%% file: istgame.sty
%%
%% Drawing Game Trees with TikZ
%%
%% (C) Copyright 2015-2022 In-Sung Cho <ischo at ktug.org>
%%
%% This work may be distributed and/or modified 
%% under the conditions of the LaTeX Project Public License, 
%% either version 1.3c of this license or (at your option) any later version.
%% The latest version of this license is in
%%  http://www.latex-project.org/lppl.txt.
%%
%% -------------------------------------------------
\ProvidesPackage{istgame}[2022/03/22 v2.1 Draw Game Trees with TikZ]

% expl3,xparse: LPPL
% tikz: LPPL and/or GNU GPL
\RequirePackage{expl3,xparse,tikz}
\usetikzlibrary
{ 
    trees , calc , arrows , shapes , positioning ,
    backgrounds ,              % for information sets and subgames
    fit ,                      % for \xtSubgameBox(Oval)
    decorations.markings ,     % for \xtShowArrows and middle arrows
    patterns , intersections , % for additional use
    arrows.meta , bending      % added in version 2.1
}

% backgrounds
\pgfdeclarelayer{background}
\pgfdeclarelayer{behind}
\pgfdeclarelayer{above}
\pgfdeclarelayer{foreground}

\pgfsetlayers{background,behind,main,above,foreground}


%% prefixes for macros and defaults
% \ist<...> stands for "an insung's simple tree" (or "it's a simple tree")
% \xt<...> stands for "extensive tree"
% \xtCI stands for "curved information set"
% \cntm<...> stands for "continuum"
% \cntmA<...> stands for "continuum arc"
% \istdefault@<...>
% \xtdefault@<...>
% \xtCI@default@<...>
% \cntm@default@<...>
% \cntmA@default@<...>


%% node styles

\ExplSyntaxOn

% basics (in node styles)
\def\istdefault@node@innersep{1pt}    %% default node inner sep
\def\istdefault@node@outersep{0pt}    %% default node outer sep
\def\istdefault@node@drawcolor{black} %% default node color
\def\istdefault@node@fillcolor{white} %% default node background color
% (can be used in preamble)
\newcommand*\setistdefaultnodeinnersep[1]{\renewcommand*\istdefault@node@innersep{#1}}
\newcommand*\setistdefaultnodeoutersep[1]{\renewcommand*\istdefault@node@outersep{#1}}
\newcommand*\setistdefaultnodefillcolor[1]{\renewcommand*\istdefault@node@fillcolor{#1}}
\newcommand*\setistdefaultnodedrawcolor[1]{\renewcommand*\istdefault@node@drawcolor{#1}}

% plain node: definition
\newcommand*\istplainnodeinnersep { \istdefault@node@innersep } % 1pt by default
\newcommand*\istplainnodeoutersep { \istdefault@node@outersep } % 0pt by default

% {inner sep} {outer sep}
\NewDocumentCommand \setistPlainNodeStyle
{ G{\istdefault@node@innersep} G{\istdefault@node@outersep} }
{
    \renewcommand*\istplainnodeinnersep {#1} % 1pt by default
    \renewcommand*\istplainnodeoutersep {#2} % 0pt by default
}
\tikzset{ plain~node /.style =
    {  
      draw = none ,
      inner~sep = \istplainnodeinnersep , outer~sep = \istplainnodeoutersep
    } 
}

% null node: definition
\newcommand*\istnullnodedrawcolor { \istdefault@node@drawcolor } % (#1) black
\def\istdefault@null@nodesize { .2pt } % default of (#2)
\def\istdefault@null@node@fillcolor { \istnullnodedrawcolor } % fill color = draw color
\newcommand*\istnullnodesize { \istdefault@null@nodesize } % (#2)
\newcommand*\istnullnodefillcolor { \istdefault@node@drawcolor } % (#3)  <= black (o.k.)
\newcommand*\istnullnodefillopacity { 1 } % (#4)

