Also cache row_ref

The `row_ref` method is called once for each column in a row and once at the
row level.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/axlsx/workbook/worksheet/row.rb b/lib/axlsx/workbook/worksheet/row.rb
index 16116835..dc0320b7 100644
--- a/lib/axlsx/workbook/worksheet/row.rb
+++ b/lib/axlsx/workbook/worksheet/row.rb
@@ -89,7 +89,7 @@ module Axlsx
     # @param [String] str The string this rows xml will be appended to.
     # @return [String]
     def to_xml_string(r_index, str = +'')
-      serialized_tag('row', str, :r => r_index + 1) do
+      serialized_tag('row', str, :r => Axlsx.row_ref(r_index)) do
         each_with_index { |cell, c_index| cell.to_xml_string(r_index, c_index, str) }
       end
     end