         paths.push(new fabric.Line coords, @constant.path_style)
     paths
 
+  focus: (layer,pos)->
+    @div.scrollTo {
+      left : -200 + @constant.padding_left + pos * @constant.outer_width
+      top  : -200 + @constant.padding_top  + layer * @constant.outer_height
+    }
+
   destroy: (sha1)->
     # TODO remove sha1's related fabric objects
 

    setTimeout( @draw.bind(@,sha1,layer,pos),0 )

  # TODO
  # focus: (sha1)->
  # ref_on_commit: (ref)
  # ref_on_ref:    (ref1, ref2)
  add_commit: (commit)->

      @canvas_inc_height()
      scroll = true
    if scroll
      @focus( layer, pos )
    group = new fabric.Group([], group_pos)

  draw_commit: (sha1)->
