☰

如何绘制虚线

tag-icon • tag-icon tikz-pgf pgfplots graphics tikz-path
如何绘制虚线 
\begin{tikzpicture}
  \begin{axis}[
      axis x line = middle,
      axis y line = center,
      axis line style = {-},
      xlabel = $$,
      ylabel = $$,
      xmin = -2*pi,
      xmax = 2*pi,
      clip=false,
      xtick = {-6.2832, -4.7124, -3.1416, -1.5708, 0, 1.5708, 3.1416, 4.7124, 6.2832},
      xticklabels = {${-2\pi}$, ${-\frac{3\pi}2}$, ${-\pi}$, ${-\frac{\pi}2}$, ${0}$, ${\frac\pi2}$, ${\ \ \pi}$, ${\frac{3\pi}2}$, ${2\pi}$},
      ymin = -1,
      ymax = 1,
      ytick={-1,0,1},
      yticklabels={,,},
      height = 10em,
      width = 28em,
    ]
    \addplot+[
      black,
      mark=none,
      const plot,
    ]
    coordinates {(-2*pi,1) (-pi,1) (-pi,-1) (0,-1) (0,1) (pi,1) (pi,-1) (2*pi,-1)};
    \path (axis cs:0,0)
      node [anchor=south west,yshift=-0.65em,xshift=-0.585em,font=\normalsize] {0};
  \end{axis}
\end{tikzpicture}

生成此方波：

在此处输入图片描述

但我想把垂直线变成点线或虚线，得到类似

在此处输入图片描述

（抱歉插图太差了）

我怎样才能做到这一点？

答案1

您可以对坐标进行分组，插入空行并使用empty lines = jump。然后绘制两个图，一个用于水平线，一个用于垂直线。添加dotted第二个图。

在此处输入图片描述

\documentclass[border=1mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\begin{document}
\begin{tikzpicture}
  \begin{axis}[
      axis x line = middle,
      axis y line = center,
      axis line style = {-},
      % no y axis
      %y axis line style = {draw=none},
      xlabel = $$,
      ylabel = $$,
      xmin = -2*pi,
      xmax = 2*pi,
      clip=false,
      xtick = {-6.2832, -4.7124, -3.1416, -1.5708, 0, 1.5708, 3.1416, 4.7124, 6.2832},
      xticklabels = {${-2\pi}$, ${-\frac{3\pi}2}$, ${-\pi}$, ${-\frac{\pi}2}$, ${0}$, ${\frac\pi2}$, ${\ \ \pi}$, ${\frac{3\pi}2}$, ${2\pi}$},
      ymin = -1,
      ymax = 1,
      ytick={-1,0,1},
      yticklabels={,,},
      height = 10em,
      width = 28em,
    ]
    % horizontal parts
    \addplot+[
      red,very thick,
      mark=none,
      const plot,
      empty line=jump,
    ]
    coordinates {
        (-2*pi,1)
        (-pi,1)

        (-pi,-1)
        (0,-1)

        (0,1)
        (pi,1)

        (pi,-1)
        (2*pi,-1)
    };
    % vertical parts
    \addplot+[
      red,very thick,dotted,
      mark=none,
      const plot,
      empty line=jump,
    ]
    coordinates {
        (-pi,1)
        (-pi,-1)

        (0,-1)
        (0,1)

        (pi,1)
        (pi,-1)
    };
    \path (axis cs:0,0)
      node [anchor=south west,yshift=-0.65em,xshift=-0.585em,font=\normalsize] {0};
  \end{axis}
\end{tikzpicture}
\end{document}

相关内容