整合之路上的箭头

Question

我需要在半径为 1 的粗圆上画一个逆时针箭头（通过使用 {Latex[length=x cm]}）。

\begin{tikzpicture}
\draw[thick,->] (0,-2) -- (0,2.5);
\draw[thick,->] (-2,0) -- (2.5,0);
\draw[thick,dashed] (0.5,0.5) circle (0.5cm);
\draw[ultra thick](0.5,0.5) circle (1cm);
\draw[thick,dashed] (0.5,0.5) circle (1.5cm);
\draw[fill] (0.5,0.5) circle (0.05);
\draw[decorate,decoration={brace, mirror}, black] (0.5,0.5) -- (45:0.2)
node[midway,above,sloped] {$R_{1}$};
\draw[decorate,decoration={brace, mirror}, black] (0.5,0.5) -- (135:1.3)
node[midway,sloped,above]{$R_{2}$};
\end{tikzpicture}

Answer 1

我会弯曲箭头并对括号使用一些更直观的坐标规范。

\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{arrows.meta}% Arrows library for...
\usetikzlibrary{bending}% The bending library is the one that allows the bending of the arrows
\usetikzlibrary{decorations.pathreplacing} % braces
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[scale=2]
\draw[thick,->] (0,-2) -- (0,2.5);
\draw[thick,->] (-2,0) -- (2.5,0);
\draw[thick,dashed] (0.5,0.5) circle (0.5cm);
\draw[ultra thick](0.5,0.5) circle (1cm);
\draw[thick,dashed] (0.5,0.5) circle (1.5cm);
\draw[fill] (0.5,0.5) circle (0.05);
\draw[gray,ultra thick,decorate,decoration={brace}] (0.5,0.5) -- ++(0:0.5)
node[midway,above,sloped] {$R_{1}$};
\draw[gray,ultra thick,decorate,decoration={brace, mirror}] (0.5,0.5) -- ++(150:1.5)
node[midway,sloped,above]{$R_{2}$};
\draw[ultra thick,{Latex[length=0.3cm,bend]}-] ($(90:1)+(0.5,0.5)$) arc(90:45:1);
\end{tikzpicture}
\end{document}

Answer 2

\documentclass[12pt,a4paper]{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing,decorations.markings}
\begin{document}

\begin{tikzpicture}
\draw[thick,->] (0,-2) -- (0,2.5);
\draw[thick,->] (-2,0) -- (2.5,0);
\draw[thick,dashed] (0.5,0.5) circle (0.5cm);
\draw[ultra thick,postaction={decorate,
   decoration={markings,mark=at position .1 with {\arrow{>};}}}](0.5,0.5) circle (1cm);
\draw[thick,dashed] (0.5,0.5) circle (1.5cm);
\draw[fill] (0.5,0.5) circle (0.05);
\draw[decorate,decoration={brace, mirror}, black] (0.5,0.5) -- (45:0.2)
node[midway,above,sloped] {$R_{1}$};
\draw[decorate,decoration={brace, mirror}, black] (0.5,0.5) -- (135:1.3)
node[midway,sloped,above]{$R_{2}$};
\end{tikzpicture}

\end{document}

Answer 3

为了好玩，因为阿博阿马尔和土拨鼠同时制作了最少的工作示例......我绘制了稍微奇特的图像示例：

\documentclass[12pt,tikz, margin=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                decorations.pathreplacing,
                calligraphy,
                decorations.markings}

\begin{document}
    \begin{tikzpicture}[
        > = Straight Barb,
BC/.style = {
        decorate,
        decoration={calligraphic brace, amplitude=4pt,
        pre =moveto, pre  length=1pt,
        post=moveto, post length=1pt,
        raise=1pt,
        #1},% for mirroring of brace
        thick,
        pen colour={red}
        },
BC/.default={},
    decoration = {markings,mark=at position .1 with {\arrow{>};}},
R/.style = {font=\small, text=red, midway, above=#1}
                            ]
\draw[->]   ( 0,-1.7) edge (0,2.8)
            (-1.7, 0)  to  (2.8,0);
\draw[thick,dashed] (0.5,0.5) circle (7mm);
\draw[ultra thick,postaction={decorate}]
                    (0.5,0.5) circle (14mm);
\draw[thick,dashed] (0.5,0.5) circle (21mm);
\fill (0.5,0.5) circle (0.5mm);
\draw[BC] (0.5,0.5) -- +(  7mm,0) node[R=3pt] {$R_{1}$};
\draw[BC=mirror] (0.5,0.5) -- +(-21mm,0) node[R=3pt]{$R_{2}$};
    \end{tikzpicture}
\end{document}