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局部临时变量赋值

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局部临时变量赋值

我确信这个问题已经以多种不同的方式被问过很多次了，但到目前为止，我发现的所有方法都无法奏效。所以我们开始吧：

我正在使用以下代码（我曾经在这里的某个地方找到过）来全局切换 tikz 图片的渲染：

\newif\ifshowtikz
\showtikztrue
% \showtikzfalse % <---- comment/uncomment that line

\let\oldtikzpicture\tikzpicture \let\oldendtikzpicture\endtikzpicture

\renewenvironment{tikzpicture}{%
  \ifshowtikz\expandafter\oldtikzpicture
  \else
  \fi }{%
  \ifshowtikz\oldendtikzpicture%
  \else
  \fi }

现在，我还在某些我总是希望渲染 tikz 图片的地方使用 tikz 图片。对于这些地方，我使用以下宏：

\newcommand{\propbox}[1]{
    \tikz{\node[
    draw,shade,rounded corners=0.1cm, top color=teal!30,bottom color=teal!80,blur shadow={shadow blur steps=5}] (A) {#1};}
}

我想在那个propbox对全局值敏感的宏中添加一个条件showtikz，如下所示：

if not showtikz:
   temp = showtikz
   showtikz = True
   # probbox code
   showtikz = temp
else:
   # probbox code

类似这样。我该怎么做？

答案1

请注意，您必须分别处理\tikz命令和{tikzpicture}环境。要摆脱\tikz命令，您可以使用\let\tikz\@gobble重新定义命令\tikz以删除其参数。要摆脱{tikzpicture}环境，您可以让它等于verbatim包中的注释环境。

为了定义\propbox，我们恢复组内部的定义，放入的定义\propbox，然后结束该组，这样我们暂时恢复的定义就超出了范围。

以下是带有示例的完整代码：

\documentclass{article}
\usepackage{verbatim}
\usepackage{tikz}

\makeatletter
\newcommand{\propbox}[1]{
    \bgroup % start local group
    % ensure {tikzpicture} environment is not a comment
    \let\tikzpicture\save@tikzpicture
    \let\endtikzpicture\save@endtikzpicture
    % Rather than restoring the value of \tikz shorter to use \save@tikz directly
    \save@tikz{\node[
    draw,shade,rounded corners=0.1cm, top color=teal!30,bottom color=teal!80] (A) {#1};}
    \egroup % The definitions go out of scope here so if tikz is not being displayed,
    % {tikzpicture} goes back to being a comment
}

% Save copies of tikz commands
\let\save@tikzpicture\tikzpicture
\let\save@endtikzpicture\endtikzpicture
\let\save@tikz\tikz

% A no-op defintion of \tikz that correctly gobbles argument 
% whether delimited by braces or semicolon
\def\gobbletikz{
    \@ifnextchar\bgroup % Is the argument brace delimited?
        {\@gobble}     % If the next character is an open brace, \@gobble suffices
        {\gobbletikz@} % Otherwise, it's semicolon delimited
}
% gobble until the next semicolon
\def\gobbletikz@#1;{}

% set tikz commands to be no-ops
\def\hidetikzpictures{
    \let\tikzpicture\comment
    \let\endtikzpicture\endcomment
    \let\tikz\gobbletikz
}

% restore tikz commands
\def\showtikzpictures{
    \let\tikzpicture\save@tikzpicture
    \let\endtikzpicture\save@endtikzpicture
    \let\tikz\save@tikz
}
\makeatother

\begin{document}
\hidetikzpictures
\begin{tikzpicture}
\node [draw] (0,0){hidden};
\end{tikzpicture}
\propbox{shown even though hidetikzpictures}
\tikz{\node[draw] (0,0) {also hidden};}
\tikz \node[draw]{also also hidden};
\vskip 12pt

\showtikzpictures
\begin{tikzpicture}
\node [draw] (0,0){shown};
\end{tikzpicture}
\propbox{shown either way}
\tikz{\node[draw] (0,0) {also shown};}
\tikz \node[draw]{also also shown};
\end{document}

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