Tables: comments. (#7937)

imgui.h

@@ -1948,7 +1948,7 @@ enum ImGuiTableColumnFlags_
     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.
     ImGuiTableColumnFlags_NoSortDescending      = 1 << 11,  // Disable ability to sort in the descending direction.
-    ImGuiTableColumnFlags_NoHeaderLabel         = 1 << 12,  // TableHeadersRow() will not submit horizontal label for this column. Convenient for some small columns. Name will still appear in context menu or in angled headers.
+    ImGuiTableColumnFlags_NoHeaderLabel         = 1 << 12,  // TableHeadersRow() will submit an empty label for this column. Convenient for some small columns. Name will still appear in context menu or in angled headers. You may append into this cell by calling TableSetColumnIndex() right after the TableHeadersRow() call.
     ImGuiTableColumnFlags_NoHeaderWidth         = 1 << 13,  // Disable header text width contribution to automatic column width.
     ImGuiTableColumnFlags_PreferSortAscending   = 1 << 14,  // Make the initial sort direction Ascending when first sorting on this column (default).
     ImGuiTableColumnFlags_PreferSortDescending  = 1 << 15,  // Make the initial sort direction Descending when first sorting on this column.

imgui_demo.cpp

@@ -6403,7 +6403,11 @@ static void ShowDemoWindowTables()
             // FIXME: It would be nice to actually demonstrate full-featured selection using those checkbox.
             static bool column_selected[3] = {};
 
-            // Instead of calling TableHeadersRow() we'll submit custom headers ourselves
+            // Instead of calling TableHeadersRow() we'll submit custom headers ourselves.
+            // (A different approach is also possible:
+            //    - Specify ImGuiTableColumnFlags_NoHeaderLabel in some TableSetupColumn() call.
+            //    - Call TableHeadersRow() normally. This will submit TableHeader() with no name.
+            //    - Then call TableSetColumnIndex() to position yourself in the column and submit your stuff e.g. Checkbox().)
             ImGui::TableNextRow(ImGuiTableRowFlags_Headers);
             for (int column = 0; column < COLUMNS_COUNT; column++)
             {
@@ -6418,6 +6422,7 @@ static void ShowDemoWindowTables()
                 ImGui::PopID();
             }
 
+            // Submit table contents
             for (int row = 0; row < 5; row++)
             {
                 ImGui::TableNextRow();

imgui_tables.cpp

@@ -3018,7 +3018,8 @@ float ImGui::TableGetHeaderAngledMaxLabelWidth()
 // The intent is that advanced users willing to create customized headers would not need to use this helper
 // and can create their own! For example: TableHeader() may be preceded by Checkbox() or other custom widgets.
 // See 'Demo->Tables->Custom headers' for a demonstration of implementing a custom version of this.
-// This code is constructed to not make much use of internal functions, as it is intended to be a template to copy.
+// This code is intentionally written to not make much use of internal functions, to give you better direction
+// if you need to write your own.
 // FIXME-TABLE: TableOpenContextMenu() and TableGetHeaderRowHeight() are not public.
 void ImGui::TableHeadersRow()
 {
@@ -3026,7 +3027,8 @@ void ImGui::TableHeadersRow()
     ImGuiTable* table = g.CurrentTable;
     IM_ASSERT(table != NULL && "Need to call TableHeadersRow() after BeginTable()!");
 
-    // Layout if not already done (this is automatically done by TableNextRow, we do it here solely to facilitate stepping in debugger as it is frequent to step in TableUpdateLayout)
+    // Call layout if not already done. This is automatically done by TableNextRow: we do it here _only_ to make
+    // it easier to debug-step in TableUpdateLayout(). Your own version of this function doesn't need this.
     if (!table->IsLayoutLocked)
         TableUpdateLayout(table);
 
@@ -3043,8 +3045,7 @@ void ImGui::TableHeadersRow()
         if (!TableSetColumnIndex(column_n))
             continue;
 
-        // Push an id to allow unnamed labels (generally accidental, but let's behave nicely with them)
+        // Push an id to allow empty/unnamed headers. This is also idiomatic as it ensure there is a consistent ID path to access columns (for e.g. automation)
-        // In your own code you may omit the PushID/PopID all-together, provided you know they won't collide.
         const char* name = (TableGetColumnFlags(column_n) & ImGuiTableColumnFlags_NoHeaderLabel) ? "" : TableGetColumnName(column_n);
         PushID(column_n);
         TableHeader(name);