![在 TikZ 中结合不同函数与不同域的图](https://linux22.com/image/368704/%E5%9C%A8%20TikZ%20%E4%B8%AD%E7%BB%93%E5%90%88%E4%B8%8D%E5%90%8C%E5%87%BD%E6%95%B0%E4%B8%8E%E4%B8%8D%E5%90%8C%E5%9F%9F%E7%9A%84%E5%9B%BE.png)
我想将通过某些算法生成的不同图组合到一些长路径(可用于剪辑)。我对 等魔法缺乏理解\noexpand
。\expandafter
这是我的 MWE:
\documentclass{article}
\usepackage{tikz}
\newcommand{\myparabola}[2]{
\pgfmathsetmacro{\myxmin}{min(2*sin(#1),-1)}
\pgfmathsetmacro{\myxmax}{max(2*sin(#1),1)}
plot[domain=\myxmin:\myxmax,variable=#2] ({#2},{#2*#2})
}
\begin{document}
This, of course, works:
\begin{center}
\begin{tikzpicture}
\pgfmathsetmacro{\myxmin}{min(2*sin(100),-1)}
\pgfmathsetmacro{\myxmax}{max(2*sin(100),1)}
\draw plot[domain=\myxmin:\myxmax,variable=\x] ({\x},{\x*\x});
\draw[clip] plot[domain=0:180,variable=\x] ({\x/100},{sin(\x)})
plot[domain=0:180,variable=\x] ({\x/100},{-sin(\x)});
\fill[red] circle (1.1);
\end{tikzpicture}
\end{center}
I want the result here be the same as above:
\begin{center}
\begin{tikzpicture}
% \draw \myparabola{100}{\x} ; % DOES NOT WORK
\end{tikzpicture}
\end{center}
Ultimately I'd like to plot several of those and/or use them in some clippings:
\begin{center}
\begin{tikzpicture} %DOES NOT WORK
% \clip \myparabola{100}{\x} \myparabola{200}{\x} \myparabola{-100}{\x};
\end{tikzpicture}
\end{center}
And of course I'm not really interested in parabolae, but more general functions
which I construct with an analogue of \verb|\myparabola|.
\end{document}
是否可以定义\myparabola
命令并以某种方式使用它,以便我可以将其插入到某些\draw
命令中\clip
?
附录:我取得了一点点进展,现在被一个更基本的问题困住了。看看这个 MWE:
\documentclass{article}
\usepackage{tikz}
\newcommand{\myparabola}[1]{%
%\pgfmathsetmacro{\myxmin}{1}% IF I UNCOMMENT THIS LINES, THERE IS AN ERROR
plot[domain=-1:1] ({\noexpand\x},{#1*\noexpand\x*\noexpand\x})
}
\begin{document}
\begin{tikzpicture}
\draw[variable=\x] \myparabola{1} \myparabola{-1};
\end{tikzpicture}
\end{document}
它产生了预期的结果。但是,如果我敢取消注释该行\pgfmathsetmacro{\myxmin}{1}
,就会出现错误! Package tikz Error: Giving up on this path. Did you forget a semicolon?.
。这是为什么?任何部分答案都将不胜感激。
答案1
问题是你\pgfmathsetmacro
在路径中使用。如果你使用,这是可以做到的\pgfextra{\pgfmathsetmacro...}
,但我应该指出手册中对此的说法(第 14.20 节PGF-extra 操作):
在某些情况下,您可能需要在构建路径时“进行一些计算或其他操作”。为此,您可能希望暂停路径的构建并暂停 Ti钾Z 解析路径后,您可能希望执行一些 TeX 代码,然后恢复路径解析。可以使用以下路径操作实现此效果
\pgfextra
。请注意,此操作仅应由真正的专家使用,并且仅应在巧妙的宏内部深处使用,而不能在正常路径上使用。
我并不认为自己是真正的专家,而且我不知道这方面是否有任何注意事项。
\documentclass{article}
\usepackage{tikz}
\newcommand{\myparabola}[2]{
\pgfextra{% <- put path construction on hold, and do the following:
\pgfmathsetmacro{\myxmin}{min(2*sin(#1),-1)}
\pgfmathsetmacro{\myxmax}{max(2*sin(#1),1)}
}
plot[domain=\myxmin:\myxmax,variable=#2] ({#2},{#2*#2})
}
\begin{document}
This, of course, works:
\begin{center}
\begin{tikzpicture}
\pgfmathsetmacro{\myxmin}{min(2*sin(100),-1)}
\pgfmathsetmacro{\myxmax}{max(2*sin(100),1)}
\draw plot[domain=\myxmin:\myxmax,variable=\x] ({\x},{\x*\x});
\draw[clip] plot[domain=0:180,variable=\x] ({\x/100},{sin(\x)})
plot[domain=0:180,variable=\x] ({\x/100},{-sin(\x)});
\fill[red] circle (1.1);
\end{tikzpicture}
\end{center}
I want the result here be the same as above:
\begin{center}
\begin{tikzpicture}
\draw \myparabola{100}{\x} ; % DOES NOT WORK
\end{tikzpicture}
\end{center}
Ultimately I'd like to plot several of those and/or use them in some clippings:
\begin{center}
\begin{tikzpicture}
\clip \myparabola{100}{\x} \myparabola{200}{\x} \myparabola{-100}{\x};
\end{tikzpicture}
\end{center}
And of course I'm not really interested in parabolae, but more general functions
which I construct with an analogue of \verb|\myparabola|.
\end{document}