如何將圓節點置於最終收益值的中心？

Question

我試著在一些葉子上畫一個「不允許」（大X）或「劃掉」（有斜線的圓圈）標誌，如下所示：

代碼：

\documentclass[12pt]{article}
\usepackage{istgame}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows.meta, positioning}

\begin{document}
    \begin{center}
        \begin{istgame}
            \setistNewNodeStyle{max}
            [regular polygon, regular polygon sides = 3]{1.5cm}
            \setistNewNodeStyle{min}
            [regular polygon, regular polygon sides = 3, shape border rotate = 180]{1.5cm}
            \setistNewNodeStyle{chance}
            [circle]{1.2cm}
            %\xtShowTerminalNodes[box node, minimum size = 1cm]
            \def\distFactor{20};
            \xtdistance{\distFactor mm}{4*\distFactor mm}
            \setxtarrowtips[blue, thick]
            \istroot(0)[max]<center, blue>{1.5}
            \istb[blue, ->-] \istb \endist
            \xtdistance{\distFactor mm}{2*\distFactor mm}
            \istroot(1)(0-1)[chance]<center, purple>{1.5}
            \istb{0.5}[al] \istb{0.5}[ar] \endist
            \istroot(2)(0-2)[chance]<center, purple>{$\leq 1$}
            \istb{0.5}[al] \istb{0.5}[ar] \endist
            \xtdistance{\distFactor mm}{\distFactor mm}
            \istroot(3)(1-1)[min]<center, red>{2}
            \istb{}{2} \istb{}{2} \endist
            \istroot(4)(1-2)[min]<center, red>{1}
            \istb{}{1} \istb{}{2} \endist
            \istroot(5)(2-1)[min]<center, red>{0}
            \istb{}{0} \istb{}{2} \endist
            \istroot(6)(2-2)[min]
            \istb{}{-1} \istb{}{0} \endist
            \draw ([yshift = -5pt]5-2) circle (3mm);
        \end{istgame}
    \end{center}
\end{document}

輸出：

有沒有辦法繪製 X 或不允許的圓形符號，使其以葉子上的數字為中心？

Answer 1

istgame您可以透過告知這是圓形節點來添加圓形。您也可以為劃掉的圓圈定義樣式。 （路徑圖片會將這些繪製在背景上，這對於彩色文字來說看起來不太好，所以我使用append after command。）要使這項工作成功，您只需說

\istb{}{2}[[ccross]below]

代替

\istb{}{2}

結果：

\documentclass[12pt]{article}
\usepackage{geometry}
\usepackage{istgame}
\tikzset{ccross/.style={circle,draw,yshift=2pt,
append after command={
(\tikzlastnode.south west) edge[thick] (\tikzlastnode.north east)
(\tikzlastnode.south east) edge[thick] (\tikzlastnode.north west)
}}}
\begin{document}
    \begin{center}
        \begin{istgame}
            \setistNewNodeStyle{max}
            [regular polygon, regular polygon sides = 3]{1.5cm}
            \setistNewNodeStyle{min}
            [regular polygon, regular polygon sides = 3, shape border rotate = 180]{1.5cm}
            \setistNewNodeStyle{chance}
            [circle]{1.2cm}
            %\xtShowTerminalNodes[box node, minimum size = 1cm]
            \def\distFactor{20};
            \xtdistance{\distFactor mm}{4*\distFactor mm}
            \setxtarrowtips[blue, thick]
            \istroot(0)[max]<center, blue>{1.5}
            \istb[blue, ->-] \istb \endist
            \xtdistance{\distFactor mm}{2*\distFactor mm}
            \istroot(1)(0-1)[chance]<center, purple>{1.5}
            \istb{0.5}[al] \istb{0.5}[ar] \endist
            \istroot(2)(0-2)[chance]<center, purple>{$\leq 1$}
            \istb{0.5}[al] \istb{0.5}[ar] \endist
            \xtdistance{\distFactor mm}{\distFactor mm}
            \istroot(3)(1-1)[min]<center, red>{2}
            \istb{}{2} \istb{}{2} \endist
            \istroot(4)(1-2)[min]<center, red>{1}
            \istb{}{1} \istb{}{2} \endist
            \istroot(5)(2-1)[min]<center, red>{0}
            \istb{}{0} \istb{}{2}[[ccross]below] \endist
            \istroot(6)(2-2)[min]
            \istb{}{-1} \istb{}{0} \endist
        \end{istgame}
    \end{center}
\end{document}