如何缩短末端的箭头？

Question

我想沿着红点的方向绘制线圈线，但它们不应超出圆。是否可以将箭头的长度缩短为圆的半径？

我的代码：

    \begin{tikzpicture}[]
    %Left
    \node (m_1) at (-3.5,1) [middle] {};
    \node (c_1) at (-3.5,1) [circle,draw=black, style=dashed, inner sep=0pt,minimum size=4cm] {};
    
    \node (sim1_1) at (-1,2) [sim] {};
    \node (sim2_1) at (-4,4) [sim] {};
    \node (sim3_1) at (-6,-0.5) [sim] {};
    \node (sim4_1) at (-1.5,-1) [sim] {};
    \node (dissim1_1) at (-4,-0.5) [dissim] {};
    \node (dissim2_1) at (-3,-1.5) [dissim] {};
    \node (dissim3_1) at (-4.5,2) [dissim] {};
    \node (dissim4_1) at (-3,2) [dissim] {};
    \node (dissim5_1) at (-1,0.5) [dissim] {};
    
    
    \node (m_2) at (3.5,1) [middle] {};
    \node (c_2) at (3.5,1) [circle,draw=black, style=dashed, inner sep=0pt,minimum size=4cm] {};
    
    \node (sim1_2) at (6,2) [sim] {};
    \node (sim2_2) at (3,4) [sim] {};
    \node (sim3_2) at (1,-0.5) [sim] {};
    \node (sim4_2) at (5.5,-1) [sim] {};
    \node (dissim1_2) at (7-4,-0.5) [dissim] {};
    \node (dissim2_2) at (7-3,-1.5) [dissim] {};
    \node (dissim3_2) at (7-4.5,2) [dissim] {};
    \node (dissim4_2) at (7-3,2) [dissim] {};
    \node (dissim5_2) at (7-1,0.5) [dissim] {};
    
    
    \draw[spring1] (m_1) -- (sim1_1);
    \draw[spring1] (m_1) -- (sim2_1);
    \draw[spring1] (m_1) -- (sim3_1);
    \draw[spring1] (m_1) -- (sim4_1);
    
    \draw[spring2] (m_2) -- (dissim1_2);
    \draw[spring2] (m_2) -- (dissim2_2);
    \draw[spring2] (m_2) -- (dissim3_2);
    \draw[spring2] (m_2) -- (dissim4_2);
    \draw[spring2] (m_2) -- (dissim5_2);
 
    \end{tikzpicture} 

Answer 1

一种方法是使用intersectionsTi钾kZ 库并从圆心到从中心到圆外选定节点的路径交点绘制弹簧：

\documentclass[border=3mm]{standalone}%
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                decorations.pathmorphing,
                intersections}

 \begin{document}
    \begin{tikzpicture}[
            > = {Straight Barb[scale=0.8]},
   dot/.style = {circle, draw, fill=#1, inner sep=2pt,
                 node contents={}},
 dot/.default = green,
middle/.style = {dot=blue!50, inner sep=3pt, node contents={}},
   decoration = {coil, segment length=4pt, pre length=8pt, post length=8pt}
                        ]
%Left
\node (m) at (-3.5,1) [middle];
\node (c) at (-3.5,1) [circle, draw, dashed, inner sep=0pt, minimum size=4cm,
                         name path=C] {};

\node (sim1_1) at (-1,2)    [dot];
\node (sim2_1) at (-4,4)    [dot];
\node (sim3_1) at (-6,-0.5) [dot];
\node (sim4_1) at (-1.5,-1) [dot];
\node (dissim1_1) at (-4,-0.5)  [dot=red];
\node (dissim2_1) at (-4.5,2)   [dot=red];
\node (dissim3_1) at (-3,2)     [dot=red];
\node (dissim4_1) at (-3,-1.5)  [dot=red];
\node (dissim5_1) at (-1,0.5)   [dot=red];

    \foreach \i in {1,2,3} % nodes inside of circle
\draw[<->, decorate] (m) -- (dissim\i_1);

    \foreach \i [count=\j from 4] in {a,b} % nodes outside of circle
{
\path[name path=\i] (m) -- (dissim\j_1);
\draw[<->, decorate, name intersections={of=C and \i,by=s}] (m) -- (s);
}
    \end{tikzpicture}
\end{document}