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tikzcd 线中的单波

tag-icon • tag-icon tikz-pgf tikz-arrows tikz-cd
tikzcd 线中的单波

我正在尝试为 tikzcd 中的箭头创建一种格式，该格式实际上是拉长的波浪号： 箭头示例

我使用选项 1 绘制了这个例子这个答案，但我必须手动计算蛇的正确段长度。

有没有办法自动计算这个？例如：

arrows={decorate, decoration={snake, segment length=DISTANCE/2, amplitude=0.5mm}}

如果没有的话，还有其他方法吗？

任何帮助将非常感激。

答案1

我有一个基于的部分解决方案这个答案。

我复制了他们的辅助宏的全部内容，以及样式定义的大部分前半部分。我唯一负责的代码是注释“绘制波浪”下方的代码：

\makeatletter

% This helper macro finds the start and endpoints of a line between the source and target nodes and stores them in \sourcecoordinate and \targetcoordinate.
% #1 -- source node
% #2 -- target node
\def\findedgesourcetarget#1#2{
\let\sourcecoordinate\pgfutil@empty
\ifx\tikzcd@startanchor\pgfutil@empty % Check that the source doesn't have a specified anchor
    \def\tempa{\pgfpointanchor{#1}{center}}% if so, start by taking the center of that coordinate
\else
    \edef\tempa{\noexpand\pgfpointanchor{#1}{\expandafter\@gobble\tikzcd@startanchor}} % If it has an anchor, use that
    \let\sourcecoordinate\tempa
\fi
\ifx\tikzcd@endanchor\pgfutil@empty % check that the target doesn't have a specified anchor
    \def\tempb{\pgfpointshapeborder{#2}{\tempa}}% if so, our end point is the point on the boundary of node b that is in the direction of our initial start coordinate
\else
    \edef\tempb{\noexpand\pgfpointanchor{#2}{\expandafter\@gobble\tikzcd@endanchor}}% If it has a specified anchor, use that
\fi
\let\targetcoordinate\tempb
\ifx\sourcecoordinate\pgfutil@empty%
    \def\sourcecoordinate{\pgfpointshapeborder{#1}{\tempb}}%
\fi
}

\tikzset{wave/.style = {
-,
to path={\pgfextra{
        \findedgesourcetarget{\tikzcd@ar@start}{\tikzcd@ar@target} % find endpoints
    % Rotate coordinate system so that line goes in x direction
    \ifx\tikzcd@startanchor\pgfutil@empty
        \def\tikzcd@startanchor{.center}
    \fi
    \ifx\tikzcd@endanchor\pgfutil@empty
        \def\tikzcd@endanchor{.center}
    \fi
    \pgfmathanglebetweenpoints{\pgfpointanchor{\tikzcd@ar@start}{\expandafter\@gobble\tikzcd@startanchor}}{\pgfpointanchor{\tikzcd@ar@target}{\expandafter\@gobble\tikzcd@endanchor}}
    \pgftransformrotate{\pgfmathresult}
    % Draw the wave
    \newdimen\xdiff
    \pgfextractx{\xdiff}{\pgfpointdiff{\sourcecoordinate}{\targetcoordinate}}
    \newdimen\ydiff
    \pgfextracty{\ydiff}{\pgfpointdiff{\sourcecoordinate}{\targetcoordinate}}
    \newdimen\finalDist
    \pgfmathparse{abs(veclen(\xdiff,\ydiff))*0.85}
    \pgfmathsetlength\finalDist{\pgfmathresult pt}

    \pgfmathsetlength\pgfdecorationsegmentlength{\finalDist}

    \pgfmathparse{0.038*\finalDist+0.6}
    \pgfmathsetlength\pgfdecorationsegmentamplitude{\pgfmathresult pt}

    \pgfsetarrows{->}

    \pgfpathmoveto{\sourcecoordinate}
    \pgfpathsnaketo{snake}{\targetcoordinate}

    \pgfusepath{stroke}
}}}}

\makeatother

使用辅助宏，我检索要连接的点并计算它们之间的距离。然后我使用它来定义蛇的幅度和段长度。

我在这些定义中使用的常数看起来是任意的，我是通过试验和改进找到它们的，但我会采用一种更严格的方法。

然后

\begin{center}
    Original method:
    \begin{tikzcd}[arrows={decorate, decoration={snake,segment length=7.3mm, amplitude=0.5mm}}]
        A \arrow[r,"",decorate=true] & B
    \end{tikzcd}
\end{center}
\hspace{2cm}
\begin{center}
    Custom style
    \begin{tikzcd}
        A \arrow[r, wave] & B & & \\
        A \arrow[rr, wave] & & B & \\
        A \arrow[rrr, wave] & & & B
    \end{tikzcd}
\end{center}

给出 结果比较

我目前的主要问题是箭头上方的标签不再起作用。我会尝试修复此问题，并尽可能更新此答案。

如果有人有更简单的方法可以避免此类问题，请告诉我！

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