initialize Subroutine

   pure subroutine initialize(self, string, color_fg, color_bg, style)
   !< Initialize element.
   class(element_object), intent(inout)        :: self     !< element.
   class(*),              intent(in), optional :: string   !< Element string.
   character(len=*),      intent(in), optional :: color_fg !< Foreground color.
   character(len=*),      intent(in), optional :: color_bg !< Background color.
   character(len=*),      intent(in), optional :: style    !< Style.

   call self%destroy
   self%string = UCS4_''
   if (present(string)) then
      select type(string)
#if defined ASCII_SUPPORTED && defined ASCII_NEQ_DEFAULT
      type is(character(len=*, kind=ASCII))
         self%string = string
#endif
#ifdef UCS4_SUPPORTED
      type is(character(len=*, kind=UCS4))
         self%string = string
#endif
      type is(character(len=*))
         self%string = string
      endselect
   endif
   self%color_fg = '' ; if (present(color_fg)) self%color_fg = color_fg
   self%color_bg = '' ; if (present(color_bg)) self%color_bg = color_bg
   self%style = '' ; if (present(style)) self%style = style
   endsubroutine initialize