is it possible to make a forest folder to grow both sides?

Question

I'm trying to save space in diagrams, so I want to know if there's an easy way to make a forest tree folder grow to right and left sides as seen in the image below

Currently I have this but I've no idea on how to manipulate growing of forest.

\documentclass{article}
\usepackage[letterpaper,margin=20mm]{geometry}
\usepackage{tikz}
\usepackage[edges]{forest}
\usepackage{xcolor}
\usetikzlibrary{shapes.geometric, arrows.meta, calc, patterns, patterns.meta, shadows}
\pgfkeys{/forest,
    rect/.append style={rectangle, rounded corners=2pt, /tikz/align=center},
}
\definecolor{background}{RGB}{239, 239, 239}
\definecolor{lightgreen}{RGB}{150, 240, 180}
\definecolor{green}{RGB}{146, 208, 80}
\definecolor{blue}{RGB}{4, 121, 181}
\definecolor{linecol}{RGB}{92, 92, 92}
\definecolor{lightpink}{RGB}{245, 160, 240}
\definecolor{lightblue}{RGB}{176, 221, 255}
\definecolor{lilac}{RGB}{174, 182, 211}
\begin{document}
\begin{figure}
    \centering
    \begin{forest}
        for tree={
            line width=0.5pt,
            draw=linecol,
            rect,
            calign=center,
            minimum size=25pt,
            text width=50mm,
            rounded corners=5pt,
            child anchor=north,
            parent anchor=south,
            drop shadow,
            l sep+=12.5pt,
            inner color=background,
            anchor=center,
            edge path={
                \noexpand\path[color=linecol, rounded corners=5pt,>={Stealth[length=10pt]}, line width=0.5pt, ->, \forestoption{edge}]
                (!u.parent anchor) -- +(0,-5pt) -|
                (.child anchor)\forestoption{edge label};
            },
            if = {level == 1}{outer color=lightblue, text width=38mm}{},
            if = {level == 2}{
                outer color=lightgreen,
                for tree = {
                    text width=28mm,
                    child anchor=west
                }
            }{},
            if = {level == 3}{outer color=lightpink, text width=12mm,}{}
        }
        [Clasificación, outer color=lilac,
        for tree = {
            for children = {
                grow'=0,
                folder
            }
        }
            [Térmicos
                [Adición
                    [MSF][MED][MVC][HDH][SD]
                ]
                [Extracción [Frz]]
            ]
            [Membrana
                [RO][FO][ED][NF]
            ]
            [Químicos
                [I.Ex][LLE][G. Hyd][Otros]
            ]
            [Adsorción]
        ]
    \end{forest}
\end{figure}
\end{document}

EDIT:

I think the solution could lie in the use of:

for children = {
    if={mod(n,2)==0}{circle}{}
}

But it doesn't appear to change when I use grow'=east nor grow'=west

[Adición,
    for children = {
        if={mod(n,2)==0}{
            for parent = {grow'=west}
        }{
            for parent = {grow'=east}
        }
    }
    [MSF][MED][MVC][HDH][SD]
]

_{^{And if it's possible, how to center "clasificación"}}

I have found interesting answers to this problem: Forest: different growing directions for branches on the same level and forest – grow half of tree the other direction — Eduardo Jiménez, Sep 09 '22 at 04:52
Did one of those answer your question and we should close as a duplicate? Or is there something remaining? (Or do you not remember by now!?) — cfr, Aug 09 '23 at 00:49
You can't have 2 growth directions for the same node. You have to fake it, if I remember correctly. There isn't a straightforward way that I know of, so it depends how much trouble you're prepared to go to to save space. I can show you a way to do it, if you want, but it may have unexpected results in other cases, for example, because forest may not know where things are. — cfr, Aug 15 '23 at 01:26
I think the multiple directions code could work if you're careful. Or you could create the smaller side elsewhere and then move it into position later. — cfr, Aug 15 '23 at 02:02
Just wondering why you allow so much width for the non-red boxes, if space is the issue, which probably is limited in horizontal direction? — MS-SPO, Dec 20 '23 at 07:09

score 4 · Accepted Answer · answered Dec 20 '23 at 03:09

I noticed that Sašo Živanović commented that one post contained the cleanest forest code on this site. This one certainly contains the filthiest. It uses an extremely mangled version of Sašo's answer. The mangling is partly a result of my not understanding the purpose of code and partly a product of my inability to modify it appropriately.

If it weren't for the fact nobody has answered this in well over a year, this answer would certainly be worthy of deletion. As it is, it surely deserves no better fate.

I've not drawn edges to the phantom children. Instead, I've modified their children's edges to draw from their grandparent. But something is very wrong with the way I've configured those children, since --- despite Sašo's positioning code, I still end up having to move them in before computing xy. Not only does this mean they are not accounted for when packing; all I've done is hard-code adjustments with no attempt to calculate anything because I don't understand why they end up where they do in the first place.

For what it's worth, I created a test document with a simple tree repeated over and over to experiment with different combinations of folder, grow/grow'/folder indent/l sep etc., but I still don't understand how to sensibly code a directory tree with the edge to the right of the children and a downward direction of growth. for tree={folder,grow=180} seems to work, so I used that, but dir subtree, grow subtree=180 did not produce similar results. This aspect of forest is simply beyond my ability to comprehend it.

