Tables: Added ImGuiTableFlags_NoHostExtendX (#3605) marked as WIP, will probably rename.

Moved some code from BeginTable() to TableUpdateLayout() to late latch some of the required data.

imgui.h

@@ -1075,20 +1075,21 @@ enum ImGuiTableFlags_
     ImGuiTableFlags_ColumnsWidthFixed               = 1 << 14,  // Default if ScrollX is on. Columns will default to use _WidthFixed or _WidthAutoResize policy (if Resizable is off). Read description above for more details.
     ImGuiTableFlags_SameWidths                      = 1 << 15,  // Make all columns the same widths which is useful with Fixed columns policy (but granted by default with Stretch policy + no resize). Implicitly enable ImGuiTableFlags_NoKeepColumnsVisible and disable ImGuiTableFlags_Resizable.
     ImGuiTableFlags_NoHeadersWidth                  = 1 << 16,  // Disable headers' contribution to automatic width calculation.
-    ImGuiTableFlags_NoHostExtendY                   = 1 << 17,  // Disable extending past the limit set by outer_size.y, only meaningful when neither of ScrollX|ScrollY are set (data below the limit will be clipped and not visible)
-    ImGuiTableFlags_NoKeepColumnsVisible            = 1 << 18,  // Disable keeping column always minimally visible when ScrollX is off and table gets too small.
-    ImGuiTableFlags_PreciseWidths                   = 1 << 19,  // Disable distributing remainder width to stretched columns (width allocation on a 100-wide table with 3 columns: Without this flag: 33,33,34. With this flag: 33,33,33). With larger number of columns, resizing will appear to be less smooth.
-    ImGuiTableFlags_NoClip                          = 1 << 20,  // Disable clipping rectangle for every individual columns (reduce draw command count, items will be able to overflow into other columns). Generally incompatible with TableSetupScrollFreeze().
+    ImGuiTableFlags_NoHostExtendX                   = 1 << 17,  // Disable extending table past the limit required by the right-most columns. Only meaningful with Fixed columns and when neither ScrollX nor ScrollY are set.
+    ImGuiTableFlags_NoHostExtendY                   = 1 << 18,  // Disable extending table past the limit set by outer_size.y. Only meaningful when neither ScrollX nor ScrollY are set (data below the limit will be clipped and not visible)
+    ImGuiTableFlags_NoKeepColumnsVisible            = 1 << 19,  // Disable keeping column always minimally visible when ScrollX is off and table gets too small.
+    ImGuiTableFlags_PreciseWidths                   = 1 << 20,  // Disable distributing remainder width to stretched columns (width allocation on a 100-wide table with 3 columns: Without this flag: 33,33,34. With this flag: 33,33,33). With larger number of columns, resizing will appear to be less smooth.
+    ImGuiTableFlags_NoClip                          = 1 << 21,  // Disable clipping rectangle for every individual columns (reduce draw command count, items will be able to overflow into other columns). Generally incompatible with TableSetupScrollFreeze().
     // Padding
-    ImGuiTableFlags_PadOuterX                       = 1 << 21,  // Default if BordersOuterV is on. Enable outer-most padding.
-    ImGuiTableFlags_NoPadOuterX                     = 1 << 22,  // Default if BordersOuterV is off. Disable outer-most padding.
-    ImGuiTableFlags_NoPadInnerX                     = 1 << 23,  // Disable inner padding between columns (double inner padding if BordersOuterV is on, single inner padding if BordersOuterV is off).
+    ImGuiTableFlags_PadOuterX                       = 1 << 22,  // Default if BordersOuterV is on. Enable outer-most padding.
+    ImGuiTableFlags_NoPadOuterX                     = 1 << 23,  // Default if BordersOuterV is off. Disable outer-most padding.
+    ImGuiTableFlags_NoPadInnerX                     = 1 << 24,  // Disable inner padding between columns (double inner padding if BordersOuterV is on, single inner padding if BordersOuterV is off).
     // Scrolling
-    ImGuiTableFlags_ScrollX                         = 1 << 24,  // Enable horizontal scrolling. Require 'outer_size' parameter of BeginTable() to specify the container size. Changes default sizing policy. Because this create a child window, ScrollY is currently generally recommended when using ScrollX.
-    ImGuiTableFlags_ScrollY                         = 1 << 25,  // Enable vertical scrolling. Require 'outer_size' parameter of BeginTable() to specify the container size.
+    ImGuiTableFlags_ScrollX                         = 1 << 25,  // Enable horizontal scrolling. Require 'outer_size' parameter of BeginTable() to specify the container size. Changes default sizing policy. Because this create a child window, ScrollY is currently generally recommended when using ScrollX.
+    ImGuiTableFlags_ScrollY                         = 1 << 26,  // Enable vertical scrolling. Require 'outer_size' parameter of BeginTable() to specify the container size.
     // Sorting
-    ImGuiTableFlags_SortMulti                       = 1 << 26,  // Hold shift when clicking headers to sort on multiple column. TableGetSortSpecs() may return specs where (SpecsCount > 1).
-    ImGuiTableFlags_SortTristate                    = 1 << 27   // Allow no sorting, disable default sorting. TableGetSortSpecs() may return specs where (SpecsCount == 0).
+    ImGuiTableFlags_SortMulti                       = 1 << 27,  // Hold shift when clicking headers to sort on multiple column. TableGetSortSpecs() may return specs where (SpecsCount > 1).
+    ImGuiTableFlags_SortTristate                    = 1 << 28   // Allow no sorting, disable default sorting. TableGetSortSpecs() may return specs where (SpecsCount == 0).
 };
 
