items[item_n].Width -= width_to_remove_per_item;
+        width_excess -= width_to_remove_per_item * count_same_width;
+    }
+}
+
 //-------------------------------------------------------------------------
 // [SECTION] Widgets: ComboBox
 //-------------------------------------------------------------------------
@@ -6221,15 +6249,6 @@ static int IMGUI_CDECL TabItemComparerByVisibleOffset(const void* lhs, const voi
     return (int)(a->Offset - b->Offset);
 }
 
-static int IMGUI_CDECL TabBarSortItemComparer(const void* lhs, const void* rhs)
-{
-    const ImGuiTabBarSortItem* a = (const ImGuiTabBarSortItem*)lhs;
-    const ImGuiTabBarSortItem* b = (const ImGuiTabBarSortItem*)rhs;
-    if (int d = (int)(b->Width - a->Width))
-        return d;
-    return (b->Index - a->Index);
-}
-
 static ImGuiTabBar* GetTabBarFromTabBarRef(const ImGuiTabBarRef& ref)
 {
     ImGuiContext& g = *GImGui;
@@ -6403,10 +6422,8 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
         if (ImGuiTabItem* tab_to_select = TabBarTabListPopupButton(tab_bar)) // NB: Will alter BarRect.Max.x!
             scroll_track_selected_tab_id = tab_bar->SelectedTabId = tab_to_select->ID;
 
-    ImVector<ImGuiTabBarSortItem>& width_sort_buffer = g.TabSortByWidthBuffer;
-    width_sort_buffer.resize(tab_bar->Tabs.Size);
-
     // Compute ideal widths
+    g.ShrinkWidthBuffer.resize(tab_bar->Tabs.Size);
     float width_total_contents = 0.0f;
     ImGuiTabItem* most_recently_selected_tab = NULL;
     bool found_selected_tab_id = false;
@@ -6429,8 +6446,8 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
         width_total_contents += (tab_n > 0 ? g.Style.ItemInnerSpacing.x : 0.0f) + tab->WidthContents;
 
         // Store data so we can build an array sorted by width if we need to shrink tabs down
-        width_sort_buffer[tab_n].Index = tab_n;
+        g.ShrinkWidthBuffer[tab_n].Index = tab_n;
-        width_sort_buffer[tab_n].Width = tab->WidthContents;
+        g.ShrinkWidthBuffer[tab_n].Width = tab->WidthContents;
     }
 
     // Compute width
@@ -6439,21 +6456,9 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
     if (width_excess > 0.0f && (tab_bar->Flags & ImGuiTabBarFlags_FittingPolicyResizeDown))
     {
         // If we don't have enough room, resize down the largest tabs first
-        if (tab_bar->Tabs.Size > 1)
+        ShrinkWidths(g.ShrinkWidthBuffer.Data, g.ShrinkWidthBuffer.Size, width_excess);
-            ImQsort(width_sort_buffer.Data, (size_t)width_sort_buffer.Size, sizeof(ImGuiTabBarSortItem), TabBarSortItemComparer);
-        int tab_count_same_width = 1;
-        while (width_excess > 0.0f && tab_count_same_width < tab_bar->Tabs.Size)
-        {
-            while (tab_count_same_width < tab_bar->Tabs.Size && width_sort_buffer[0].Width == width_sort_buffer[tab_count_same_width].Width)
-                tab_count_same_width++;
-            float width_to_remove_per_tab_max = (tab_count_same_width < tab_bar->Tabs.Size) ? (width_sort_buffer[0].Width - width_sort_buffer[tab_count_same_width].Width) : (width_sort_buffer[0].Width - 1.0f);
-            float width_to_remove_per_tab = ImMin(width_excess / tab_count_same_width, width_to_remove_per_tab_max);
-            for (int tab_n = 0; tab_n < tab_count_same_width; tab_n++)
-                width_sort_buffer[tab_n].Width -= width_to_remove_per_tab;
-            width_excess -= width_to_remove_per_tab * tab_count_same_width;
-        }
         for (int tab_n = 0; tab_n < tab_bar->Tabs.Size; tab_n++)
-            tab_bar->Tabs[width_sort_buffer[tab_n].Index].Width = (float)(int)width_sort_buffer[tab_n].Width;
+            tab_bar->Tabs[g.ShrinkWidthBuffer[tab_n].Index].Width = (float)(int)g.ShrinkWidthBuffer[tab_n].Width;
     }
     else
     {