绘制没有定义点的角度符号的问题

Question

我想用 TikZ 绘制这张图片：

我写了这段代码：

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{calc}
\usetikzlibrary{arrows.meta}

\pagestyle{empty}

\begin{document}

\begin{tikzpicture}[line cap=round]

 % First, define nodes
\node[circle, inner sep=0pt, label={[inner sep=0pt]above:{}}] (O) at (0, 0) {};
\node (O01) at (-4.5, 0) {};
\node (O11) at (-4.5, 1.1) {};
\node (O12) at (0, 1.1) {};
\node (O21) at (-4.5, -1.1) {};
\node (O22) at (0, -1.1) {};

 % Draw curved path
\draw [inner sep=0pt, line width=2pt, {Stealth[length=4mm]}-{Stealth[length=4mm]}] (O01) -- ($(O01)!2!(O)$);
\draw [inner sep=0pt, line width=2pt, {Stealth[length=4mm]}-{Stealth[length=4mm]}] (O11) -- ($(O11)!2!(O12)$);
\draw [inner sep=0pt, line width=2pt, {Stealth[length=4mm]}-{Stealth[length=4mm]}] (O21) -- ($(O21)!2!(O22)$);
\draw [inner sep=0pt, line width=2pt, -{Stealth[length=4mm]}] (O) -- (30:4.5cm);
\draw [inner sep=0pt, line width=2pt, -{Stealth[length=4mm]}] (O) -- (-50:5cm);
      
\end{tikzpicture}

\end{document}

我尝试过了

1. 在附近画出角度标志和文字，
2. 直线上的双箭头，但是我不能。

Answer 1

1. 使用坐标而不是节点来命名图表中的点。节点对于需要文本且具有边框的事物更有用。
2. 您可以使用tips钥匙仅绘制箭头尖而不绘制路径。
3. 找到水平线和“射线”之间的交点：
4. 这angles图书馆对于绘制角度标记非常有帮助。

我使用了一些颜色来区分图表的不同部分。您可以随意在选项中删除颜色。

代码

\documentclass[tikz]{standalone}
\usepackage{tikz}
\usetikzlibrary{angles, arrows.meta}
\begin{document}
\begin{tikzpicture}[
  thick,
  >        = { Straight Barb [angle' = 60] },
  >>/.tip  = { > [sep=+0pt +-2] > },
  angle eccentricity = 1.6
]
% define coordinates where horizontal lines start and end
% draw lines and also add extra arrow tips
\foreach[count=\y from -1] \yy in {bottom, center, top}{
  \draw[<->] (0, \y) coordinate (line left \yy)
         -- +(7,  0) coordinate (line right \yy); % +(…) denotes relative coordinates
  \path[->>, tips] (line left \yy) -- +(right:1.25);
}

% define rays and draw them
% find intersection between rays and horizontal lines
\path[->, blue] (2.25, 0) coordinate (ray start)
       edge coordinate[at end] (ray down) +(-50:3)
       edge coordinate[at end] (ray up)   +( 30:4)
   (intersection of ray start--ray up   and line left    top--line right    top)
     coordinate (rayline top)
   (intersection of ray start--ray down and line left bottom--line right bottom)
     coordinate (rayline bottom);

% draw angles by defining corner and specifying angle label
% uses angles library
\foreach \Corner/\Label in {
  line right    top--rayline top--ray up/\mu_0,
  line right center--ray   start--ray up/\alpha,
  ray down--ray      start--line right center/\gamma,
  ray down--rayline bottom--line right bottom/\omega_0
} \pic[draw, green!50!black, pic text=$\Label$] {angle/.expand once=\Corner};
\end{tikzpicture}
\end{document}

输出

Answer 2

类似的想法，不同的实现：做出您的选择。

• 先 <-> 行，然后 ->> 行（反之亦然），使用相对坐标
• 如果需要插入文本，请使用角度库和引号
• 到处使用极坐标，比如\draw[<-] (30:4) ...
• 记住这些坐标以便日后需要时使用\draw[<-] (30:4) coordinate (A) ...
• 调整或扩展您的风格[ ... ]

\documentclass[10pt,border=3mm,tikz]{standalone}

\usepackage{tikz}
\usetikzlibrary{calc}
\usetikzlibrary{arrows.meta,angles,quotes}

%\pagestyle{empty}

\begin{document}

 \begin{tikzpicture}[
        > = {Stealth},
    ]
    % ~~~ drawing <-> lines ~~~~~~~~~~~~~~~
    \draw [<->] (-4.5, 1.1) coordinate (11) -- (4.5, 1.1);
    \draw [<->] (-4.5, 0  ) coordinate (01) -- (4.5, 0  );
    \draw [<->] (-4.5,-1.1) coordinate (21) -- (4.5,-1.1);
    
    % ~~~ drawing <->> lines ~~~~~~~~~~~~~~~
    \draw [->>] (11) -- +(2,0);
    \draw [->>] (01) -- +(2,0);
    \draw [->>] (21) -- +(2,0);
    
    % ~~~ angles ~~~~~~~~~~~~~~~~~
    \draw[<-] (30:4) coordinate (A) -- (0,0) coordinate (zero) 
        -- (0:.01) coordinate (C)
        pic[draw, <->, angle radius=16mm,"$\alpha$"] 
            {angle = C--zero--A};
            
    \draw[<-] (-40:4) coordinate (A2) -- (0,0) coordinate (zero) 
        -- (0:.01) coordinate (C)
        pic[draw, <->, angle radius=16mm,"$-40^\circ$",red] 
            {angle = A2--zero--C};
 \end{tikzpicture}


\begin{tikzpicture}[line cap=round]

 % First, define nodes
\node[circle, inner sep=0pt, label={[inner sep=0pt]above:{}}] (O) at (0, 0) {};
\node (O01) at (-4.5,    0) {01};
\node (O11) at (-4.5,  1.1) {11};
\node (O12) at (   0,  1.1) {12};
\node (O21) at (-4.5, -1.1) {21};
\node (O22) at (   0, -1.1) {22};

 % Draw curved path
\draw [inner sep=0pt, line width=2pt, 
      {Stealth[length=4mm]}-{Stealth[length=4mm]}] 
      (O01) -- ($(O01)!2!(O)$);
      
\draw [inner sep=0pt, line width=2pt, {Stealth[length=4mm]}-{Stealth[length=4mm]}] (O11) -- ($(O11)!2!(O12)$);
\draw [inner sep=0pt, line width=2pt, {Stealth[length=4mm]}-{Stealth[length=4mm]}] (O21) -- ($(O21)!2!(O22)$);
\draw [inner sep=0pt, line width=2pt, -{Stealth[length=4mm]}] (O) -- (30:4.5cm);
\draw [inner sep=0pt, line width=2pt, -{Stealth[length=4mm]}] (O) -- (-50:5cm);
      
\end{tikzpicture}

\end{document}