% [draw color] {minimum size} [fill color] [fill opacity]
\NewDocumentCommand \setistNullNodeStyle
{ O{\istdefault@node@drawcolor} G{\istdefault@null@nodesize} O{\istdefault@null@node@fillcolor} O{1} }
{
    \renewcommand*\istnullnodedrawcolor{#1}
    \renewcommand*\istnullnodesize{#2}        % .2pt by default
    \IfNoValueTF {#3}
    {
      \renewcommand*\istnullnodefillcolor{#1} % same as {#1} with default black
    }
    {
      \renewcommand*\istnullnodefillcolor{#3}
    }
    \renewcommand*\istnullnodefillopacity{#4}
}
\tikzset{ null~node /.style = 
    {
      circle , draw , thin , solid , 
      inner~sep = 0pt , outer~sep = \istdefault@node@outersep ,
      minimum~size = \istnullnodesize ,
      draw = \istnullnodedrawcolor ,
      fill = \istnullnodedrawcolor ,
      fill~opacity = \istnullnodefillopacity
    }
}

% solid node: definition
\newcommand*\istsolidnodedrawcolor { \istdefault@node@drawcolor } % (#1) black
\def\istdefault@solid@node@size { 2.4pt } % default of (#2)
\def\istdefault@solid@node@fillcolor { \istsolidnodedrawcolor }
\newcommand*\istsolidnodesize { \istdefault@solid@node@size } % (#2)
\newcommand*\istsolidnodefillcolor { \istdefault@solid@node@fillcolor } % (#3)  <= black (o.k.)
\newcommand*\istsolidnodefillopacity { 1 } % (#4)

% [draw color] {minimum size} [fill color] [fill opacity]
\NewDocumentCommand \setistSolidNodeStyle
{ O{\istdefault@node@drawcolor} G{\istdefault@solid@node@size} O{\istdefault@solid@node@fillcolor} O{1} }
{
    \renewcommand*\istsolidnodedrawcolor{#1}
    \renewcommand*\istsolidnodesize{#2}
    \IfNoValueTF {#3}
    {
      \renewcommand*\istsolidnodefillcolor{#1} % same as {#1} with default black
    }
    {
      \renewcommand*\istsolidnodefillcolor{#3}
    }
    \renewcommand*\istsolidnodefillopacity{#4}
}
\tikzset{ solid~node /.style = 
    {
      circle , draw , thin , solid , 
      inner~sep = 0pt , outer~sep = \istdefault@node@outersep ,
      minimum~size = \istsolidnodesize ,
      draw = \istsolidnodedrawcolor , 
      fill = \istsolidnodefillcolor ,
      fill~opacity = \istsolidnodefillopacity
    }
}

% decision node & terminal node
\let\setistDecisionNodeStyle\setistSolidNodeStyle
\let\setistTerminalNodeStyle\setistSolidNodeStyle

% hollow node: definition
\newcommand*\isthollownodedrawcolor { \istdefault@node@drawcolor } % (#1) black
\def\istdefault@hollow@node@size { 2.8pt } % default of (#2)
\newcommand*\isthollownodesize { \istdefault@hollow@node@size } % (#2)
\newcommand*\isthollownodefillcolor { \istdefault@node@fillcolor } % (#3) white
\newcommand*\isthollownodefillopacity { 1 } % (#4)

% [draw color] {minimum size} [fill color] [fill opacity]
\NewDocumentCommand \setistHollowNodeStyle
{ O{\istdefault@node@drawcolor} G{\istdefault@hollow@node@size} O{\istdefault@node@fillcolor} O{1} }
{
    \renewcommand*\isthollownodedrawcolor{#1}
    \renewcommand*\isthollownodesize{#2}
    \renewcommand*\isthollownodefillcolor{#3}
    \renewcommand*\isthollownodefillopacity{#4}
}
\tikzset{ hollow~node /.style = 
    {
      circle , draw , thin , solid ,
      inner~sep = 0pt , outer~sep = \istdefault@node@outersep ,
      minimum~size = \isthollownodesize ,
      draw = \isthollownodedrawcolor ,
      fill = \isthollownodefillcolor ,
      fill~opacity = \isthollownodefillopacity
    }
}

