行间隔内的标记

Question

我正在尝试使用一些注释来创建行间隔，但发现自己对节点和位置的调整过多了。有没有更聪明的方法来完成这类工作？另外，我很恼火的是 $f$ 不在标记下方，导致箭头不平衡。我无法对齐[below]并[left]使用不同的间距。

任何提示都非常受欢迎

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows,shapes,svg.path}
\begin{document}
  \begin{tikzpicture}[x=2cm]
    \pgfmathsetmacro\N{int(5)};
    \pgfmathsetmacro\Nm{int(\N-1)}; 
    \pgfmathsetmacro\Nmm{int(\N-2)};

    % Draw the number line 
    \draw (0,0) -- (\Nmm,0);
    \draw [dotted] (\Nmm,0) -- (\Nm,0);
    \draw (\Nm,0) -- (\N,0);

    % Regular grid
    \foreach \i in {0,...,\Nmm} {
        \draw (\i,0.1) -- + (0,-0.2) node[below] {\small $x_\i$};
   }
    \draw(\Nm,0.1) -- + (0,-0.2) node[below] {\small $x_{N-1}$};
    \draw(\N,0.1) -- + (0,-0.2) node[below] {\small $x_{N}$};

    % Distance h
    \draw [|-] (0,.5) -- (0.35,.5) node[right] {$h$};
    \draw [-|] (.60,.5) -- (1,.5);

    % Staggered Grid 
    \foreach \i in {1,...,\Nmm} {
        \pgfmathsetmacro\j{int(2*\i-1)};
        \draw (\i-.5,0.1) -- +(0,-0.2) node[below] {\small $x_\frac{\j}{2}$};
   }
    \draw (\N-.5,0.1) -- + (0,-0.2) node[below]{\small $_{N-\frac{1}{2}}$};

    % Vector functions
    \foreach \i in {0,...,\N} { 
      \draw [red, fill=red,opacity=.3] (\i,0) circle (1mm) node[above=1cm,style={black,opacity=100}] {\small $\mathbf{v}$};
   }

    % Dv
    \foreach \i in {1,...,\Nmm} { 
        \pgfmathsetmacro\j{int(2*\i-1)};
        \draw (\i-.5,0) -- + (0,0) node[above=1cm] {\small $\mathbf{D}\mathbf{v}$};
        \draw [->,opacity=.3,thick] (\i-.9,1.25) -- (\i-.7,1.25);
        \draw [->,opacity=.3,thick] (\i-.1,1.25) -- (\i-.3,1.25);
    }
    \draw (\N-.5,0.0) -- + (0,-0.0) node[above=1cm] {\small $\mathbf{D}\mathbf{v}$};
    \draw [->,opacity=.3,thick] (\N-.9,1.25) -- (\N-.7,1.25);
    \draw [->,opacity=.3,thick] (\N-.1,1.25) -- (\N-.3,1.25);

    % Scalar functions
    \foreach \i in {1,...,\Nmm} { 
        \pgfmathsetmacro\j{int(2*\i-1)};
        \draw [blue,fill=blue,opacity=.2] (\i-.55,-.1) rectangle (\i-.45,.1) node[below=1cm, style={black,opacity=1}] {\small $f$};
        \draw [->,opacity=.3,thick] (\i-.55,-1.25) -- (\i-.80,-1.75);
        \draw [->,opacity=.3,thick] (\i-.35,-1.25) -- (\i-.20,-1.75);
    }
    \draw [blue,fill=blue,opacity=.2] (\N-.55,-.1) rectangle (\N-.45,.1) node[below=1cm, style={black,opacity=1}] {\small $f$};
    \draw [->,opacity=.3,thick] (\N-.55,-1.25) -- (\N-.80,-1.75);
    \draw [->,opacity=.3,thick] (\N-.35,-1.25) -- (\N-.20,-1.75);
    \draw [blue,fill=blue,opacity=.2] (-.05,-.1) rectangle (.05,.1) node[below=1cm, style={black,opacity=1}] {\small $f$};
    \draw [->,opacity=.3,thick] (0.01,-1.45) -- (.01,-1.75);
    \draw [blue,fill=blue,opacity=.2] (\N-.05,-.1) rectangle (\N+.05,.1) node[below=1cm, style={black,opacity=1}] {\small $f$};
    \draw [->,opacity=.3,thick] (\N,-1.45) -- (\N,-1.75);

