我已经制作了这个 pgfplot，但无法删除 yaxis 负部分。我希望 yaxis 从 0 开始。
附上完整的运行代码和图片。请在这方面给予指导。
\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepackage{amsmath}
\definecolor{babyblueeyes}{rgb}{0.63, 0.79, 0.95}
\definecolor{blizzardblue}{rgb}{0.67, 0.9, 0.93}
\begin{document}
\begin{center}
\begin{tikzpicture}[
declare function={
unifpdf(\x,\a,\b) = 1/(\b-\a);
}]
\begin{axis}[scale=2,
width=7cm, height=6cm,
axis x line = bottom,
axis x line shift=-0.008,
axis y line = left,
samples=10,
xmin=0,
xmax=35,
no marks,
scaled ticks=false,
tick label style={/pgf/number format/fixed},
xlabel=$x$,
xtick = {12,30},
xticklabels = {$5$,$20$},
xlabel style={xshift=18pt, yshift=34pt, at={(1,0)}, anchor=east},
ylabel style={rotate=-90, at={(0,1)}, anchor=south},
ymin=-0.008,
ymax=0.05,
ytick ={0,1/30},
yticklabels={$0$,$\dfrac{1}{20}$},
ylabel=$f_X(x)$]
\addplot[ultra thick, smooth, domain=0:30, color=babyblueeyes]
{unifpdf(x,0,30)};
\addplot[ultra thick, ycomb, mark=o, samples at={12,30}, dashed, color=blue]{unifpdf(x,0,30)};
\addplot[draw=none, smooth, thick, domain=0:12, fill=babyblueeyes, samples=30]{unifpdf(x,0,30)} \closedcycle;
\node at (axis cs:6,0.017) {$A$};
\draw [latex-latex](axis cs:3,0.0065) -- node [fill=babyblueeyes] {$W$} (axis cs:12,0.0065);
\draw [ultra thick,blue,dashed] (3,0) -- (3,0.0099);
\filldraw (3,0) circle (0.08cm);
% \draw[very thick, {Stealth}-{Stealth}] (3,0.0065) -- (12,0.0065);
\addplot[draw=none, smooth, thick, domain=12.05:30.05, fill=blizzardblue, samples=30]{unifpdf(x,0,30)} \closedcycle;
\draw [latex-latex](axis cs:18,0.0065) -- node [fill=blizzardblue] {$W$} (axis cs:30,0.0065);
\filldraw (18,0) circle (0.08cm);
\draw [ultra thick,blue,dashed] (18,0) -- (18,0.0099);
\node at (axis cs:21,0.017) {$A^c$};
\node at (12,0) [below, yshift=-14pt] {Train at 7:15};
\node at (30,0) [below, yshift=-14pt] {Train at 7:30};
\end{axis}
\end{tikzpicture}
\end{center}
\end{document}
答案1
您将其设置ymin为负值。实现所需结果的一种方法是将其设置ymin为 0，然后添加clip=false以确保多余的内容不会被剪掉。
\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepackage{amsmath}
\definecolor{babyblueeyes}{rgb}{0.63, 0.79, 0.95}
\definecolor{blizzardblue}{rgb}{0.67, 0.9, 0.93}
\begin{document}
\begin{center}
\begin{tikzpicture}[
declare function={
unifpdf(\x,\a,\b) = 1/(\b-\a);
}]
\begin{axis}[scale=2,
width=6.8cm, height=6cm,
axis x line = bottom,
axis x line shift=-0.008,
axis y line = left,
samples=10,
xmin=0,
xmax=35,
no marks,
scaled ticks=false,
tick label style={/pgf/number format/fixed},
xlabel=$x$,
xtick = {12,30},
xticklabels = {$5$,$20$},
xlabel style={xshift=18pt, yshift=34pt, at={(1,0)}, anchor=east},
ylabel style={rotate=-90, at={(0,1)}, anchor=south},
ymin=0,
ymax=0.05,
ytick ={0,1/30},
yticklabels={$0$,$\dfrac{1}{20}$},
ylabel=$f_X(x)$,
clip=false]
\addplot[ultra thick, smooth, domain=0:30, color=babyblueeyes]
{unifpdf(x,0,30)};
\addplot[ultra thick, ycomb, mark=o, samples at={12,30}, dashed, color=blue]{unifpdf(x,0,30)};
\addplot[draw=none, smooth, thick, domain=0:12, fill=babyblueeyes, samples=30]{unifpdf(x,0,30)} \closedcycle;
\node at (axis cs:6,0.017) {$A$};
\draw [latex-latex](axis cs:3,0.0065) -- node [fill=babyblueeyes] {$W$} (axis cs:12,0.0065);
\draw [ultra thick,blue,dashed] (3,0) -- (3,0.0099);
\filldraw (3,0) circle[radius=0.08cm];
% \draw[very thick, {Stealth}-{Stealth}] (3,0.0065) -- (12,0.0065);
\addplot[draw=none, smooth, thick, domain=12.05:30.05, fill=blizzardblue, samples=30]{unifpdf(x,0,30)} \closedcycle;
\draw [latex-latex](axis cs:18,0.0065) -- node [fill=blizzardblue] {$W$} (axis cs:30,0.0065);
\filldraw (18,0) circle[radius=0.08cm];
\draw [ultra thick,blue,dashed] (18,0) -- (18,0.0099);
\node at (axis cs:21,0.017) {$A^c$};
\node at (12,0) [below, yshift=-14pt] {Train at 7:15};
\node at (30,0) [below, yshift=-14pt] {Train at 7:30};
\end{axis}
\end{tikzpicture}
\end{center}
\end{document}
axis cs:请注意，这是一个“最小损害”解决方案。人们可以使用符号坐标作为参考，在轴外绘制额外的内容。此外，如果您使用较新的 pgfplots 版本，则不需要所有这些。