% initial node & chance node
\let\setistInitialNodeStyle\setistHollowNodeStyle
\let\setistChanceNodeStyle\setistHollowNodeStyle

% rectangle node: definition
\newcommand*\istrectanglenodedrawcolor { \istdefault@node@drawcolor } %(#1) black
\def\istdefault@rectangle@node@size { 4pt } % default of (#2)
\newcommand*\istrectanglenodesize { \istdefault@rectangle@node@size } % (#2)
\newcommand*\istrectanglenodefillcolor { \istdefault@node@fillcolor } % (#3) white
\newcommand*\istrectanglenodefillopacity { 1 } % (#4)

% [draw color] {minimum size} [fill color] [fill opacity]
\NewDocumentCommand \setistRectangleNodeStyle
{ O{\istdefault@node@drawcolor} G{\istdefault@rectangle@node@size} O{\istdefault@node@fillcolor} O{1} }
{
    \renewcommand*\istrectanglenodedrawcolor{#1}
    \renewcommand*\istrectanglenodesize{#2}
    \renewcommand*\istrectanglenodefillcolor{#3}
    \renewcommand*\istrectanglenodefillopacity{#4}
}
\tikzset{ rectangle~node /.style = 
    {
      rectangle , draw , thin , solid , 
      inner~sep = 2pt , outer~sep = \istdefault@node@outersep ,
      minimum~size = \istrectanglenodesize ,
      draw = \istrectanglenodedrawcolor ,
      fill = \istrectanglenodefillcolor ,
      fill~opacity = \istrectanglenodefillopacity
    }
}

% box node & square node
\let\setistBoxNodeStyle\setistRectangleNodeStyle
\let\setistSquareNodeStyle\setistRectangleNodeStyle

% ellipse node: definition
\newcommand*\istellipsenodedrawcolor { \istdefault@node@drawcolor } % (#1) black
\def\istdefault@ellipse@node@size { 4.8pt } % default of (#2)
\newcommand*\istellipsenodesize { \istdefault@ellipse@node@size } % (#2)
\newcommand*\istellipsenodefillcolor { \istdefault@node@fillcolor } % (#3) white
\newcommand*\istellipsenodefillopacity { 1 } % (#4)

\NewDocumentCommand \setistEllipseNodeStyle
{ O{\istdefault@node@drawcolor} G{\istdefault@ellipse@node@size} O{\istdefault@node@fillcolor} O{1} }
{
    \renewcommand*\istellipsenodedrawcolor{#1}
    \renewcommand*\istellipsenodesize{#2}
    \renewcommand*\istellipsenodefillcolor{#3}
    \renewcommand*\istellipsenodefillopacity{#4}
}
\tikzset{ ellipse~node /.style = 
    {
      ellipse , draw , thin , solid ,
      inner~sep = 1.5pt , outer~sep = \istdefault@node@outersep ,
      minimum~size = \istellipsenodesize ,
      draw = \istellipsenodedrawcolor ,
      fill = \istellipsenodefillcolor ,
      fill~opacity = \istellipsenodefillopacity
    }
}

% oval node
\let\setistOvalNodeStyle\setistEllipseNodeStyle


%% aliases: node styles
\tikzset{ initial~node  /.style = hollow~node }
\tikzset{ chance~node   /.style = hollow~node }
\tikzset{ decision~node /.style = solid~node }     % decision nodes
\tikzset{ terminal~node /.style = solid~node }     % terminal nodes
\tikzset{ box~node      /.style = rectangle~node }
\tikzset{ square~node   /.style = rectangle~node }
\tikzset{ oval~node     /.style = ellipse~node }