\documentclass[varwidth=20cm,tikz,border=10pt]{standalone}
\usepackage[edges]{forest}
\usetikzlibrary{arrows.meta,shadows,ext.paths.ortho}
% ateb: https://tex.stackexchange.com/a/705346/
% addaswyd o ateb Sašo Živanović: https://tex.stackexchange.com/a/691730/
% addaswyd o gwestiwn Datboi: https://tex.stackexchange.com/q/691576/
\forestset{
  declare boolean={phantom child}{0},
  dir subtree/.style={%
    for tree={
      folder,
    },
    for descendants={
      edge path'/.expanded={
        (!uu.parent anchor) |- (.child anchor)
      },
    },
  },
  phantom children/.style={
    delay={
      for children={
        content/.option=!u.content,
        opacity=0,
        text opacity=0,
        draw,
        no edge,
        phantom child,
      },
    },
    after packing node={
      for children={
        l'=0pt,
        s'=0pt,
        get point anchor={\foresteoption{grow}+180}{l-}{s-},
      },
    },
  },
  grow subtree/.style={
    for tree={grow=#1}
  }, 
  grow' subtree/.style={
    for tree={grow'=#1}
  },
}
\makeatletter
% Analogous to \pgfpointanchor, but also allows forest anchors ("parent first"
% etc.)  and forest anchor options ("parent anchor" etc.) as #1.
\def\forestpointanchor#1{% #1 = anchor
  \forestanchortotikzanchor{#1}\forest@temp@anchor
  \forestoifdefined{@box}{%
    \forestoget{@box}\forest@temp
    \ifdefempty\forest@temp{%
      \forestpointanchor@callpgfpointanchor{name}%
    }{%
      \setbox0\hbox{%
        \begin{pgfpicture}%
          \forestpointanchor@callpgfpointanchor{later@name}%
        \end{pgfpicture}%
      }%
    }%
  }{%
    \forestpointanchor@callpgfpointanchor{name}%
  }%
  \forest@global@marshal
}
\def\forestpointanchor@callpgfpointanchor#1{% #1 = (later@)name
  \pgfpointanchor{\forestove{#1}}{\forest@temp@anchor}%
  \xdef\forest@global@marshal{%
    \global\pgf@x=\the\pgf@x\relax
    \global\pgf@y=\the\pgf@y\relax\relax
  }%
}
\csdef{forest@anchor@@}{\def\forest@temp@anchor{center}}%
\def\forestPointanchor#1#2{% #1 = node id, #2 = anchor
  \forest@fornode{#1}{\forestpointanchor{#2}}%
}
\forestset{
  % Get the coordinates of anchor #1
  % and assign the resulting x and y to keys #2 and #3, respectively.
  get point anchor/.code n args=3{%
    \forestpointanchor{#1}%
    \forestset{#2=\pgf@x,#3=\pgf@y}%
  },
}
\makeatother
\begin{document}
% cwestiwn Eduardo Jiménez:https://tex.stackexchange.com/q/650323/
\pgfkeys{/forest,
    rect/.append style={rectangle, rounded corners=5pt, /tikz/align=center},
    level outer colour/.style={outer color={level #1 outer colour}},
}
\definecolor{background}{RGB}{239, 239, 239}
\definecolor{lightgreen}{RGB}{150, 240, 180}
\definecolor{green}{RGB}{146, 208, 80}
\definecolor{blue}{RGB}{4, 121, 181}
\definecolor{linecol}{RGB}{92, 92, 92}
\definecolor{lightpink}{RGB}{245, 160, 240}
\definecolor{lightblue}{RGB}{176, 221, 255}
\definecolor{lilac}{RGB}{174, 182, 211}
\colorlet{level 0 outer colour}{lilac}
\colorlet{level 1 outer colour}{lightblue}
\colorlet{level 2 outer colour}{lightgreen}
\colorlet{level 3 outer colour}{lightpink}
\colorlet{level 4 outer colour}{lightpink}
\begin{forest}
  fork sep'=5pt,
  text width=50mm,
  for tree={
    rect,
    line width=0.5pt,
    draw=linecol,
    l sep'+=12.5pt,
  },
  before typesetting nodes={%
    where phantom child={%
    }{%
      level outer colour/.option=level,
      inner color=background,
      drop shadow,
      minimum size=25pt,
    },
  },
  for children={%
    text width=38mm,
    edge+={color=linecol, rounded corners=5pt,-{Stealth[length=10pt]}, line width=0.5pt},
    forked edge,
    for tree={%
      grow'=0,
      folder,
      if level=2{%
        text width=28mm,
      }{%
        if level=3{%
          text width=12mm,
        }{},
      },
    },
  },
  [Clasificación
      [Térmicos
        [Adición, phantom children,parent anchor=south
        [, dir subtree,for children={before computing xy={l'+=30pt}}
              [MSF][MED][MVC]
            ]
            [, dir subtree, grow subtree=180,for children={before computing xy={l'-=100pt}}
              [HDH][SD]
            ]
          ]
          [Extracción [Frz]]
      ]
      [,phantom,coordinate,calign with current]
      [Membrana
          [RO][FO][ED][NF]
      ]
      [Químicos
          [I.Ex][LLE][G. Hyd][Otros]
      ]
      [Adsorción]
  ]
\end{forest}
\end{document}

is it possible to make a forest folder to grow both sides?

1 Answers1