错误使用 -| 或 |- 加上修饰的路径（例如蛇）

Question

-|如果我使用（水平优先然后垂直）或|-（垂直优先然后水平）命令绘制路径并使用snake-morphing 操作修饰路径，则路径的后半部分会放错位置。

以下是一个例子：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}

\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}
\path[draw=red,  ->]                              (0,0) -| (5,5);
\path[draw=black,->,decorate,decoration={snake}]  (0,0) -| (5,5);
\end{tikzpicture}
\caption{Wrong}
\end{figure}
\begin{figure}
\centering
\begin{tikzpicture}
\path[draw=red,  ->]                              (0,0) -| (5,5);
\path[draw=blue,->,decorate,decoration={snake}]   (5,0) -- (5,5);
\end{tikzpicture}
\caption{Correct}
\end{figure}
\end{document}

在这个特殊情况下，（黑色）垂直部分的偏移量与蛇形曲线的幅度相同，即黑色正弦曲线不以红色垂直路径为中心。第二张图显示了正弦曲线的实际预期外观（参见蓝色曲线）。

位移量随坐标的实际值而变化，并且与箭头结合时看起来非常丑陋，因为箭头仍然位于正确的位置中心。

我该如何解决？

Answer 1

这是解决该问题的一种方法。它基于托比亚斯 封闭 之字形，其中闭合和锯齿都不重要。然而，重要的是局部极值在切线空间中发生了偏移，参见这张照片。 结果：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}

\begin{document}


\pgfdeclaredecoration{centered zigzag}{initial}{
\state{initial}[
        width=+0pt,
        next state=big down,
        persistent precomputation={
            \pgfmathsetmacro{\myint}{int(\pgfdecoratedinputsegmentlength/\pgfdecorationsegmentlength)}
            \ifodd\myint
             \pgfmathsetmacro\matchinglength{
             \pgfdecoratedinputsegmentlength / int(1+\pgfdecoratedinputsegmentlength/\pgfdecorationsegmentlength)}
            \else
             \pgfmathsetmacro\matchinglength{
             \pgfdecoratedinputsegmentlength / int(\pgfdecoratedinputsegmentlength/\pgfdecorationsegmentlength)}
            \fi
            \setlength{\pgfdecorationsegmentlength}{\matchinglength pt}
            \pgfmathsetmacro{\myint}{int(\pgfdecoratedinputsegmentlength/\pgfdecorationsegmentlength)}
        }] {
        \pgfcoordinate{zigzag-cycle-start}{\pgfqpoint{0pt}{-\pgfdecorationsegmentamplitude}}
        \pgfpathmoveto{\pgfqpoint{0pt}{0pt}}
        }
  \state{big down}[switch if less than=+.5\pgfdecorationsegmentlength to center finish,
                   width=+.5\pgfdecorationsegmentlength,
                   next state=big up]
  {
    \pgfpathlineto{\pgfqpoint{0pt}{-\pgfdecorationsegmentamplitude}}
  }
  \state{big up}[switch if less than=+.5\pgfdecorationsegmentlength to center finish,
                 width=+.5\pgfdecorationsegmentlength,
                 next state=big down]
  {
    \pgfpathlineto{\pgfqpoint{0pt}{\pgfdecorationsegmentamplitude}}
  }
  \state{center finish}[width=0pt, next state=final]{
   % this state is unecessary at the moment
  }
  \state{final}
  {
  }
}
\begin{figure}
\centering
\begin{tikzpicture}
\path[draw=red,  ->]                              (0,0) -| (5,5);
\path[draw=blue,->,decorate,rounded corners,decoration={
            centered zigzag,
            segment length=10pt,
            amplitude=2mm
        }] (0,0) -| (5,5);
\end{tikzpicture}
\caption{Centered zigzag with rounded corners.}
\end{figure}
\end{document}