Adjusting the starting coordinates of an arrow precisely inside a TikZ node

Question

I have difficulty adjusting the starting coordinates of the arrow line inside a TikZ node:

When I try to make the starting vertical coordinate of the last arrow which is beneath the mid point of the node, a bit higher vertically by subtracting 0.1 like so:

\draw[*-{Stealth},very thick] let \p1 = (B.two), \p2 = (B.center) in (\x1+\nodewidth * 0.10, \y2 -0.1) |- (C);

the starting point jumps above the mid point:

I have tinkered with several other options but still I couldn't position the starting points into the mid point of the node.

The code is just a bit long but it's compiled fine.

% compile with lualatex 
\documentclass[a4paper,openany,14pt]{extbook}

\usepackage{tikz}
\usetikzlibrary{shapes.multipart,chains,positioning,arrows,calc}

\usetikzlibrary{arrows.meta}
\tikzset{*->stealth}

\usetikzlibrary{fit}

\usepackage{xparse}

\makeatletter % get the dimensions of the box (node) which was formed prior
\NewDocumentCommand {\getnodedimen} {O {\nodewidth} O {\nodeheight} m} {
  \begin{pgfinterruptboundingbox}
  \begin{scope}[local bounding box=bb@temp]
    \node[inner sep=0pt, fit=(#3)] {};
  \end{scope}
  \path ($(bb@temp.north east)-(bb@temp.south west)$);
  \end{pgfinterruptboundingbox}
  \pgfgetlastxy{#1}{#2} }
\makeatother

\usepackage{fontspec}
\usetikzlibrary{matrix}

\newcommand{\columnratio}{0.62}
\newcommand{\columnseper}{12pt}

\begin{document}

\pgfmathsetlengthmacro{\ourwidth}{\columnratio * \linewidth - \columnseper}

\tikzset{kutu/.style = {rectangle split, rectangle split horizontal,rectangle split parts=2, very thick,draw=black!100, align=center,font=\footnotesize, text width=0.047 * \ourwidth,minimum width=0.040 * \ourwidth, text height=0.023 * \ourwidth,text depth=2.7pt,inner xsep=0.27cm,}} % kutu is the turkish word for "box"

\noindent\begin{tikzpicture}[start chain=1 going right,start chain=2 going right]
\tikzset{every node}=[font=\small\ttfamily]
      
\node[rectangle, on chain=1,inner xsep=0.05cm,](ORIG){\footnotesize 1511};
\node[kutu,on chain=1,right=0.0cm of ORIG] (A) 
     {\nodepart[]{one}1111 \nodepart[]{two}};

\node[kutu, on chain=1,right=0.4cm of A,] (B)
     {\nodepart[]{one} \nodepart[]{two}};

\node[kutu, on chain=1,right=0.4cm of B] (C)
     {\nodepart[]{one}2111 \nodepart[]{two}};

\node[kutu, on chain=2,below=0.8cm of B] (D) at (6.0, -0.5)
     {\nodepart[]{one}3422 \nodepart[]{two}};
     
\getnodedimen{A} % we extract the dimensions of the box we just formed, in order to position
                 % the starting coordinate of the arrow line. It gives as output the "nodewidth"

 \draw[*-{Stealth},very thick] let \p1 = (A.two), \p2 = (A.center) in (\x1+\nodewidth * 0.10, \y2) -- (B);
 \draw[*-{Stealth},very thick] let \p1 = (B.one), \p2 = (B.center) in (\x1+\nodewidth * 0.10, \y2) |- (D);
 \draw[*-{Stealth},very thick] let \p1 = (B.two), \p2 = (B.center) in (\x1+\nodewidth * 0.10, \y2) |- (C);
\end{tikzpicture}
\end{document}

How to adjust the starting points of the arrow lines precisely so that they are aligned into the mid and center points inside the TikZ node ?

UPDATE After applying this code

 \draw[very thick,red,{Circle[length=6pt,sep=-3pt]}-{Stealth}] ($(B.west)!0.25!(B.east)$) |- (D.west);
 \draw[very thick,red,{Circle[length=6pt,sep=-3pt]}-{Stealth}] ($(B.two)$) |- (C.west);

upon daleif 's comment, the situation improved greatly:

As such, that comment solves the problem but what is the ($(B.west)!0.25!(B.east)$) notation exactly? It looks like the math notation of TeX but I assume the expression inside $ s does arithmetic / calculates values when used whithin the context of TikZ, is that right?

