Tables: distinguishing per-column IsVisible from IsRequestOutput which is returned to user. Clarified clipping rules/requirements. Comments.

Author: ocornut

imgui.h

@@ -669,7 +669,7 @@ namespace ImGui
     //      TableNextColumn() will automatically wrap-around into the next row if needed.
     //    - IMPORTANT: Comparatively to the old Columns() API, we need to call TableNextColumn() for the first column!
     //    - Both TableSetColumnIndex() and TableNextColumn() return false when the column is not visible, so you can
-    //      skip submitting the contents of a cell BUT ONLY if you know the contents is not going to alter row height.
+    //      skip submitting the contents of a cell BUT ONLY if you know it is not going to contribute to row height.
     //      In many situations, you may skip submitting contents for every columns but one (e.g. the first one).
     //    - Summary of possible call flow:
     //      ----------------------------------------------------------------------------------------------------------
@@ -1055,7 +1055,7 @@ enum ImGuiTableFlags_
     ImGuiTableFlags_None                            = 0,
     ImGuiTableFlags_Resizable                       = 1 << 0,   // Allow resizing columns.
     ImGuiTableFlags_Reorderable                     = 1 << 1,   // Allow reordering columns in header row (need calling TableSetupColumn() + TableHeadersRow() to display headers)
-    ImGuiTableFlags_Hideable                        = 1 << 2,   // Allow hiding columns in context menu.
+    ImGuiTableFlags_Hideable                        = 1 << 2,   // Allow hiding/disabling columns in context menu.
     ImGuiTableFlags_Sortable                        = 1 << 3,   // Allow sorting on one column (sort_specs_count will always be == 1). Call TableGetSortSpecs() to obtain sort specs.
     ImGuiTableFlags_MultiSortable                   = 1 << 4,   // Allow sorting on multiple columns by holding Shift (sort_specs_count may be > 1). Call TableGetSortSpecs() to obtain sort specs.
     ImGuiTableFlags_NoSavedSettings                 = 1 << 5,   // Disable persisting columns order, width and sort settings in the .ini file.
@@ -1095,14 +1095,14 @@ enum ImGuiTableFlags_
 enum ImGuiTableColumnFlags_
 {
     ImGuiTableColumnFlags_None                      = 0,
-    ImGuiTableColumnFlags_DefaultHide               = 1 << 0,   // Default as a hidden column.
+    ImGuiTableColumnFlags_DefaultHide               = 1 << 0,   // Default as a hidden/disabled column.
     ImGuiTableColumnFlags_DefaultSort               = 1 << 1,   // Default as a sorting column.
     ImGuiTableColumnFlags_WidthStretch              = 1 << 2,   // Column will stretch. Preferable with horizontal scrolling disabled (default if table sizing policy is _ColumnsWidthStretch).
     ImGuiTableColumnFlags_WidthFixed                = 1 << 3,   // Column will not stretch. Preferable with horizontal scrolling enabled (default if table sizing policy is _ColumnsWidthFixed and table is resizable).
     ImGuiTableColumnFlags_WidthAutoResize           = 1 << 4,   // Column will not stretch and keep resizing based on submitted contents (default if table sizing policy is _ColumnsWidthFixed and table is not resizable).
     ImGuiTableColumnFlags_NoResize                  = 1 << 5,   // Disable manual resizing.
     ImGuiTableColumnFlags_NoReorder                 = 1 << 6,   // Disable manual reordering this column, this will also prevent other columns from crossing over this column.
-    ImGuiTableColumnFlags_NoHide                    = 1 << 7,   // Disable ability to hide this column.
+    ImGuiTableColumnFlags_NoHide                    = 1 << 7,   // Disable ability to hide/disable this column.
     ImGuiTableColumnFlags_NoClip                    = 1 << 8,   // Disable clipping for this column (all NoClip columns will render in a same draw command).
     ImGuiTableColumnFlags_NoSort                    = 1 << 9,   // Disable ability to sort on this field (even if ImGuiTableFlags_Sortable is set on the table).
     ImGuiTableColumnFlags_NoSortAscending           = 1 << 10,  // Disable ability to sort in the ascending direction.

imgui_demo.cpp

@@ -3518,9 +3518,7 @@ static void ShowDemoWindowTables()
                 ImGui::TableNextRow();
                 for (int column = 0; column < 3; column++)
                 {
-                    if (!ImGui::TableSetColumnIndex(column))
-                        continue;
-
+                    ImGui::TableSetColumnIndex(column);
                     char buf[32];
                     sprintf(buf, "Hello %d,%d", column, row);
                     if (contents_type == CT_Text)
@@ -3861,20 +3859,22 @@ static void ShowDemoWindowTables()
         {
             ImGui::TableSetupScrollFreeze(freeze_cols, freeze_rows);
             ImGui::TableSetupColumn("Line #", ImGuiTableColumnFlags_NoHide); // Make the first column not hideable to match our use of TableSetupScrollFreeze()
-            ImGui::TableSetupColumn("One", ImGuiTableColumnFlags_None);
-            ImGui::TableSetupColumn("Two", ImGuiTableColumnFlags_None);
-            ImGui::TableSetupColumn("Three", ImGuiTableColumnFlags_None);
-            ImGui::TableSetupColumn("Four", ImGuiTableColumnFlags_None);
-            ImGui::TableSetupColumn("Five", ImGuiTableColumnFlags_None);
-            ImGui::TableSetupColumn("Six", ImGuiTableColumnFlags_None);
+            ImGui::TableSetupColumn("One");
+            ImGui::TableSetupColumn("Two");
+            ImGui::TableSetupColumn("Three");
+            ImGui::TableSetupColumn("Four");
+            ImGui::TableSetupColumn("Five");
+            ImGui::TableSetupColumn("Six");
             ImGui::TableHeadersRow();
             for (int row = 0; row < 20; row++)
             {
                 ImGui::TableNextRow();
                 for (int column = 0; column < 7; column++)
                 {
-                    // Both TableNextColumn() and TableSetColumnIndex() return false when a column is not visible, which can be used for clipping.
-                    if (!ImGui::TableSetColumnIndex(column))
+                    // Both TableNextColumn() and TableSetColumnIndex() return false when a column is not visible.
+                    // Because here we know that A) all our columns are contributing the same to row height and B) column 0 is always visible,
+                    // we only always submit this one column.
+                    if (!ImGui::TableSetColumnIndex(column) && column > 0)
                         continue;
                     if (column == 0)
                         ImGui::Text("Line %d", row);
@@ -4809,8 +4809,8 @@ static void ShowDemoWindowTables()
                         }
                     }
 
