我正在尝试生成类似于此扫描示例的决策树：
请注意，有些分支的顶部和底部都有文本。我还没搞清楚该怎么做。我可以在顶部或底部显示文本，但不能同时显示两者。
我附上了一个部分解决方案。我尝试将“爆发”添加为顶部标签，将“0.060”添加为底部标签，但这会导致第一个标签消失。
\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{trees,shapes,snakes}
\usepackage{forest}
\tikzset{
decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, shape border rotate=180, outer sep=-\pgflinewidth}
}
\newsavebox\notgood
\sbox\notgood{\textbardbl}
\forestset{
declare toks={optimality}{},
sub optimal/.style={
optimality={
node [midway, sloped] {\usebox\notgood}
}
}
}
\begin{document}
\begin{frame}[fragile]
\scalebox{0.85}{
\begin{forest}
%my label/.style={
% edge label={node[auto, sloped,pos=.75,anchor=south]{#1}}
% },
my label/.style={
edge label={node[midway,above,font=\scriptsize,text width=1.5cm,align=center]{#1}}
},
my below/.style={
edge label={node[midway,below,font=\scriptsize,text width=1.5cm,align=center]{#1}}
},
for tree={
grow=0,
child anchor=west,
anchor=west,
text ragged,
inner sep=1mm,
edge={thick, draw=blue},
l sep+=30mm,
s sep+=5mm,
if n children=0{
before typesetting nodes={
label/.wrap pgfmath arg={right:#1}{content()},
content={},
leaf-chance,
},
}{},
edge path={
\noexpand\path[\forestoption{edge}]
(!u.parent anchor) -- ([xshift=-22.5mm].child anchor)\forestove{optimality} -- (.child anchor)\forestoption{edge label};
},
}
[,decision
[0.8351,chance,my label=Insure]
[,chance,my label=Don't Insure, sub optimal
[0.8394,chance,my label=No outbreak
]
[,chance,my label=Outbreak, my below=0.060
[0.8334,chance,my label=Bans only
]
[0.6663,chance,my label=Slaughter
]
]
]
]
\end{forest}
}
\end{frame}
\end{document}
我发现先前的答案对于在上方/下方之间切换很有帮助，但没有显示如何同时获得两者：https://tex.stackexchange.com/a/177254/80455
另外，这是同样的例子在决策树分支上添加短线（但问题不同）。
答案1
edge label将覆盖任何特定节点的任何先前值。因此第一个标签消失。但我们可以使用与我用于样式相同的方法，即sub optimal声明另一个选项，就像edge label然后将它添加到的重新定义中edge path。
\documentclass{beamer}
\usepackage{etex,forest}
\usetikzlibrary{shapes,snakes}
\tikzset{
decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, shape border rotate=180, outer sep=-\pgflinewidth}
}
\newsavebox\notgood
\sbox\notgood{\textbardbl}
\forestset{
declare toks={optimality}{},
sub optimal/.style={
optimality={
node [midway, sloped] {\usebox\notgood}
}
},
declare toks={edge label below}{},
}
\begin{document}
\begin{frame}[fragile]
\scalebox{0.85}{%
\begin{forest}
my label/.style={
edge label={node[midway,above,font=\scriptsize,text width=1.5cm,align=center]{#1}}
},
my below/.style={
edge label below={node[midway,below,font=\scriptsize,text width=1.5cm,align=center]{#1}}
},
for tree={
grow=0,
child anchor=west,
anchor=west,
text ragged,
inner sep=1mm,
edge={thick, draw=blue},
l sep+=30mm,
s sep+=5mm,
if n children=0{
before typesetting nodes={
label/.wrap pgfmath arg={right:#1}{content()},
content={},
leaf-chance,
},
}{},
edge path={
\noexpand\path[\forestoption{edge}]
(!u.parent anchor) -- ([xshift=-22.5mm].child anchor)\forestove{optimality} -- (.child anchor)\forestoption{edge label below}\forestoption{edge label};
},
}
[,decision
[0.8351,chance,my label=Insure]
[,chance,my label=Don't Insure, sub optimal
[0.8394,chance,my label=No outbreak
]
[,chance,my label=Outbreak, my below=0.060
[0.8334,chance,my label=Bans only
]
[0.6663,chance,my label=Slaughter
]
]
]
]
\end{forest}%
}%
\end{frame}
\end{document}
为了避免拥挤，可以允许更长的标签（增加或删除text width）或增加的值s sep。
取消以下限制text width：
my label/.style={
edge label={node[midway,above,font=\scriptsize,align=center]{#1}}
},
my below/.style={
edge label below={node[midway,below,font=\scriptsize,align=center]{#1}}
},
增加s sep：
s sep+=7.5mm,
答案2
这有点像“黑客”，但您可以简单地设置一个额外的标签，而无需使用above或below键。然后\\当您想切换到“另一行”时，它们将显示一个在上面，一个在下面。
因此基本上，您将拥有：
my abovemy belowmy label（两个都）
正如您所展示的，这是可行的。如果在某些情况下此行为会中断，请说明。
输出
代码
\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{trees,shapes,snakes}
\usepackage{forest}
\tikzset{
decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, shape border rotate=180, outer sep=-\pgflinewidth}
}
\newsavebox\notgood
\sbox\notgood{\textbardbl}
\forestset{
declare toks={optimality}{},
sub optimal/.style={
optimality={
node [midway, sloped] {\usebox\notgood}
}
}
}
\begin{document}
\begin{frame}[fragile]
\scalebox{0.85}{
\begin{forest}
my above/.style={
edge label={node[midway,above,font=\scriptsize,align=center]{#1}}
},
my below/.style={
edge label={node[midway,below,font=\scriptsize,align=center]{#1}}
},
my label/.style={
edge label={node[midway,font=\scriptsize,align=center]{#1}}
},
for tree={
grow=0,
child anchor=west,
anchor=west,
text ragged,
inner sep=1mm,
edge={thick, draw=blue},
l sep+=30mm,
s sep+=5mm,
if n children=0{
before typesetting nodes={
label/.wrap pgfmath arg={right:#1}{content()},
content={},
leaf-chance,
},
}{},
edge path={
\noexpand\path[\forestoption{edge}]
(!u.parent anchor) -- ([xshift=-22.5mm].child anchor)\forestove{optimality} -- (.child anchor)\forestoption{edge label};
},
}
[,decision
[0.8351,chance,my above=Insure]
[,chance,my below=Don't Insure, sub optimal
[0.8394,chance,my above=No outbreak
]
[,chance,my label=Outbreak\\0.060
[0.8334,chance,my above=Bans only
]
[0.6663,chance,my below=Slaughter
]
]
]
]
\end{forest}
}
\end{frame}
\end{document}