 // Flags for ImGui::TableSetupColumn()

imgui_demo.cpp

@@ -4221,6 +4221,7 @@ static void ShowDemoWindowTables()
         ImGui::SetNextItemOpen(open_action != 0);
     if (ImGui::TreeNode("Outer size"))
     {
+        ImGui::Text("Using manual/explicit size:");
         if (ImGui::BeginTable("##table1", 3, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg, ImVec2(TEXT_BASE_WIDTH * 30, 0.0f)))
         {
             for (int row = 0; row < 5; row++)
@@ -4248,6 +4249,30 @@ static void ShowDemoWindowTables()
             }
             ImGui::EndTable();
         }
+        ImGui::Spacing();
+
+        // Showcasing use of ImGuiTableFlags_NoHostExtendX and ImGuiTableFlags_NoHostExtendY
+        // FIXME-TABLE: WIP API: Don't use yet, will probably rework/rename those flags.
+        ImGui::Text("Using NoHostExtend flags:");
+        static ImGuiTableFlags flags = ImGuiTableFlags_Borders | ImGuiTableFlags_Resizable | ImGuiTableFlags_ContextMenuInBody | ImGuiTableFlags_RowBg | ImGuiTableFlags_NoHostExtendX | ImGuiTableFlags_ColumnsWidthFixed;
+        ImGui::CheckboxFlags("ImGuiTableFlags_NoHostExtendX", &flags, ImGuiTableFlags_NoHostExtendX);
+        ImGui::CheckboxFlags("ImGuiTableFlags_NoHostExtendY", &flags, ImGuiTableFlags_NoHostExtendY);
+        if (ImGui::BeginTable("##table3", 3, flags, ImVec2(0.0f, TEXT_BASE_HEIGHT * 5.5f)))
+        {
+            for (int row = 0; row < 10; row++)
+            {
+                ImGui::TableNextRow();
+                for (int column = 0; column < 3; column++)
+                {
+                    ImGui::TableNextColumn();
+                    ImGui::Text("Cell %d,%d", column, row);
+                }
+            }
+            ImGui::EndTable();
+        }
+        ImGui::SameLine();
+        ImGui::Text("Hello!");
+
         ImGui::TreePop();
     }
 
@@ -4715,6 +4740,7 @@ static void ShowDemoWindowTables()
                     flags &= ~ImGuiTableFlags_ColumnsWidthStretch; // Can't specify both sizing polices so we clear the other
                 ImGui::SameLine(); HelpMarker("[Default if ScrollX is on]\nEnlarge as needed: enable scrollbar if ScrollX is enabled, otherwise extend parent window's contents rectangle. Only Fixed columns allowed. Stretched columns will calculate their width assuming no scrolling.");
                 ImGui::CheckboxFlags("ImGuiTableFlags_NoHeadersWidth", &flags, ImGuiTableFlags_NoHeadersWidth);
+                ImGui::CheckboxFlags("ImGuiTableFlags_NoHostExtendX", &flags, ImGuiTableFlags_NoHostExtendX);
                 ImGui::CheckboxFlags("ImGuiTableFlags_NoHostExtendY", &flags, ImGuiTableFlags_NoHostExtendY);
                 ImGui::CheckboxFlags("ImGuiTableFlags_NoKeepColumnsVisible", &flags, ImGuiTableFlags_NoKeepColumnsVisible);
                 ImGui::SameLine(); HelpMarker("Only available if ScrollX is disabled.");