    % Gf
    \foreach \i in {0,...,\N} { 
      \draw (\i,0) -- +(0,0) node[below=1.7cm] {\small $\mathbf{G}f$};
   }
\end{tikzpicture}
\end{document}

Answer 1

三个基本点：

1. 您可以在节点之间绘制路径，无需使用明确的坐标。
2. 您可以执行更多类似的花哨的 foreach 循环\foreach \i in {0,...,\Nmm,\N,\Nm}，而不需要单独执行\N和\Nm。
3. 如果您将节点放置below在某条路径之后，它将被放置在该路径的最后一点。但是，您希望将它们放置在方块的中心下方。一个相当快速的解决方法是使用midway这里。

这会使代码更加简洁。

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{arrows,shapes,svg.path}
\begin{document}
  \begin{tikzpicture}[x=2cm]
    \pgfmathsetmacro\N{int(5)};
    \pgfmathsetmacro\Nm{int(\N-1)}; 
    \pgfmathsetmacro\Nmm{int(\N-2)};

    % Draw the number line 
    \draw (0,0) -- (\Nmm,0);
    \draw [dotted] (\Nmm,0) -- (\Nm,0);
    \draw (\Nm,0) -- (\N,0);

    % Regular grid
    \foreach \i in {0,...,\Nmm,\N,\Nm} {
        \draw (\i,0.1) -- + (0,-0.2) node[below,font=\small] {$x_\i$};
   }

    % Distance h
    \draw [|-|] (0,.5) -- (1,.5) node[midway,fill=white] {$h$};

    % Staggered Grid 
    \foreach \i in {1,...,\Nmm} {
        \pgfmathsetmacro\j{int(2*\i-1)};
        \draw (\i-.5,0.1) -- +(0,-0.2) node[below,font=\small] {$x_\frac{\j}{2}$};
   }
    \draw (\N-.5,0.1) -- + (0,-0.2) node[below,font=\small]{$_{N-\frac{1}{2}}$};

    % Vector functions
    \foreach \i in {0,...,\N} { 
      \draw [red, fill=red,opacity=.3] (\i,0) circle (1mm) 
      node[above=1cm,style={black,opacity=100},font=\small] (v\i) {$\mathbf{v}$};
   }

    % Dv
    \foreach \i [evaluate=\i as \j using {int(\i-1)}] in {1,...,\Nmm} { 
        \draw (\i-.5,0)  node[above=1cm,font=\small]  (D\i)
        {$\mathbf{D}\mathbf{v}$};
        \draw[->] (D\i) -- (D\i -| v\i.west);
        \draw[->] (D\i) -- (D\i -| v\j.east);
    }
    \draw (\N-.5,0.0) -- + (0,-0.0) node[above=1cm,font=\small] {$\mathbf{D}\mathbf{v}$};
    \draw [->,opacity=.3,thick] (\N-.9,1.25) -- (\N-.7,1.25);
    \draw [->,opacity=.3,thick] (\N-.1,1.25) -- (\N-.3,1.25);
    % Gf moved uo
    \foreach \i in {0,...,\N} { 
      \draw (\i,0) node[below=1.7cm,font=\small] (Gf\i) {$\mathbf{G}f$};
     }

    % Scalar functions
    \foreach \i [evaluate=\i as \j using {int(\i-1)}] in {1,...,\Nmm,\N} { 
        \draw [blue,fill=blue,opacity=.2] (\i-.55,-.1) rectangle (\i-.45,.1)
        node[midway,below=0.9cm, style={black,opacity=1},font=\small] (f\i) {$f$};
        % added midway and gave the nodes names
         \draw [->,opacity=.3,thick] (f\i) -- (Gf\i);
         \ifnum\i>0
         \draw [->,opacity=.3,thick] (f\i) -- (Gf\j);
         \fi
    }
     \draw [blue,fill=blue,opacity=.2] (-.05,-.1) rectangle (.05,.1) 
    node[midway,below=0.9cm, style={black,opacity=1},font=\small] (f0) {$f$};
    \draw [->,opacity=.3,thick] (f0) -- (Gf0);
     \draw [blue,fill=blue,opacity=.2] (\N-.05,-.1) rectangle (\N+.05,.1) 
    node[midway,below=0.9cm, style={black,opacity=1},font=\small] (fN) {$f$};
    \draw [->,opacity=.3,thick] (fN) -- (Gf\N);
\end{tikzpicture}
\end{document}