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如何在线段上放置括号？

tag-icon • tag-icon tikz-pgf
如何在线段上放置括号？

所以我这里有这段代码，

   \begin{tikzpicture}

    % Draw the axes
    \draw [->,black] (-1.5,0) -- (3,0) ;
    \draw [->,black] (0,-1.5) -- (0,3) ;

    % Draw the line
    \draw[-,black](0,0)--(3,2);

    % Draw the circle
    \path [draw,green] (+1.5,0) circle (1.5);
    \path [draw,cyan] (0,1.5) circle (1.5);

    % Intersection of circle and line
    \draw[dashed,cyan](0,0.93)--(1.38,0.93);
    \draw[dashed,cyan](1.38,0.93)--(1.38,0);
    \draw[dashed,green](0,1.38)--(2.1,1.38);
    \draw[dashed,green](2.1,0)--(2.1,1.38);
  %  \node[] at (-0.25,1.78){$y$};

     \node[] at (-0.25,0.93){$y_3$};
     \node[] at (1.38,-0.25){$x_3$};


\coordinate (a) at (0,0);
      \coordinate (b) at (1.38,0.93);
    \draw[decorate,decoration={brace,amplitude=5pt,raise=1pt,mirror},yshift=0pt] (a) -- (b) node [midway,yshift=-10pt, xshift = 10pt]{$|z_3|$};
     \node[] at (-0.25,1.38){$y_2$};
     \node[] at (2.1,-0.25){$x_2$};  

   % \node[] at (2.9,-0.25) {$x$};

    % Draw the angle
    \draw [red] (0,0.3) arc (90:33:0.3);
    \draw[red] (0,0.4)arc(90:33:0.4);
    \node[] at (60:.6)  {$\alpha$};

    % Done
\end{tikzpicture}

，得到以下图像：

在此处输入图片描述

但是，我想做的是在图片所示的部分上制作支架/标记。（我手绘的位置很清楚）。

我该如何修改上述内容才能做到这一点？

答案1

对于括号，您可以使用装饰brace。您可以使用intersections库来计算线和圆之间的交点；这样，您就不必手动计算坐标；我还将字体大小缩小为\scriptsize：

\documentclass{article}
\usepackage{tikz}% just for the example
\usetikzlibrary{decorations.pathreplacing,intersections}
\begin{document}

 \begin{tikzpicture}[every node/.append style={font=\scriptsize}]

    % Draw the axes
    \draw [->,black] (-1.5,0) -- (3,0) ;
    \draw [->,black] (0,-1.5) -- (0,3) ;

    % Draw the line
    \path[name path=line,draw,-] (0,0) -- (3,2);

    % Draw the circle
    \path [name path=greencircle,draw,green] (+1.5,0) circle (1.5);
    \path [name path=bluecircle,draw,cyan] (0,1.5) circle (1.5);

% find intersections of line and circles
\path[name intersections={of=line and bluecircle, by={a,b}}];
\path[name intersections={of=line and greencircle, by={c,d}}];

% lines from axes to intersection points
    \draw[dashed,cyan] (0,0|-b) -- (b);
    \draw[dashed,cyan] (b|-0,0) -- (b);
    \draw[dashed,green] (0,0|-c) -- (c);
    \draw[dashed,green] (c|-0,0) -- (c);;
  %  \node[] at (-0.25,1.78){$y$};

     \node[left] at (0,0|-b) {$y_3$};
     \node[below] at (b|-0,0) {$x_3$};

     \node[left] at (0,0|-c) {$y_2$};
     \node[below] at (c|-0,0) {$x_2$};  

   \coordinate (O) at (0,0);
% draw braces
    \draw[decorate,decoration={brace,amplitude=5pt,raise=0.5pt,mirror},yshift=0pt] (O) -- (b) node [midway,yshift=-9pt, xshift =6pt]{$|z_3|$};
    \draw[decorate,decoration={brace,amplitude=5pt,raise=0.5pt},yshift=0pt] (O) -- (c) node [midway,yshift=11pt, xshift =-5pt]{$|z_2|$};

   % \node[] at (2.9,-0.25) {$x$};

    % Draw the angle
    \draw [red] (0,0.3) arc (90:33:0.3);
    \draw[red] (0,0.4)arc(90:33:0.4);
    \node[] at (60:.6)  {$\alpha$};

    % Done
\end{tikzpicture}
\end{document}

在此处输入图片描述

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