% \setistNewNodeStyle
% {node name} [node opt] {minimum size}
\NewDocumentCommand \setistNewNodeStyle { m O{} G{6mm} }
{
    \tikzset
    { #1 /.style =
      {
        - , circle , thin , solid , 
        inner~sep = \istdefault@node@innersep ,
        minimum~size = #3 ,
        draw = \istdefault@node@drawcolor , 
        fill = \istdefault@node@fillcolor ,
        #2
      }
    }
}


%% input mode changer: (math mode True/False) - owner, action labels, payoff

% owner: (default: mathfalse)

\newcount\istmathflagowner
\def\istownermathtrue  { \istmathflagowner = 1 } 
\def\istownermathfalse { \istmathflagowner = 0 }
\istownermathfalse % default declared : mathfalse

% owner text font
\newcommand*\istownertextfont [1] { \def\ist@owner@text@font {#1} }
\istownertextfont { }

% \istownerstyle
\NewDocumentCommand \istownerstyle { m }
{
  	\int_compare:nTF { \istmathflagowner == 1 }
    {	\ensuremath {#1} }
  	{
	    \tl_if_empty:NF \ist@owner@text@font 
	    { \exp_args:No \use:c { \ist@owner@text@font } } {#1} % owner text font
	  }
}

% action labels: (default: mathtrue)

\newcount\istmathflagactionlabel
\newcommand*\istactionlabelmathtrue  { \istmathflagactionlabel = 1 }
\newcommand*\istactionlabelmathfalse { \istmathflagactionlabel = 0 }
\istactionlabelmathtrue % default declared : mathtrue

% action labels text font
% used for automatic "italics" for action labels (with \setistmathTF*001 -- second zero)
\newcommand*\istactionlabeltextfont [1] { \def\ist@actionlabel@text@font {#1} }
\istactionlabeltextfont { }

% \istactionlabelstyle
\NewDocumentCommand \istactionlabelstyle{m}
{
  \int_compare:nTF { \istmathflagactionlabel == 1 }
  { \ensuremath {#1} }
  {
    \tl_if_empty:NF \ist@actionlabel@text@font
    { \exp_args:No \use:c { \ist@actionlabel@text@font } } {#1} % AL text font
  }
}

% payoffs: (default: mathtrue)

\newcount\istmathflagpayoff
\newcommand*\istpayoffmathtrue  { \istmathflagpayoff = 1 }
\newcommand*\istpayoffmathfalse { \istmathflagpayoff = 0 }
\istpayoffmathtrue % default declared : mathtrue

% payoff text font
% (not used)
\newcommand*\istpayofftextfont [1] { \def\ist@payoff@text@font {#1} }
\istpayofftextfont { }

% \istpayoffstyle
\NewDocumentCommand \istpayoffstyle{m}
{
  \int_compare:nTF { \istmathflagpayoff == 1 }
  { \ensuremath {#1} }
  {
    \tl_if_empty:NF \ist@payoff@text@font
    { \exp_args:No \use:c { \ist@payoff@text@font } } {#1} % payoff text font
  }
}

% \setistmathTF(*)
% * {} {} {} <owner font> {action labels font} [payoff font]
\NewDocumentCommand \setistmathTF{ s m m m D<>{} G{textit} O{} }
{ 
  \int_compare:nTF { #2 == 1 } { \istownermathtrue }       { \istownermathfalse }
  \int_compare:nTF { #3 == 1 } { \istactionlabelmathtrue } { \istactionlabelmathfalse }
  \int_compare:nTF { #4 == 1 } { \istpayoffmathtrue }      { \istpayoffmathfalse }
  \IfBooleanT {#1}
  {
	  \istownertextfont { #5 }
	  \istactionlabeltextfont { #6 }
	  \istpayofftextfont { #7 }
  }
}


%% fine tuning: labels (experimental)
\newcommand*\xtALxShift{0pt}  % default xshift
\newcommand*\xtALyShift{0pt}  % default yshift

\NewDocumentCommand \xtALPush { m m }
{
    \renewcommand*\xtALxShift{#1}
    \renewcommand*\xtALyShift{#2}
}

