Tables: Fixed incorrect auto-fit of parent windows when using non-resizable weighted columns. (#5276)

docs/CHANGELOG.txt

@@ -74,6 +74,7 @@ Other Changes:
   trickled with the new input queue (happened on some backends only). (#2467, #1336)
 - Tables: Fixed incorrect border height used for logic when resizing one of several synchronized
   instance of a same table ID, when instances have a different height. (#3955).
+- Tables: Fixed incorrect auto-fit of parent windows when using non-resizable weighted columns. (#5276)
 - Inputs: Fixed IsMouseClicked() repeat mode rate being half of keyboard repeat rate.
 - ColorEdit: Fixed text baseline alignment after a SameLine() after a ColorEdit() with visible label.
 - Menus: Adjusted BeginMenu() closing logic so hovering void or non-MenuItem() in parent window

imgui.h

@@ -65,7 +65,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.88 WIP"
-#define IMGUI_VERSION_NUM           18718
+#define IMGUI_VERSION_NUM           18719
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 

imgui_internal.h

@@ -2346,6 +2346,7 @@ struct IMGUI_API ImGuiTable
     float                       InnerWidth;                 // User value passed to BeginTable(), see comments at the top of BeginTable() for details.
     float                       ColumnsGivenWidth;          // Sum of current column width
     float                       ColumnsAutoFitWidth;        // Sum of ideal column width in order nothing to be clipped, used for auto-fitting and content width submission in outer window
+    float                       ColumnsStretchSumWeights;   // Sum of weight of all enabled stretching columns
     float                       ResizedColumnNextWidth;
     float                       ResizeLockMinContentsX2;    // Lock minimum contents width while resizing down in order to not create feedback loops. But we allow growing the table.
     float                       RefScale;                   // Reference scale to be able to rescale columns on font/dpi changes.

imgui_tables.cpp

@@ -888,6 +888,7 @@ void ImGui::TableUpdateLayout(ImGuiTable* table)
         sum_width_requests += table->CellPaddingX * 2.0f;
     }
     table->ColumnsEnabledFixedCount = (ImGuiTableColumnIdx)count_fixed;
+    table->ColumnsStretchSumWeights = stretch_sum_weights;
 
     // [Part 4] Apply final widths based on requested widths
     const ImRect work_rect = table->WorkRect;
@@ -1284,17 +1285,23 @@ void    ImGui::EndTable()
     splitter->Merge(inner_window->DrawList);
 
     // Update ColumnsAutoFitWidth to get us ahead for host using our size to auto-resize without waiting for next BeginTable()
-    const float width_spacings = (table->OuterPaddingX * 2.0f) + (table->CellSpacingX1 + table->CellSpacingX2) * (table->ColumnsEnabledCount - 1);
+    float auto_fit_width_for_fixed = 0.0f;
-    table->ColumnsAutoFitWidth = width_spacings + (table->CellPaddingX * 2.0f) * table->ColumnsEnabledCount;
+    float auto_fit_width_for_stretched = 0.0f;
+    float auto_fit_width_for_stretched_min = 0.0f;
     for (int column_n = 0; column_n < table->ColumnsCount; column_n++)
         if (table->EnabledMaskByIndex & ((ImU64)1 << column_n))
         {
             ImGuiTableColumn* column = &table->Columns[column_n];
-            if ((column->Flags & ImGuiTableColumnFlags_WidthFixed) && !(column->Flags & ImGuiTableColumnFlags_NoResize))
+            float column_width_request = ((column->Flags & ImGuiTableColumnFlags_WidthFixed) && !(column->Flags & ImGuiTableColumnFlags_NoResize)) ? column->WidthRequest : TableGetColumnWidthAuto(table, column);
-                table->ColumnsAutoFitWidth += column->WidthRequest;
+            if (column->Flags & ImGuiTableColumnFlags_WidthFixed)
+                auto_fit_width_for_fixed += column_width_request;
             else
-                table->ColumnsAutoFitWidth += TableGetColumnWidthAuto(table, column);
+                auto_fit_width_for_stretched += column_width_request;
+            if ((column->Flags & ImGuiTableColumnFlags_WidthStretch) && (column->Flags & ImGuiTableColumnFlags_NoResize) != 0)
+                auto_fit_width_for_stretched_min = ImMax(auto_fit_width_for_stretched_min, column_width_request / (column->StretchWeight / table->ColumnsStretchSumWeights));
         }
+    const float width_spacings = (table->OuterPaddingX * 2.0f) + (table->CellSpacingX1 + table->CellSpacingX2) * (table->ColumnsEnabledCount - 1);
+    table->ColumnsAutoFitWidth = width_spacings + (table->CellPaddingX * 2.0f) * table->ColumnsEnabledCount + auto_fit_width_for_fixed + ImMax(auto_fit_width_for_stretched, auto_fit_width_for_stretched_min);
 
     // Update scroll
     if ((table->Flags & ImGuiTableFlags_ScrollX) == 0 && inner_window != outer_window)