Answer 1

With use of the chains library and define arrows start position by perpendicular coordinate systems:

\documentclass[border=3.141592,tikz]{standalone}
\usetikzlibrary{arrows.meta, 
                chains,
                positioning,
                shapes.multipart}

\begin{document}
    \begin{tikzpicture}[
node distance = 8mm and 8mm,
  start chain = A going right,
   box/.style = {rectangle split, rectangle split horizontal,
                 rectangle split parts=2,
                 draw, thick,
                 text width=3em, minimum height=3ex, 
                 align=center},
   arr/.style = {draw=#1, thick,
                 {Circle[length=6pt,sep=-3pt]}-{Stealth[width=6pt]}
                },
   arr/.default = red
                    ]
% nodes
    \begin{scope}[nodes={on chain=A}]
\node       {1511};                     % A-1
\node[box]  { 1111 \nodepart{two} };
\node[box]  {      \nodepart{two} };
\node[box]  { 2111 \nodepart{two} };    % A-4
    \end{scope}
\node[box, below=of A-4] (A-5) {3422 \nodepart{two} };
% arrows
\path[arr=black]
            (A-2.two north |- A-2.east) -- (A-3);
\path[arr]  (A-3.two north |- A-3.east) -- (A-4);
\path[arr]  (A-3.one north |- A-3.west) |- (A-5);
    \end{tikzpicture}
\end{document}

Addendum: Regarding to your comments:

• You should provide this requirements already in question. It si not contain requirements for possibilities of changes node size (and eventually distances between them).

• Conditionality for accepting this answer only if I comply with your new requirements in the answer is not polite (actually is unacceptable).

• Anyway, on image size can be influenced on many ways:

  • by scaling of image (not recommended, font size become inconsistent)
  • by changing node distance between nodes
  • \nptw (node part text width) for text width in box style
  • both aforementioned options you can define after tikzpicture image
  • adding option for font size (if you need for example smaller fonts

Adopted MWE to this requirements can be:

\documentclass[border=3.141592,tikz]{standalone}
\usetikzlibrary{arrows.meta,
                chains,
                positioning,
                shapes.multipart}
\tikzset{mystyles/.style = {
  start chain = A going right,
   box/.style = {rectangle split, rectangle split horizontal,
                 rectangle split parts=2,
                 draw, thick,
                 text width=\nptw, minimum height=3ex, inner sep=2pt,
                 align=center},
   arr/.style = {draw=#1, thick,
                 {Circle[length=6pt,sep=-3pt]}-{Stealth[width=6pt]}
                },
   arr/.default = red}
        } % end of tikzset

\begin{document}
    \begin{tikzpicture}[mystyles,
         font = \scriptsize,    % change to desired size
node distance = 5mm and 4mm,    % <---
                        ]
\def\nptw{2em}                  % <--- define box cells width
% nodes
    \begin{scope}[nodes={on chain=A}]
\node       {1511};                     % A-1
\node[box]  { 1111 \nodepart{two} };
\node[box]  {      \nodepart{two} };
\node[box]  { 2111 \nodepart{two} };    % A-4
    \end{scope}
\node[box=\nptw, below=of A-4] (A-5) {3422 \nodepart{two} };
% arrows
\path[arr=black]
            (A-2.two north |- A-2.east) -- (A-3);
\path[arr]  (A-3.two north |- A-3.east) -- (A-4);
\path[arr]  (A-3.one north |- A-3.west) |- (A-5);
    \end{tikzpicture}
\end{document}

Answer 2

This should help you reach your goal:

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows.meta}
\usetikzlibrary{calc}
\usetikzlibrary{positioning}
\usetikzlibrary{shapes.multipart}

\begin{document}
\begin{tikzpicture}[
    node distance=1cm,
    box/.style={
        draw, thick,
        rectangle split,
        rectangle split horizontal,
        rectangle split parts=2,
        text width=1.25cm,
        minimum height=.65cm,
        inner sep=0pt,
        align=center
    },
    arrow/.style={
        thick,
        {Circle[length=6pt,sep=-3pt]}-{Stealth[width=6pt]}
    }
]
    % nodes
    \node (ORIG) {1511};
    \node[box, right=.25cm of ORIG] (A) {
        1111 \nodepart{two}
    };
    \node[box, right=of A] (B) {
        \nodepart{two}
    };
    \node[box, right=of B] (C) {
        2111 \nodepart{two}
    };
    \node[box, below=of B, anchor=west] (D) {
        3422 \nodepart{two}
    };

    % arrows
    \draw[arrow] ($(A.west)!.75!(A.east)$) -- (B.west);
    \draw[arrow, red] ($(B.west)!.25!(B.east)$) |- (D.west);
    \draw[arrow, red] ($(B.west)!.75!(B.east)$) -- (C.west);

    % added to show how two entries can be used
    \node[box, right=of D, blue] (E) {
        A \nodepart{two} B
    };
    \draw[arrow, blue] ($(D.west)!.75!(D.east)$) -- (E.west);
\end{tikzpicture}
\end{document}