-                    ImGui::TableNextColumn();
-                    ImGui::TextUnformatted(item->Name);
+                    if (ImGui::TableNextColumn())
+                        ImGui::TextUnformatted(item->Name);
 
                     // Here we demonstrate marking our data set as needing to be sorted again if we modified a quantity,
                     // and we are currently sorting on the column showing the Quantity.
@@ -4825,17 +4825,17 @@ static void ShowDemoWindowTables()
                         if (sorts_specs_using_quantity && ImGui::IsItemDeactivated()) { items_need_sort = true; }
                     }
 
-                    ImGui::TableNextColumn();
-                    ImGui::Text("%d", item->Quantity);
+                    if (ImGui::TableNextColumn())
+                        ImGui::Text("%d", item->Quantity);
 
                     ImGui::TableNextColumn();
                     if (show_wrapped_text)
                         ImGui::TextWrapped("Lorem ipsum dolor sit amet");
                     else
                         ImGui::Text("Lorem ipsum dolor sit amet");
 
-                    ImGui::TableNextColumn();
-                    ImGui::Text("1234");
+                    if (ImGui::TableNextColumn())
+                        ImGui::Text("1234");
 
                     ImGui::PopID();
                 }

imgui_internal.h

@@ -1932,7 +1932,9 @@ struct ImGuiTableColumn
     ImGuiTableDrawChannelIdx DrawChannelUnfrozen;
     bool                    IsEnabled;                      // Is the column not marked Hidden by the user? (even if off view, e.g. clipped by scrolling).
     bool                    IsEnabledNextFrame;
-    bool                    IsClipped;                      // Is not actually in view (e.g. not overlapping the host window clipping rectangle).
+    bool                    IsVisibleX;                     // Is actually in view (e.g. overlapping the host window clipping rectangle, not scrolled).
+    bool                    IsVisibleY;
+    bool                    IsRequestOutput;                // Return value for TableSetColumnIndex() / TableNextColumn(): whether we request user to output contents or not.
     bool                    IsSkipItems;                    // Do we want item submissions to this column to be completely ignored (no layout will happen).
     ImS8                    NavLayerCurrent;                // ImGuiNavLayer in 1 byte
     ImS8                    SortDirection;                  // ImGuiSortDirection_Ascending or ImGuiSortDirection_Descending
@@ -1971,8 +1973,9 @@ struct ImGuiTable
     ImSpan<ImGuiTableColumnIdx> DisplayOrderToIndex;        // Point within RawData[]. Store display order of columns (when not reordered, the values are 0...Count-1)
     ImSpan<ImGuiTableCellData>  RowCellData;                // Point within RawData[]. Store cells background requests for current row.
     ImU64                       EnabledMaskByDisplayOrder;  // Column DisplayOrder -> IsEnabled map
-    ImU64                       EnabledUnclippedMaskByIndex;// Enabled and not Clipped, aka "actually visible" "not hidden by some scrolling"
     ImU64                       EnabledMaskByIndex;         // Column Index -> IsEnabled map (== not hidden by user/api) in a format adequate for iterating column without touching cold data
+    ImU64                       VisibleMaskByIndex;         // Column Index -> IsVisibleX|IsVisibleY map (== not hidden by user/api && not hidden by scrolling/cliprect)
+    ImU64                       RequestOutputMaskByIndex;   // Column Index -> IsVisible || AutoFit (== expect user to submit items)
     ImGuiTableFlags             SettingsLoadedFlags;        // Which data were loaded from the .ini file (e.g. when order is not altered we won't save order)
     int                         SettingsOffset;             // Offset in g.SettingsTables
     int                         LastFrameActive;
@@ -2280,7 +2283,7 @@ namespace ImGui
     // Tables: Candidates for public api
     IMGUI_API void          TableOpenContextMenu(int column_n = -1);
     IMGUI_API void          TableSetColumnWidth(int column_n, float width);
-    IMGUI_API bool          TableGetColumnIsEnabled(int column_n = -1);  // Return false when column is disabled (hidden) by user (e.g. via context menu, or _DefaultHide flag)
+    IMGUI_API bool          TableGetColumnIsEnabled(int column_n = -1);  // Return false when column is disabled (hidden by user/api, e.g. via context menu, or _DefaultHide flag)
     IMGUI_API void          TableSetColumnIsEnabled(int column_n, bool enabled);
     IMGUI_API void          TableSetColumnSortDirection(int column_n, ImGuiSortDirection sort_direction, bool append_to_sort_specs);
     IMGUI_API float         TableGetHeaderRowHeight();