mapnik/docs/textrendering.gv

/* process with: dot textrendering.gv -Tsvg > textrendering.svg */
digraph textrendering {
  /* Classes without important virtual members: Round
     Classes with    important virtual members: Rect
     Pointers [style=dashed] */

  Renderer [color=red]
  rankdir="TD";
  text_placements[shape=box]
  text_placement_info[shape=box]
  node_ -> text_processor [label="tree_", style=dashed]
  TextSymbolizer -> text_placements [label="placement_options_", style=dashed]
  text_placements -> text_symbolizer_properties [label="properties"]
  text_placements -> text_placement_info [label="get_placement_info()", style=dashed]
  text_placement_info -> text_symbolizer_properties [label="properties"]
  text_placement_info -> text_path [label="placements", style=dashed]
  text_placement_info -> text_placement_info [label="next()"]
  text_symbolizer_properties -> text_processor [label="processor"]
  text_processor ->  processed_text [label="process()", style=dashed]
  processed_text -> string_info [label="get_string_info()", style=dashed]
  text_path -> Renderer [color=red, label="used by"]
  processed_text -> Renderer [color=red, label="owned by"]
  Renderer -> text_symbolizer_helper [color=red, label="creates"]
  text_symbolizer_helper -> placement_finder [color=red, label="creates"]
  placement_finder -> text_path [color=red, label="creates"]
  string_info -> placement_finder [color=red, label="used by"]
  text_processor -> Renderer [color=red, label="called by"]
  text_placement_info -> Renderer [color=red, label="used by"]
  
  
  node_[label="node"]
  node_ -> text_node [style=dashed]
  node_ -> list_node [style=dashed]
  node_ -> format_node [style=dashed]
  list_node -> text_node [style=dashed]
  list_node -> format_node [style=dashed]
  format_node -> text_node [style=dashed]
   { rank=same; text_path text_symbolizer_helper }
   { rank=same; node_ TextSymbolizer}
}