创建矢量图像

Question

我想知道是否有任何工具、程序或在线页面允许此类矢量图形：

这是 K. Jänich 所著的德文书《Funktionentheorie》。

Answer 1

那么，TikZ 就是这样一个工具。

代码

\documentclass[tikz]{standalone}
\usepackage{amssymb}
\usetikzlibrary{
  arrows.meta, % for nice arrow tips
  patterns,    % for north east lines
  quotes,      % for "…" syntax
}
\tikzset{% placing an arrow along a path
  pics/arrow/.default=>,
  pics/arrow/.style={
    /tikz/sloped, /tikz/allow upside down, code=\pgfarrowdraw{#1}}}
\begin{document}
\begin{tikzpicture}[
  thick, x=.5cm, y=.5cm, arrows={[round]},
  % OnLineTip uses specific sep to recenter itself
  OnLineTip/.tip={Straight Barb[scale=.6, angle=60:2pt 3, sep=-.75pt -2]},
  >={Straight Barb[scale=.6, angle=60:2pt 3]},
  outer sep=.2em, % only for this
  dot/.style={fill=black, circle, inner sep=+.75pt, node contents=},
]
\matrix[column sep=.5em]{
  \draw[pattern=north east lines, >=OnLineTip]
    (-1.5,-1) node[dot]
              -| pic[near start]{arrow}
                 pic[near end]  {arrow}
                 node[near start, below] {$Q$} (1.5,1)
              -| pic[near start]{arrow}
                 pic[near end]  {arrow}
                 node[near start, above] {$\gamma$} cycle;
&
\draw[->] (0,0) to["$\phi$", "$C^1$"'] (1,0);
&
\draw [rotate=30] ellipse[x radius=2, y radius=1.5];
\draw [pattern=north east lines, >=OnLineTip]
  (-1.3,-.7) node[dot]
             -- pic{arrow} (1.3, 0)
             -- pic{arrow} (.8, 1.2)
             -- pic{arrow} (-1.4, -.1)
             -- pic{arrow} cycle;
\draw[thin] (.8,-1) -- ++ (-30:.7)
   node[outer sep=auto, below right]{$U$};
&
\draw[->] (0,0) to["$f$"] (1,0);
&
\node {$\mathbb C$};
\\};
\end{tikzpicture}
\end{document}

输出