1 files changed, 10 insertions, 0 deletions
diff --git a/ext/tk/lib/tkextlib/iwidgets/canvasprintbox.rb b/ext/tk/lib/tkextlib/iwidgets/canvasprintbox.rb
index 1e2a476591..fa5e90ad05 100644
--- a/ext/tk/lib/tkextlib/iwidgets/canvasprintbox.rb
+++ b/ext/tk/lib/tkextlib/iwidgets/canvasprintbox.rb
@@ -18,6 +18,16 @@ class Tk::Iwidgets::Canvasprintbox
   WidgetClassName = 'Canvasprintbox'.freeze
   WidgetClassNames[WidgetClassName] = self
 
+  def __strval_optkeys
+    super() << 'filename'
+  end
+  private :__strval_optkeys
+
+  def __boolval_optkeys
+    super() << 'stretch'
+  end
+  private :__boolval_optkeys
+
   def get_output
     tk_call(@path, 'getoutput')
   end