TikZ：“之字形”线条

Question

如何轻松获取刚刚给出的代码中的以下红线？

是否可以只给出起点和终点位置，就能获得两种路径？

这个问题更多的是关于路径而不是数独。我给出数独的代码是为了测试一个解决方案在“现实生活”示例中是否有效。

第一种风格

第二种风格

代码

\documentclass{article}
    \usepackage{tikz}
    \usetikzlibrary{backgrounds}
    \usepackage{graphicx}

% Some customizable styles
    \tikzset {
        highlight/.style = {
            yellow,
            opacity = 0.3
        },
        digit/.style = {
            minimum height = 5mm,
            minimum width = 5mm,
            anchor = center
        },
        circle/.style = {
            draw = green!80!black,
            dotted,
            very thick
        },
        circle number/.style = {
            draw = #1,
            very thick
        },
        cross/.style = {
            red,
            opacity = .5,
            shorten >= 1mm,
            shorten <= 1mm,
            very thick,
            line cap = round
        },
        hint/.style = {
            blue,
            font = \sf,
            minimum width = 3mm,
            minimum height = 3mm
        }
    }

% Modified the \node to give a unique name to each one, which is the
% row number, a dash and the column number. E.g: 1-1, 4-5, etc.
    \newcounter{row}
    \newcounter{col}

    \newcommand\setrow[9]{
        \setcounter{col}{1}
        \foreach \n in {#1, #2, #3, #4, #5, #6, #7, #8, #9} {
            \edef\x{\value{col} - 0.5}
            \edef\y{9.5 - \value{row}}
            \node[digit,name={\arabic{row}-\arabic{col}}] at (\x, \y) {\n};
            \stepcounter{col}
        }
        \stepcounter{row}
    }

% New code -------------------------------------------------------------
    \def\highlightcell#1#2{
        \begin{scope}[on background layer]
            \fill[highlight] (#1-#2.north west) rectangle (#1-#2.south east);
        \end{scope}
    }

    \def\circlecell#1#2{
        \draw[circle] (#1-#2) circle(4mm);
    }

    \def\crosscell#1#2{
        \draw[cross] (#1-#2.north west) -- (#1-#2.south east);
        \draw[cross] (#1-#2.north east) -- (#1-#2.south west);
    }

    \def\highlightrow#1{
        \begin{scope}[on background layer]
            \fill[highlight] (#1-1.north west) rectangle (#1-9.south east);
        \end{scope}
    }

    \def\highlighcolumn#1{
        \begin{scope}[on background layer]
            \fill[highlight] (1-#1.north west) rectangle (9-#1.south east);
        \end{scope}
    }

    \def\highlightrectangle#1#2#3#4{
        \begin{scope}[on background layer]
            \fill[highlight] (#1-#2.north west) rectangle (#3-#4.south east);
        \end{scope}
    }

    \def\hintcell#1#2#3{
        \node at (#1-#2) {\hintbox{#3}};
    }


% Command to circle numbers:
% #1: optional -> circle color
% #2: mandatory -> cell identifier
% #3: mandatory -> name of the cell
    \newcommand\circlenumber[3][red!80!black]{
        \draw[circle number=#1, radius=5mm] (#2) circle node[outer sep=1mm] (#3){};
    }

% UGLY code. Do not read :-)
    \def\hintbox#1{
        \resizebox{4.5mm}{4.5mm}{%
            \tikz[scale=0.3]{%
                \def\auxc{0}
                \foreach \m in {1,...,9} {
                    \pgfmathparse{mod(\auxc,3)}
                    \xdef\x{\pgfmathresult}
                    \pgfmathparse{-floor(\auxc/3)}
                    \xdef\y{\pgfmathresult}
                    \xdef\hintprinted{0}
                    \foreach \n in {#1} {
                        \ifnum\n=\m
                            \node[hint] at (\x,\y) {\n};
                            \xdef\hintprinted{1}
                        \fi
                    }
                    \ifnum\hintprinted=0
                        \node[hint, opacity=0.1] at (\x,\y) {\m};
                    \fi
                    \pgfmathparse{\auxc+1}
                    \xdef\auxc{\pgfmathresult}
                }
            }%
        }
    }


\begin{document}

\begin{tikzpicture}[scale=.5]
    \begin{scope}
        \draw (0, 0) grid (9, 9);
        \draw[very thick, scale=3] (0, 0) grid (3, 3);

        \setcounter{row}{1}
        \setrow { }{2}{ }  {5}{ }{1}  { }{9}{ }
        \setrow {8}{ }{ }  {2}{ }{3}  { }{ }{6}
        \setrow { }{3}{ }  { }{6}{ }  { }{7}{ }

        \setrow { }{ }{1}  { }{ }{ }  {6}{ }{ }
        \setrow {5}{4}{ }  { }{ }{ }  { }{1}{9}
        \setrow { }{ }{2}  { }{ }{ }  {7}{ }{ }

        \setrow { }{9}{ }  { }{3}{ }  { }{8}{ }
        \setrow {2}{ }{ }  {8}{ }{4}  { }{ }{7}
        \setrow { }{1}{ }  {9}{ }{7}  { }{6}{ }
    \end{scope}
\end{tikzpicture}

\end{document}

Answer 1

我现在没有时间研究自动从起始和结束坐标中推导出适当的中间坐标的通用解决方案，但以下代码可以手动绘制您想要的箭头，并且可以作为解决一般情况的起点：

\draw[->,very thick, red, rounded corners] 
    (1-1.center) -- (1-9.center) 
 |- (2-1.center) 
 |- (3-9.center) 
 |- (4-1.center) 
 |- (5-3.center);

和：

\draw[->,very thick, red] 
     (1-1.center) -- (1-9.center) 
  -- (2-1.center) -- (2-9.center) 
  -- (3-1.center) -- (3-6.center);