digraph UML {
  rankdir  = BT
     
  fontname = "Courier New"
  fontsize = 10
     
  node [ fontname = "Courier New", fontsize = 10, shape = "record" ];
  edge [ fontname = "Courier New", fontsize = 10 ];
   
   input_method_t -> edit_t [arrowhead=none]

   subgraph cluster_1 {
    input_method_t -> input_engine_t [constraint=false arrowhead=vee style=dashed]
   }
   
   input_method_default_t -> input_method_t [arrowhead=empty style=dashed]
   input_method_sdl_t -> input_method_t [arrowhead=empty style=dashed]
   input_method_null_t -> input_method_t [arrowhead=empty style=dashed]
   
   input_engine_pinyin_t -> input_engine_t[arrowhead=empty style=dashed]
   input_engine_null_t -> input_engine_t[arrowhead=empty style=dashed]
   
   keyboard_t ->input_method_default_t [arrowhead=none]
}