file-menu:print-callback in frame:editor-mixin

This method is called when the print menu-item of the file-menu menu is selected.

• (send a-frame:editor-mixin file-menu:print-callback item evt) -> void
     item : (instance (derived-from menu-item%))
     evt : (instance control-event%)

  Calls the print method of editor<%> with the default arguments, except that the output-mode argument is the result of calling preferences:get with 'framework:print-output-mode.