\newcommand*\istactionlabelxshift{1pt}  % default horizontal push (alternatively, .67pt)
\newcommand*\istactionlabelyshift{2pt}  % default vertical   push (alternatively, 2.5pt)

\NewDocumentCommand \xtALShift { G{\istactionlabelxshift} G{\istactionlabelyshift} }
{
    \renewcommand*\istactionlabelxshift{#1}
    \renewcommand*\istactionlabelyshift{#2}
}


%% node anchors (experimental, used only in test, not documented)
\let\istparentanchor\tikzparentanchor % empty by default
\let\istchildanchor\tikzchildanchor   % empty by default
\newcommand*\setistparentanchor [1] { \renewcommand*\istparentanchor{.#1} }
\newcommand*\setistchildanchor  [1] { \renewcommand*\istchildanchor{.#1}  }

\NewDocumentCommand \setistbranchanchors{ m G{center} }
{
    \renewcommand*\istparentanchor {.#1}
    \renewcommand \istchildanchor  {.#2}
}


%%%%%%%%%%%%%%%%%
%% istgame macros
%%%%%%%%%%%%%%%%%

%% basics (in child)
% -- used in the definition of \istb and its variants
\def\xt@ndot{node[solid~node]{}} % (within child) default node dot: decision node
\def\xt@show@tndot{}             % default: no terminal nodes printed
\def\xt@show@endpoint{}          % default: no endpoints printed
\def\cntm@ndot{}                 % default: no cntm node dot printed
\def\cntm@show@endpoint{}        % default: no cntm endpoint printed


\ExplSyntaxOff

%%-----------------
%% expl3 up to here (paused, because of colon problem)
%%-----------------


%% payoffs


%---syntaxoff-----
% remark: label={[opt]pos:{text}}  (needed this form for \istgrowdirection to put payoffs)
\NewDocumentCommand \istpayoff{ m +m }
{
  node [ inner sep = 0pt , text depth = .25ex , 
         label = {#1:\istpayoffstyle{#2} } ] {}                                  % colon here
}

%---syntaxoff-----
% \ISTRoot
% (used in \istroot)
% ' [grow] (root) (at) [node] <angle> {owner} +levdist..sibdist+
\NewDocumentCommand \ISTRoot
{ t' O{south} r() D(){0,0} O{} D<>{} G{} D+.{\xtlevdist} D.+{\xtsibdist} } 
{ 
    \IfBooleanTF {#1}
    {
    \tikzset{level 1/.style = { level distance = #8 , sibling distance = #9 } }  % colon here
    \node (#3) at (#4) [decision node , #5 , label = {#6:{#7} } ] 
                       {} [ \xt@growswap=#2 ] 
    }
    {
    \tikzset{level 1/.style = { level distance = #8 , sibling distance = #9 } }  % colon here
    \node (#3) at (#4) [ decision node , #5 , label = {#6:{#7} } ] 
                       {} [ \xt@grow=#2 ]    
    }
}


%%-----------------
%% expl3 from here again
%%-----------------

\ExplSyntaxOn

%% main macros: \xtdistance, \ISTRoot(O), \ISTCntm(Arc)

\def\xtdefault@levdist {15mm}                %% (default) level distance   : 15mm
\def\xtdefault@sibdist {\xtdefault@levdist}  %% (default) sibling distance : 15mm
\newcommand*\xtlevdist {\xtdefault@levdist}
\newcommand*\xtsibdist {\xtdefault@sibdist}

\NewDocumentCommand \xtdistance
{ O{1} m G{\xtdefault@sibdist} }
{
    \renewcommand*\xtlevdist {#2}
    \renewcommand*\xtsibdist {#3}
    \tikzset{ level~#1/.style = {level~distance = \xtlevdist , sibling~distance = \xtsibdist } }
}


%% counterclockwise (grow=) or clockwise (grow'=)

% default: growing south counterclockwise
\def\xt@grow { grow }
\def\xt@growswap { grow' }
\def\istdefault@grow { south } % tree growing direction

