🔧 [Text] Improve alg for horiz lines at column labels

Author: ronisbr

src/backends/text/display.jl

@@ -358,8 +358,11 @@ function _text__print_column_label_horizontal_line(
             # We must compute if the cell at the top or at the bottom from the current
             # horizontal line is merged. Notice that if we are at the top of the table, the
             # effect is equal to have a merged cell above it.
-            tcm = _is_column_label_cell_merged(table_data, row_number,     j + 1) || top
-            bcm = _is_column_label_cell_merged(table_data, row_number + 1, j + 1)
+            top_j₀,    top_j₁    = _column_label_limits(table_data, row_number,     j + 1)
+            bottom_j₀, bottom_j₁ = _column_label_limits(table_data, row_number + 1, j + 1)
+
+            tcm = (top_j₀    != top_j₁)    && (j + 1 != top_j₀   ) || top
+            bcm = (bottom_j₀ != bottom_j₁) && (j + 1 != bottom_j₀)
 
             if tf.suppress_vertical_lines_at_column_labels
                 bcm = tcm = true

src/printing_state/information.jl

@@ -75,21 +75,11 @@ end
 """
     _is_column_label_cell_merged(table_data::TableData, i::Int, j::Int) -> Bool
 
-Return whether the cell at `(i, j)` is a merged column label cell. Notice that this function
-returns `true` only if `(i, j)` is in the middle of the merged cell. If the merged cell
-starts at `(i, j)`, this function returns `false`.
+Return whether the cell at `(i, j)` is a merged column label cell.
 """
 function _is_column_label_cell_merged(table_data::TableData, i::Int, j::Int)
-    isnothing(table_data.merge_column_label_cells) && return false
-
-    # Check if this cell must be merged or if is is part of a merged cell.
-    for mc in table_data.merge_column_label_cells
-        if mc.i == i && (mc.j < j <= mc.j + mc.column_span - 1)
-            return true
-        end
-    end
-
-    return false
+    j₀, j₁ = _column_label_limits(table_data, i, j)
+    return j₀ != j₁
 end
 
 """