我对两个 tikzpicture 环境的对齐存在问题。
\documentclass[14pt,spanish]{extarticle}
\usepackage{fontspec}
\setmainfont[Mapping=tex-text]{Ubuntu}
\usepackage{geometry}
\geometry{verbose,tmargin=2cm,bmargin=2cm,lmargin=2cm,rmargin=2cm}
\usepackage{subscript}
\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{textgreek}
\usepackage{mhchem}
\usetikzlibrary{shapes.geometric, arrows}
\tikzstyle{inicio} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=yellow]
\tikzstyle{nodo} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black]
\tikzstyle{arrow} = [thick,->,>=stealth]
\makeatother
\usepackage{babel}
\addto\shorthandsspanish{\spanishdeactivate{~<>}}
\usepackage{xunicode}
\begin{document}
\begin{figure}[h!]
\centering
\begin{tikzpicture}[node distance=2cm]
\node (fosforo) [inicio] {Fósforo};
\node (ortofosfato) [nodo, below of=fosforo] {Ortofosfato (\ce{P-PO_4^{3-}})}; \draw [arrow] (fosforo) -- node [anchor=west] {medido como} (ortofosfato);
\end{tikzpicture}
\end{figure}
\begin{figure}[h!]
\centering
\begin{tikzpicture}[node distance=2cm]
\node (nitrogeno) [inicio] {Nitrógeno};
\node (nitrato) [nodo, below of=nitrogeno, xshift=-2.5cm] {Nitrato (\ce{N-NO_3^{-}})}; \draw [arrow] (nitrogeno) -- node [anchor=east,xshift=-0.5cm] {medido como} (nitrato);
\node (amonio) [nodo, below of=nitrogeno, xshift=2.5cm] {Amonio (\ce{N-NH_4^+})}; \draw [arrow] (nitrogeno) -- node [anchor=west,xshift=0.5cm] {medido como} (amonio);
\end{tikzpicture}
\end{figure}
\end{document}
我希望节点“fosforo”和“nitrogeno”在页面中心水平对齐。我该怎么做？
答案1
您的顶部节点位于 的中心(0,0)，因此您可以使用trim left和trim right使图片关于此轴对称。由于同一行上没有其他内容，因此足以使图片宽度为零。因此，您可以添加
trim left=0pt,trim right=0pt
作为这些图片的选项。下面我centerzero为此定义了一种样式：
\documentclass[14pt,spanish]{extarticle}
\usepackage{fontspec}
%\setmainfont[Mapping=tex-text]{Ubuntu}
\usepackage{geometry}
\geometry{verbose,tmargin=2cm,bmargin=2cm,lmargin=2cm,rmargin=2cm}
\usepackage{subscript}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{textgreek}
\usepackage{mhchem}
\usetikzlibrary{shapes.geometric, arrows}
\tikzstyle{inicio} = [rectangle, rounded corners, minimum width=3cm,
minimum height=1cm,text centered, draw=black, fill=yellow]
\tikzstyle{nodo} = [rectangle, rounded corners, minimum width=3cm,
minimum height=1cm,text centered, draw=black]
\tikzstyle{arrow} = [thick,->,>=stealth]
\tikzstyle{centerzero} = [trim left=0pt,trim right=0pt]
\usepackage{babel}
\addto\shorthandsspanish{\spanishdeactivate{~<>}}
\usepackage{xunicode}
\begin{document}
\begin{figure}[htp]
\centering
\begin{tikzpicture}[node distance=2cm,centerzero]
\node (fosforo) [inicio] {Fósforo};
\node (ortofosfato) [nodo, below of=fosforo] {Ortofosfato
(\ce{P-PO_4^{3-}})};
\draw [arrow] (fosforo) -- node [anchor=west] {medido como}
(ortofosfato);
\end{tikzpicture}
\end{figure}
\begin{figure}[htp]
\centering
\begin{tikzpicture}[node distance=2cm,centerzero]
\node (nitrogeno) [inicio] {Nitrógeno};
\node (nitrato) [nodo, below of=nitrogeno, xshift=-2.5cm]
{Nitrato (\ce{N-NO_3^{-}})};
\draw [arrow] (nitrogeno) -- node [anchor=east,xshift=-0.5cm]
{medido como} (nitrato);
\node (amonio) [nodo, below of=nitrogeno, xshift=2.5cm]
{Amonio (\ce{N-NH_4^+})};
\draw [arrow] (nitrogeno) -- node [anchor=west,xshift=0.5cm]
{medido como} (amonio);
\end{tikzpicture}
\end{figure}
\end{document}
或者，如果你想确保这个图形有一个固定的非零宽度，你可以把
trim left=-8cm,trim right=8cm
使中间水平方向tikzpicture宽16厘米。(0,0)
顺便说一句，您制作的这些figures 带有放置选项h!，但没有标题。如果您只想要当前位置的图片（没有标题），那么环境center更合适。
答案2
我将两个 tikzpicture 放在一个图形环境中。这样它们就并排放置了。我在图形前后添加了垂直空间，使其垂直居中。
\documentclass[14pt,spanish]{extarticle}
\usepackage{fontspec}
\setmainfont[Mapping=tex-text]{Ubuntu}
\usepackage{geometry}
\geometry{verbose,tmargin=2cm,bmargin=2cm,lmargin=2cm,rmargin=2cm}
\usepackage{subscript}
\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{textgreek}
\usepackage{mhchem}
\usetikzlibrary{shapes.geometric, arrows}
\tikzstyle{inicio} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=yellow]
\tikzstyle{nodo} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black]
\tikzstyle{arrow} = [thick,->,>=stealth]
\makeatother
\usepackage{babel}
\addto\shorthandsspanish{\spanishdeactivate{~<>}}
\usepackage{xunicode}
\begin{document}
\vspace*{\fill}
\begin{figure}[h!]
\centering
\begin{tikzpicture}[node distance=2cm]
\node (fosforo) [inicio] {Fósforo};
\node (ortofosfato) [nodo, below of=fosforo] {Ortofosfato (\ce{P-PO_4^{3-}})}; \draw [arrow] (fosforo) -- node [anchor=west] {medido como} (ortofosfato);
\end{tikzpicture}
%\end{figure}%
%\begin{figure}[h!]
% \centering
\begin{tikzpicture}[node distance=2cm]
\node (nitrogeno) [inicio] {Nitrógeno};
\node (nitrato) [nodo, below of=nitrogeno, xshift=-2.5cm] {Nitrato (\ce{N-NO_3^{-}})}; \draw [arrow] (nitrogeno) -- node [anchor=east,xshift=-0.5cm] {medido como} (nitrato);
\node (amonio) [nodo, below of=nitrogeno, xshift=2.5cm] {Amonio (\ce{N-NH_4^+})}; \draw [arrow] (nitrogeno) -- node [anchor=west,xshift=0.5cm] {medido como} (amonio);
\end{tikzpicture}
\end{figure}
\vfill
\end{document}