带有 faIcon 和箭头定位的标签

Question

1. 我怎样才能让（上方和下方）箭头彼此靠近一点？以及
2. 如何将标签放在 \faIcon 符号下？

\documentclass[a4paper]{scrartcl}
\usepackage{amsmath,amssymb,amsfonts}
\usepackage{tikz}
\usepackage{tikz-uml}
\usetikzlibrary{shapes.multipart,positioning,fit}
\usepackage{pgf-umlsd}
\usetikzlibrary{arrows}
\usepackage{fontawesome}

\begin{document}
\begin{tikzpicture}
\node[scale=2.2]                        (A) at (0,0)        {\faUser};
\node[scale=2,right=0.75cm of A]        (B) at (A.east)     {\faInstitution};
\node[scale=2,right=0.75cm of B]        (C) at (B.east)     {\faInstitution};
        
\draw[gray,->] (A.north east)  --  (B.north west) node[midway, above]{\tiny{AA}}; 
\draw[gray,->] (B.north east)  --  (C.north west) node[midway, above]{\tiny {BB}}; ; 
\draw[gray,<-] (A.south east)  --  (B.south west) node[midway, below]{\tiny {CC}}; ; 
\draw[gray,<-] (B.south east)  --  (C.south west) node[midway, below]{\tiny {DD}}; ; 
\end{tikzpicture}
\end{document} 

Answer 1

通过使用更多的库和样式定义，图像代码变得更加简单：

\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,    % <--- changed
                chains,         % <--- new
                positioning,
                quotes}         % <--- new
\usepackage{newtxtext, 
            fontawesome}

\begin{document}
    \begin{tikzpicture}[
node distance = 9mm,
  start chain = going right,
         N/.style = {inner ysep=0pt, font=\Huge, on chain},
        tc/.style = {transform canvas={yshift=#1}},
every label/.style= {font=\tiny, text=red},
every edge/.style = {draw, gray, -Straight Barb},
every edge quotes/.style = {auto, inner sep=1pt, font=\tiny}
                        ]
\node[N,label=below:USER ] (A) {\faUser};
\node[N,label=below:ORG 1] (B) {\faInstitution};
\node[N,label=below:ORG 2] (C) {\faInstitution};
%
\draw[tc=+1ex]   
        (A)  edge ["AA"]    (B)
        (B)  edge ["BB"]    (C);
\draw[tc=-1.2ex]
        (C)  edge ["AA"]    (B)
        (B)  edge ["BB"]    (A);
\end{tikzpicture}
\end{document}

Answer 2

请确保你的例子是最小的以及工作；你当前的示例对我来说编译不通过。我尝试制作一个在职的举个例子来说明你提出的问题。如果你还想了解更多信息，请随时告诉我。

\documentclass[tikz]{standalone}
\usetikzlibrary{positioning}
\usepackage{fontawesome}

\begin{document}
\begin{tikzpicture}[label distance=-1em,every node/.style={font=\tiny}]
  \node[scale=3.2,label=below:{USER}]
  (A) at (0,0)
  {\faUser};
  \node[scale=3,right=2em of A,label=below:{ORG1}]
  (B) at (A.east)
  {\faInstitution};
  \node[scale=3,right=2em of B,label=below:{ORG2}]
  (C) at (B.east)
  {\faInstitution};
  \draw[gray,->] (A.25)--(B.157)
  node[midway, above]{AA};
  \draw[gray,->] (B.25)--(C.155)
  node[midway, above]{BB};
  \draw[gray,<-] (A.335)--(B.203)
  node[midway, below]{CC};
  \draw[gray,<-] (B.335)--(C.205)
  node[midway, below]{DD};
\end{tikzpicture}
\end{document}