TikZ-PGF – Minimum Height in Split Rectangle

tikz-pgf

I have a split rectangle node, and I would like either for the entire node to be a certain height, with the splits spread equally, or each nodepart to be a certain height. I have the following code, in which only the first part is stretched, how can I apply this to all nodeparts?

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}

\begin{tikzpicture}[auto,
    rect/.style={
        rectangle split,
        rectangle split parts=4,
        draw=black,
        rounded corners, 
        text width=7cm,
        text height=3cm
    }]  


    % Split Rectangle
    \node [rect] {
        First Item
        \nodepart{two} Second Item
        \nodepart{three} $\vdots$
        \nodepart{four}  Last Item
        };

\end{tikzpicture}
\end{document}

enter image description here

Best Answer

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}
  \def\mystrut{\vrule height 1.5cm depth 1.5cm width 0pt} 

 \begin{document}    

   \begin{tikzpicture}[auto,
    rect/.style={
        rectangle split,
        rectangle split parts=4,
        draw=black,
        rounded corners
    }]  


    % Split Rectangle
    \node [rect] {
      \mystrut  First Item
        \nodepart{two}\mystrut Second Item
        \nodepart{three} $\vdots$
        \nodepart{four} \mystrut Last Item
        };

\end{tikzpicture}
\end{document}

enter image description here

Code

\documentclass{article}
\usepackage{tikz,calc}
\usetikzlibrary{shapes}
\tikzset{
    data/.style={
        draw,
        rectangle split,
        rectangle split parts=2,
        text centered,
    },
    data+/.style={
        data,
        rectangle split every empty part={},% resets empty-part macro (explanation below)
        rectangle split empty part width=\widthof{#1},
        rectangle split empty part height=\heightof{#1},
        rectangle split empty part depth=\depthof{#1},
    },
}
\newcommand{\data}{data \nodepart{second} \phantom{null}}
\begin{document}
\begin{tikzpicture}[node distance=2cm]
    \node [data+={null}]        (A)    {data};
    \node [data, right of=A]    (B)    {\data};
    \node [data, right of=B]    (C)    {data \nodepart{second} null};
\end{tikzpicture}
\end{document}

Output

enter image description here

Excursus: `-1ex`

The definition of the data+ style was previously

data+/.style={
    data,
    rectangle split empty part width=\widthof{#1}-1ex,
    rectangle split empty part height=\heightof{#1},
    rectangle split empty part depth=\depthof{#1},
},

The OP rightly asks

[W]hy do you have to subtract 1ex from the width?

PGF/TikZ has one special macro that is inserted for an empty node-part if /pgf/rectangle split ignore empty parts is false(which seems to be the default contrary to the PGF manual), otherwise we wouldn’t even get a box.
The name of this macro is \pgf@lib@sh@rs@every@emptypart (for short: empty-part macro).

One would expect that PGF stores away the lengths given to rectangle split empty part <width|height|depth> keys and does not build this macro with the latest dimensions until it is needed. But this is not the case.
Every time rectangle split empty part <width|height|depth> is used a rule of the given width, height or depth is created and added to the empty-part macro (all other length parameters of that rule are 0pt, meaning they are invisible (e.g. \strut)).

The problem arises that rules (even invisible ones) are getting stacked horizontally. Rules with a height or depth do not get stacked vertically so they don’t accumulate extra height/depth, but rules with a width (horizontal rules) accumulate.

But wait! We only used those keys once! Yes, but no.
As a matter of fact they are used once before, namely during the initialization.
The file pgflibraryshapes.multipart.code.tex reads on lines 370, 378 and 386:

rectangle split empty part width=1ex,%  line 370
rectangle split empty part height=1ex,% line 378
rectangle split empty part depth=0ex,%  line 386

When we start we have a square box of 1ex × 1ex. If we add a vertical rule of 2ex we get a box of 1ex × 2ex, but if we add a horizontal rule of 2ex we get a box of 3ex × 1ex.

A picture worth than thousand words?

I constructed an example, where

the initial box is empty:

\def\pgf@lib@sh@rs@every@emptypart{}% clean slate

and the rules have actually a “width” (orthogonal to its “length”), i.e. a horizontal rule has a height (actually a height and a depth so that the middle of the line lies on the baseline), and a vertical rule has a width.

Not-MWE

rs width is a short-cut for rectangular split empty parts width, the same holds for rs height and rs depth.