% \setxtgrowkey %% just for one simple tree
\NewDocumentCommand \setxtgrowkey { m }
{ 
    \renewcommand*\xt@grow {#1}
}

% growsawp call test
\bool_new:N \xt_growswap_call_bool 
\bool_set_false:N \xt_growswap_call_bool

% \setistgrowdirection %% for whole tree
\NewDocumentCommand \setistgrowdirection{ t' m }
{ \IfBooleanTF {#1}
    {
      \bool_set_true:N \xt_growswap_call_bool
      \renewcommand*\xt@grow { grow' }
      \renewcommand*\istdefault@grow {#2}
    }
    {
      \renewcommand*\xt@grow { grow }
      \renewcommand*\istdefault@grow {#2}
    }
}


% \ISTRootO (oval version)
% (used in \istrooto)
% ' [grow] (root) (at) [node] <angle> {owner} +levdis..sibdist+
\NewDocumentCommand \ISTRootO
{ t' O{south} r() D(){0,0} O{} D<>{} G{} D+.{\xtlevdist} D.+{\xtsibdist} } 
{ 
    \IfBooleanTF {#1}
    {
    \tikzset { level~1/.style = { level~distance = #8 , sibling~distance = #9} }
    \node (#3) at (#4) [ oval~node , #5 ] {#7} [ \xt@growswap = #2 ]
    }
    {
    \tikzset { level~1/.style = { level~distance = #8 , sibling~distance = #9 } }
    \node (#3) at (#4) [ oval~node , #5 ] {#7} [ \xt@grow = #2 ]
    }
}

%% istgame environment (can be used in the preamble)

\def\istgame@default@fontsize { \normalsize }
\def\istgame@default@arrowend@shorten { 0pt } % 0pt needed, otherwise affects all the lines

\NewDocumentCommand \setistgamefontsize { m } 
{
    \renewcommand*{\istgame@default@fontsize} {#1}
}

\NewDocumentCommand \setistgameshorten { m }
{
    \renewcommand*{\istgame@default@arrowend@shorten} {#1}
}

%% (2021/04/09)
%% more global macros (can be used in the preamble)

\NewDocumentCommand \setistsolidnodesize { m } 
{
    \renewcommand*{\istdefault@solid@node@size} {#1}
}

\NewDocumentCommand \setisthollownodesize { m } 
{
    \renewcommand*{\istdefault@hollow@node@size} {#1}
}

\NewDocumentCommand \setistellipsenodesize { m } 
{
%    \renewcommand*{\istdefault@ellipse@node@size} {#1}
    \renewcommand*{\istellipsenodesize} {#1}
}

\NewDocumentCommand \setistrectagnlenodesize { m } 
{
    \renewcommand*{\istdefault@rectangle@node@size} {#1}
}


% get ready for checking (x)(y)scale option
\clist_new:N \l_parseopt_clist

% \xtxscale
\cs_new_nopar:Npn \get_xscale_option_string:n #1
{
  	\get_opt_xvalue:w #1\q_stop
}
\cs_new_nopar:Npn \get_opt_xvalue:w #1=#2\q_stop
{
  	% keep the value of xscale
  	\tl_gset:Nn \xtxscale { #2 }
}

% \xtyscale
\cs_new_nopar:Npn \get_yscale_option_string:n #1
{
  	\get_opt_yvalue:w #1\q_stop
}
\cs_new_nopar:Npn \get_opt_yvalue:w #1=#2\q_stop
{
  	% keep the value of yscale
  	\tl_gset:Nn \xtyscale { #2 }
}

% \xtscale
\cs_new_nopar:Npn \get_scale_option_string:n #1
{
  	\get_opt_value:w #1\q_stop
}
\cs_new_nopar:Npn \get_opt_value:w #1=#2\q_stop
{
  	% keep the value of scale
  	\tl_gset:Nn \xtscale { #2 }
}


% to resolve TikZ problem: sloped label conflict with x-y-scale
% temporary solution (experimental)

