Tikz 箭头对齐

Question

我有一个关于 Tikz 环境中图形的问题，在下图中我想将传入和传出箭头分开，并将每对传入和传出箭头设为水平线。请指导我如何做到这一点？

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes,shadows,arrows,positioning}

\tikzset{
line/.style={draw,-stealth,thick},
block/.style={draw,rectangle, text width=10em, text centered, minimum height=15mm, node distance=10em}
}

%fill=yellow!50
\begin{document}

\begin{tikzpicture}
\node [block] (browser) {BROWSER};
\node [block, below of= browser] (mediaplayer) {MEDIA PLAYER};  
\node [block, right of= browser,node distance= 30em, yshift=-50pt, minimum height=20em] (webserver) {WEB SERVER};  

%arrows
\path [line] (browser) -- (webserver);
\path [line] (webserver) -- (browser);

\path [line] (browser) -- (mediaplayer);

\path [line] (mediaplayer) -- (webserver);
\path [line] (webserver) -- (mediaplayer);

\end{tikzpicture}

\end{document}

Answer 1

一个简单的解决方案，线条不太平行

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes,shadows,arrows,positioning}

\tikzset{
line/.style={draw,-stealth,thick},
block/.style={draw,rectangle, text width=10em, text centered, minimum height=15mm, node distance=10em}
}

%fill=yellow!50
\begin{document}

\begin{tikzpicture}
\node [block] (browser) {BROWSER};
\node [block, below of= browser] (mediaplayer) {MEDIA PLAYER};  
\node [block, right of= browser,node distance= 30em, yshift=-50pt, minimum height=20em] (webserver) {WEB SERVER};  

%arrows
\path [line] (browser.-3) -- (browser.-3-|webserver.west);
\path [line,red] (webserver.west|-browser.3) |- (browser.3);

\path [line] (browser) -- (mediaplayer);

\path [line] (mediaplayer.-3) -- (mediaplayer.-3-|webserver.west);
\path [line,green] (webserver.west|-mediaplayer.3) -- (mediaplayer.3);

\end{tikzpicture}

\end{document}