\node[rectangle split ignore empty parts=false]                                          (a) {a};
\node[right of=a,  rs width =  1ex]                                                      (b) {b};
\node[right of=b, rs height =  3ex]                                                      (c) {c};
\node[right of=c,  rs depth = .5ex]                                                      (d) {d};
\node[below of=a,   rs width = 1ex,  rs width = \widthof{null}]           [yshift=-.5cm] (e) {e};
\node[right of=e,  rs height = 1ex, rs height = 2ex, rs height = .5ex]                   (f) {f};
\node[right of=f,   rs depth = 1ex,  rs depth = 2ex,   rs depth = 3ex]                   (g) {g};
\node[right of=g,   rs width = 1ex,  rs depth = 2ex,  rs height = 1ex, rs width = 2.5ex] (h) {h};

Output

The rules are:

baseline: black
horizontal (width): red
vertical (height): green
vertical (depth): blue

enter image description here

Is there a better solution?

Two come to mind:

instead of subtracting hard-coded 1ex we could subtract the current actual width
```
rectangle split empty part width=\widthof{#1}-\widthof{\pgf@lib@sh@rs@every@emptypart}
```
which would work quite okay as long as its content is not wider than #1.
Overwriting the empty-part macro.

There is a undocumented key rectangle split every empty part that is not used once in PGF and TikZ. Its definition is

rectangle split every empty part/.store in=\pgf@lib@sh@rs@every@emptypart

We cannot do rectangle split every empty part={\phantom{null}} because TikZ switched to a \nullfont that swallows everything. (Have you ever tried to just write something in a tikzpicture environment?). This is the same reason, I used calc’s \<dimen>of macros, they escape this cleverly.

We could fill this empty part macro with rules (not again!) overwriting any existing content, but then we could just use our old solution without -1ex by just removing any content.

Code

\tikzset{
    data+/.style={
        data,
        rectangle split every empty part={},% resets empty-part macro
        rectangle split empty part width=\widthof{#1},
        rectangle split empty part height=\heightof{#1},
        rectangle split empty part depth=\depthof{#1},
    },
}

[Tex/LaTex] How to define the default vertical distance between nodes

I don't really get the question so I hope this is what you wanted. If you include a full document (such that we copy paste and see the problem on our systems) things are much more easier.

Here, you can change the default setting within a scope but your block style had a node distance which was resetting every time it is issued. I've made it 2mm such that we can see the difference easier.

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows,shapes.geometric,positioning}

\begin{document}
\begin{tikzpicture}[decision/.style={diamond, draw, text width=4.5em, text badly centered, node distance=3.5cm, inner sep=0pt},
                    block/.style   ={rectangle, draw, text width=6em, text centered, rounded corners, minimum height=4em, minimum height=2em},
                    cloud/.style   ={draw, ellipse, minimum height=2em},
                    line/.style    ={draw,-latex'},
                    node distance = 1cm, 
                    auto]
    \node [block] (1st) {1st};
    \node [block, right= of 1st]  (2nd1) {2nd1};
\begin{scope}[node distance=2mm and 10mm]%Here we change it for everything inside this scope
    \node [block, above= of 2nd1] (2nd2) {2nd2};
    \node [block, below= of 2nd1] (2nd3) {2nd3};
    \node [block, right= of 2nd1] (3rd1) {3rd1};
    \node [block, above= of 3rd1] (3rd2) {3rd2};
    \node [block, above= of 3rd2] (3rd3) {3rd3};
\end{scope}
    \node [block, below= of 3rd1] (3rd4) {3rd4};
    \node [block, below= of 3rd4] (3rd5) {3rd5};

    \path [line] (1st) -- (2nd1);
    \path [line] (2nd1) -- (2nd2);
    \path [line] (2nd1) -- (2nd3);
    \path [line] (2nd2) -- (3rd3);
    \path [line] (2nd1) -- (3rd1);
    \path [line] (1st) -- (2nd1);
\end{tikzpicture}
\end{document}

enter image description here

Best Answer

Related Solutions

tikz-pgf – Create TikZ Rectangle Split Parts with Fixed Height

Code

Output

Excursus: -1ex

A picture worth than thousand words?

Not-MWE

Output

Is there a better solution?

Code

[Tex/LaTex] How to define the default vertical distance between nodes

Related Question

Excursus: `-1ex`