imgui_internal.h

@@ -2072,6 +2072,7 @@ struct ImGuiTable
     bool                        IsResetAllRequest;
     bool                        IsResetDisplayOrderRequest;
     bool                        IsUnfrozen;                 // Set when we got past the frozen row.
+    bool                        IsOuterRectFitX;            // Set when outer_size value passed to BeginTable() is (>= -1.0f && <= 0.0f)
     bool                        MemoryCompacted;
     bool                        HostSkipItems;              // Backup of InnerWindow->SkipItem at the end of BeginTable(), because we will overwrite InnerWindow->SkipItem on a per-column basis
 

imgui_tables.cpp

@@ -38,7 +38,7 @@ Index of this file:
 // - TableSetupColumn()                         user submit columns details (optional)
 // - TableSetupScrollFreeze()                   user submit scroll freeze information (optional)
 //-----------------------------------------------------------------------------
-// - TableUpdateLayout() [Internal]             setup everything, lock all widths, columns positions, clipping rectangles. Automatically called by the FIRST call to TableNextRow() or TableHeadersRow().
+// - TableUpdateLayout() [Internal]             followup to BeginTable(): setup everything: widths, columns positions, clipping rectangles. Automatically called by the FIRST call to TableNextRow() or TableHeadersRow().
 //    | TableSetupDrawChannels()                - setup ImDrawList channels
 //    | TableUpdateBorders()                    - detect hovering columns for resize, ahead of contents submission
 //    | TableDrawContextMenu()                  - draw right-click context menu
@@ -280,6 +280,7 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     table->InnerWidth = inner_width;
     table->OuterRect = outer_rect;
     table->WorkRect = outer_rect;
+    table->IsOuterRectFitX = (outer_size.x >= -1.0f && outer_size.x <= 0.0f); // Bit ambiguous
 
     // When not using a child window, WorkRect.Max will grow as we append contents.
     if (use_child_window)
@@ -325,7 +326,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     table->HostBackupCursorMaxPos = inner_window->DC.CursorMaxPos;
     table->HostBackupItemWidth = outer_window->DC.ItemWidth;
     table->HostBackupItemWidthStackSize = outer_window->DC.ItemWidthStack.Size;
-    inner_window->ParentWorkRect = table->WorkRect;
     inner_window->DC.PrevLineSize = inner_window->DC.CurrLineSize = ImVec2(0.0f, 0.0f);
 
     // Padding and Spacing
@@ -356,13 +356,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     table->InnerClipRect.ClipWithFull(table->HostClipRect);
     table->InnerClipRect.Max.y = (flags & ImGuiTableFlags_NoHostExtendY) ? ImMin(table->InnerClipRect.Max.y, inner_window->WorkRect.Max.y) : inner_window->ClipRect.Max.y;
 
-    // Initial draw cmd starts with a BgClipRect that matches the one of its host, to facilitate merge draw commands by default.
-    // This is because all our cell highlight are manually clipped with BgClipRect
-    // Larger at first, if/after unfreezing will become same as tight
-    table->BgClipRect = table->InnerClipRect;
-    table->BgClipRectForDrawCmd = table->HostClipRect;
-    IM_ASSERT(table->BgClipRect.Min.y <= table->BgClipRect.Max.y);
-
     table->RowPosY1 = table->RowPosY2 = table->WorkRect.Min.y; // This is needed somehow
     table->RowTextBaseline = 0.0f; // This will be cleared again by TableBeginRow()
     table->FreezeRowsRequest = table->FreezeRowsCount = 0; // This will be setup by TableSetupScrollFreeze(), if any
@@ -373,8 +366,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     // Using opaque colors facilitate overlapping elements of the grid
     table->BorderColorStrong = GetColorU32(ImGuiCol_TableBorderStrong);
     table->BorderColorLight = GetColorU32(ImGuiCol_TableBorderLight);
-    table->BorderX1 = table->InnerClipRect.Min.x;// +((table->Flags & ImGuiTableFlags_BordersOuter) ? 0.0f : -1.0f);
-    table->BorderX2 = table->InnerClipRect.Max.x;// +((table->Flags & ImGuiTableFlags_BordersOuter) ? 0.0f : +1.0f);
 
     // Make table current
     const int table_idx = g.Tables.GetIndex(table);
@@ -1001,26 +992,39 @@ void ImGui::TableUpdateLayout(ImGuiTable* table)
     // [Part 8] Detect/store when we are hovering the unused space after the right-most column (so e.g. context menus can react on it)
     // Clear Resizable flag if none of our column are actually resizable (either via an explicit _NoResize flag, either
     // because of using _WidthAutoResize/_WidthStretch). This will hide the resizing option from the context menu.
+    const float unused_x1 = ImMax(table->WorkRect.Min.x, table->Columns[table->RightMostEnabledColumn].ClipRect.Max.x);
     if (is_hovering_table && table->HoveredColumnBody == -1)
     {
-        float unused_x1 = ImMax(table->WorkRect.Min.x, table->Columns[table->RightMostEnabledColumn].ClipRect.Max.x);
         if (g.IO.MousePos.x >= unused_x1)
             table->HoveredColumnBody = (ImGuiTableColumnIdx)table->ColumnsCount;
     }
     if (count_resizable == 0 && (table->Flags & ImGuiTableFlags_Resizable))
         table->Flags &= ~ImGuiTableFlags_Resizable;
 
