tikzpicture 中的反射对象

Question

我正在尝试使用 tikzpicture 来绘制不同的圆锥曲线。

最后，我想反射我围绕 y 轴绘制的两条圆弧，得到一条双曲线，但我不知道该怎么做。反射的部分没有出现在我想要的位置。

这是我的代码：

\begin{tikzpicture}

\draw (0,0) ellipse (1cm and 0.3cm);

\draw (0,-3) -- (-1,0); 

\draw (0,-3) -- (1,0);

\draw (-1,-6) -- (0,-3);

\draw (1,-6) -- (0,-3);

\draw (0,-6) ellipse (1cm and 0.3 cm);

\draw (2,-3) circle (0.75cm);

\draw (4.5,-3) ellipse (1cm and 0.4 cm);

\draw (7,-3.5) parabola (6.5,-2) ;

\draw (7,-3.5) parabola (7.5,-2);

\draw (9, -2.5) arc (5:45:2);

\draw (9, -2.5) arc (5:-45:2);

\end{tikzpicture}

我明白了：

为了反映弧线，我使用以下代码：

\begin{scope}[yscale=1,xscale=-1]
\draw (9, -2.7) arc (5:45:1);
\draw (9, -2.7) arc (5:-45:1);
\end{scope}

但后来我得到了这个：

有人能帮我解决这个问题吗？任何帮助我都会感激不尽。提前谢谢大家！

Answer 1

弧线之所以移动这么远，是因为水平坐标9被映射到了-9。反射事物的一个方便方法是将它们绘制在图片中，该图片可以反射（或以其他方式变换）。我不知道这两个弧之间的关系，但您可以调整水平坐标（现在是 ）-0.5来获得您想要的结果。（或者您给我一个提示。）

\documentclass[tikz,border=3.14mm]{standalone}
\begin{document}
\begin{tikzpicture}[pics/my arc/.style={code={
\draw (-0.5, -2.5) arc (5:45:2);
\draw (-0.5, -2.5) arc (5:-45:2);}}]

\draw (0,0) ellipse (1cm and 0.3cm);

\draw (0,-3) -- (-1,0); 

\draw (0,-3) -- (1,0);

\draw (-1,-6) -- (0,-3);

\draw (1,-6) -- (0,-3);

\draw (0,-6) ellipse (1cm and 0.3 cm);

\draw (2,-3) circle (0.75cm);

\draw (4.5,-3) ellipse (1cm and 0.4 cm);

\draw (7,-3.5) parabola (6.5,-2) ;

\draw (7,-3.5) parabola (7.5,-2);

\path (9,0) pic {my arc} pic[xscale=-1] {my arc};

\end{tikzpicture}
\end{document}

或者，您可以引入一种反映移位的 x 轴或 y 轴的样式。

\documentclass[tikz,border=3.14mm]{standalone}
\begin{document}
\begin{tikzpicture}[reflect at x/.style={xshift=#1*1cm,xscale=-1,xshift=-1*#1*1cm},
reflect at y/.style={yshift=#1*1cm,yscale=-1,yshift=-1*#1*1cm}]
 \draw (0,0) ellipse (1cm and 0.3cm);
 \draw (0,-3) -- (-1,0); 
 \draw (0,-3) -- (1,0);
 \draw (-1,-6) -- (0,-3);
 \draw (1,-6) -- (0,-3);
 \draw (0,-6) ellipse (1cm and 0.3 cm);
 \draw (2,-3) circle (0.75cm);
 \draw (4.5,-3) ellipse (1cm and 0.4 cm);
 \draw (7,-3.5) parabola (6.5,-2) ;
 \draw (7,-3.5) parabola (7.5,-2);
 \draw (9, -2.5) arc (5:45:2);
 \draw (9, -2.5) arc (5:-45:2);
 \begin{scope}[reflect at x=9.5]
  \draw (9, -2.5) arc (5:45:2);
  \draw (9, -2.5) arc (5:-45:2);
 \end{scope}
\end{tikzpicture}
\end{document}