Kdtyjb

I know that nesting tikz pictures is considered bad, but I did it anyway as I don't want to mess around with manual positioning. I'm nesting several rectangles similar to another question for circles. The problem is that the rectangles aren't centered correctly, which can be seen at the left and right stacking vertical lines.

Is this a problem caused by nesting or am I doing something different wrong?

documentclass{article}



usepackage{tikz}

usetikzlibrary{positioning}



begin{document}

begin{tikzpicture}[

    class/.style={

      draw,

      align=center,

      rectangle,

      rounded corners=20pt,

      minimum size=0pt,

      inner sep=5pt,

      outer sep=0pt,

    },

    label/.style={

      rectangle,

      align=center,

      inner sep=6pt,

      outer sep=4pt, % shifts labels a bit down

      node distance=0pt,

    },

  ]



  node [class] (csl) {

    begin{tikzpicture}

      node [class] (ptime) {

        begin{tikzpicture}

          node [class] (mcfl) {

            begin{tikzpicture}

              node [class] (rpl) {

                begin{tikzpicture}

                  node [class] (tal) {

                    begin{tikzpicture}

                      node [class,rounded corners=5pt] (cfl) {CFG};

                      node [label, below=of cfl] {TAG, LIG, CCG, HG };

                    end{tikzpicture}

                  };

                  node [label, below=of tal] {RPG, (2,2)-MCFG};

                end{tikzpicture}

              };

              node [label, below=of rpl] {MCFG, LCFRS};

            end{tikzpicture}

          };

          node [label, below=of mcfl] {RCG, simple LMG \ (= PTIME)};

        end{tikzpicture}

      };

      node [label, below=of ptime] {CSG};

    end{tikzpicture}

  };



end{tikzpicture}

end{document}

Compare the code below with yours. There is still room for improvements.

documentclass{article}



usepackage{tikz}

usetikzlibrary{positioning}

usetikzlibrary{backgrounds,fit}

tikzset{every fit/.append style=text badly centered}

tikzset{class/.style={

      draw,

      rectangle,

      rounded corners=20pt,

      inner ysep=5pt,

    },

        label/.style={

      align=center,

      inner sep=6pt,

      outer ysep=4pt,

      node distance=0pt,

    }

}





begin{document}

begin{tikzpicture}



node [class,rounded corners=5pt] (cfl) {CFG};

node [label, below=of cfl] (tal) {TAG, LIG, CCG, HG };

node [label, below=of tal] (rpl) {RPG, (2,2)-MCFG};

node [label, below=of rpl] (mcfl) {MCFG, LCFRS};

node [label, below=of mcfl] (ptime) {RCG, simple LMG \ (= PTIME)};

node [label, below=of ptime] (csl) {CSG};



begin{pgfonlayer}{background}

    node [class, inner xsep=5em, fit=(cfl) (tal) (rpl) (mcfl) (ptime) (csl)] {};

    node [class, inner xsep=4em, fit=(cfl) (tal) (rpl) (mcfl) (ptime)] {};

    node [class, inner xsep=3em, fit=(cfl) (tal) (rpl) (mcfl)] {};

    node [class, inner xsep=2em, fit=(cfl) (tal) (rpl)] {};

    node [class, inner xsep=1em, fit=(cfl) (tal)] {};

end{pgfonlayer}



end{tikzpicture}

end{document}