-    // [Part 9] Allocate draw channels
+    // [Part 9] Lock actual OuterRect/WorkRect right-most position.
+    // This is done late to handle the case of fixed-columns tables not claiming more widths that they need.
+    // Because of this we are careful with uses of WorkRect and InnerClipRect before this point.
+    if ((table->Flags & ImGuiTableFlags_NoHostExtendX) && table->InnerWindow == table->OuterWindow && table->RightMostStretchedColumn == -1)
+    {
+        table->OuterRect.Max.x = table->WorkRect.Max.x = unused_x1;
+        table->InnerClipRect.Max.x = ImMin(table->InnerClipRect.Max.x, unused_x1);
+        table->IsOuterRectFitX = false;
+    }
+    table->InnerWindow->ParentWorkRect = table->WorkRect;
+    table->BorderX1 = table->InnerClipRect.Min.x;// +((table->Flags & ImGuiTableFlags_BordersOuter) ? 0.0f : -1.0f);
+    table->BorderX2 = table->InnerClipRect.Max.x;// +((table->Flags & ImGuiTableFlags_BordersOuter) ? 0.0f : +1.0f);
+
+    // [Part 10] Allocate draw channels and setup background cliprect
     TableSetupDrawChannels(table);
 
-    // [Part 10] Hit testing on borders
+    // [Part 11] Hit testing on borders
     if (table->Flags & ImGuiTableFlags_Resizable)
         TableUpdateBorders(table);
     table->LastFirstRowHeight = 0.0f;
     table->IsLayoutLocked = true;
     table->IsUsingHeaders = false;
 
-    // [Part 11] Context menu
+    // [Part 12] Context menu
     if (table->IsContextPopupOpen && table->InstanceCurrent == table->InstanceInteracted)
     {
         const ImGuiID context_menu_id = ImHashStr("##ContextMenu", 0, table->ID);
@@ -1227,14 +1231,14 @@ void    ImGui::EndTable()
     outer_window->DC.ItemWidth = table->HostBackupItemWidth;
     outer_window->DC.ItemWidthStack.Size = table->HostBackupItemWidthStackSize;
     outer_window->DC.ColumnsOffset = table->HostBackupColumnsOffset;
+    const float outer_width = table->IsOuterRectFitX ? table->ColumnsAutoFitWidth : table->WorkRect.GetWidth();
     if (inner_window != outer_window)
     {
         EndChild();
     }
     else
     {
-        ImVec2 item_size = table->OuterRect.GetSize();
-        item_size.x = table->ColumnsTotalWidth;
+        ImVec2 item_size(outer_width, table->OuterRect.GetHeight());
         ItemSize(item_size);
     }
 
@@ -1247,7 +1251,8 @@ void    ImGui::EndTable()
     }
     else
     {
-        outer_window->DC.CursorMaxPos.x = ImMax(backup_outer_max_pos_x, table->WorkRect.Min.x + table->ColumnsAutoFitWidth); // For auto-fit
+        outer_window->DC.CursorMaxPos.x = ImMax(backup_outer_max_pos_x, table->WorkRect.Min.x + outer_width); // For auto-fit
+        outer_window->DC.CursorPosPrevLine.x = table->WorkRect.Max.x; // For consistent reaction to SameLine() // FIXME: Should be a feature of layout/ItemAdd
     }
 
     // Save settings
@@ -2068,6 +2073,13 @@ void ImGui::TableSetupDrawChannels(ImGuiTable* table)
         }
         column->DrawChannelCurrent = column->DrawChannelFrozen;
     }
+
+    // Initial draw cmd starts with a BgClipRect that matches the one of its host, to facilitate merge draw commands by default.
+    // All our cell highlight are manually clipped with BgClipRect. When unfreezing it will be made smaller to fit scrolling rect.
+    // (This technically isn't part of setting up draw channels, but is reasonably related to be done here)
+    table->BgClipRect = table->InnerClipRect;
+    table->BgClipRectForDrawCmd = table->HostClipRect;
+    IM_ASSERT(table->BgClipRect.Min.y <= table->BgClipRect.Max.y);
 }
 
 // This function reorder draw channels based on matching clip rectangle, to facilitate merging them. Called by EndTable().