绘制不连续映射

Question

我想用 TIKZ 绘制类似的映射。我找不到如何绘制带有 $\alpha$ 和 $\bar t - \epsilon$ 和 $\bar t$ 的坐标系。

Answer 1

这是一种非常手动的方式，通过手动放置所有东西来完成。

\documentclass[tikz, border=20]{standalone}
\colorlet{myGreen}{green!50!black}
\begin{document}
    \begin{tikzpicture}
        \draw[<->,>=latex] (0, 4.2) -- (0, 0) -- (4.2, 0);
        \draw[ultra thick, myGreen] (0, 0) -- (1.8, 0);
        \draw[ultra thick, myGreen] (2.2, 0) -- (4, 0);
        \draw[ultra thick, myGreen] (1.8, 3.5) -- (2.2, 3.5);
        \draw[dashed, myGreen] (1.8, 0) -- (1.8, 3.5);
        \draw[dashed, myGreen] (2.2, 0) -- (2.2, 3.5);
        \draw[ultra thick, dashed, orange] (0, 0) -- (4, 0);
        \node[right, myGreen] at (2.2, 3.5) {\(u_2(t)\)};
        \node[above, orange] at (3.8, 0) {\(u_2^*(t)\)};
        \draw (-0.2, 3.5) -- (0.2, 3.5);
        \node[right] at (0.2, 3.5) {\(\alpha\)};
        \node[below left] at (2, 0) {\(\bar{t} - \varepsilon\)};
        \node[below] at (2.2, 0) {\(\bar{t}\)};
    \end{tikzpicture}
\end{document}