% \xtcureslopedlabelsNS (for north and south growing tree)
\NewDocumentCommand \xtcureslopedlabelsNS { }
{
    \istgameScaleCallTestAndAdjust
    \bool_if:NTF \xt_xscale_call_bool
    {
        \pgfmathsetmacro\xtsibdistadj {\xtxscale*\xtsibdist}
        \pgfmathsetmacro\xtlevdistadj {1*\xtlevdist}
    }
    {
      \bool_if:NT \xt_yscale_call_bool
      {
        \pgfmathsetmacro\xtsibdistadj {1*\xtsibdist}
        \pgfmathsetmacro\xtlevdistadj {\xtyscale*\xtlevdist}
      }
    }
    \xtdistance{\xtlevdistadj}{\xtsibdistadj}
}

% \xtcureslopedlabelsEW (for east and west growing tree)
\NewDocumentCommand \xtcureslopedlabelsEW { }
{
    \istgameScaleCallTestAndAdjust
    \bool_if:NTF \xt_xscale_call_bool
    {
        \pgfmathsetmacro\xtsibdistadj {1*\xtsibdist}
        \pgfmathsetmacro\xtlevdistadj {\xtxscale*\xtlevdist}
    }
    {
      \bool_if:NT \xt_yscale_call_bool
      {
        \pgfmathsetmacro\xtsibdistadj {\xtyscale*\xtsibdist}
        \pgfmathsetmacro\xtlevdistadj {1*\xtlevdist}
      }
    }
    \xtdistance{\xtlevdistadj}{\xtsibdistadj}
}


%%% istgame: main environment
\DeclareDocumentEnvironment {istgame} { s O{} }   % accepts tikzpicture options
{
    % call set (false)
    \bool_set_false:N \cntm_distance_call_bool            % to distinguish cntm sibdist
    \bool_set_false:N \cntm_act_sibdist_call_bool         %    from cntm action sibdist
    \bool_set_false:N \xt_xscale_call_bool                % for InfosetO, CInfosetO, and more
    \bool_set_false:N \xt_yscale_call_bool                % for InfosetO, CInfosetO, and more
    \bool_set_false:N \xt_scale_call_bool                 % for InfosetO, CInfosetO, and more
    \bool_set_false:N \_arrow_option_exist_bool           % for arrow shorten
    \bool_set_false:N \xt_growswap_call_bool              % for CInfoset(O)
    \bool_set_false:N \_istroot_cntmA_call_bool           % for \istbA
    \bool_set_false:N \_istroot_cntm_call_bool            % for \istbA
    \bool_set_false:N \_xt_levdist_local_call_bool        % for \istbA
    \bool_set_false:N \_cntm_distance_local_call_bool     % for \istbA
    \bool_set_false:N \_cntmA_distance_local_call_bool    % for \istbA
    
  \IfBooleanTF { #1 }
  {
    \def\xtxscale{1}
    \def\xtyscale{1}
    \def\xtscale{1}
    
    \def\xtcureslopedlabelsNS{}
    \def\xtcureslopedlabelsEW{}
  
    \begin{tikzpicture} [ #2 ]
  }
  {
    % extract the value of xscale/yscale/scale
    % (extract scale value, only if it is used alone)
    \clist_set:Nn \l_parseopt_clist { #2 }
    \tl_gset:Nn \xtxscale {1.0}
    \tl_gset:Nn \xtyscale {1.0}
    \tl_gset:Nn \xtscale {1.0}
    \clist_map_inline:Nn \l_parseopt_clist 
    {
      \str_if_in:nnTF { ##1 } { xscale }
      {
        \bool_set_true:N \xt_xscale_call_bool
        \get_xscale_option_string:n { ##1 }
        \str_if_in:nnT { ##1 } {yscale}
        {
          \bool_set_true:N \xt_yscale_call_bool
          \get_yscale_option_string:n { ##1 }        
        }
      }
      { 
        \str_if_in:nnTF { ##1 } { yscale }
        {
          \bool_set_true:N \xt_yscale_call_bool
          \get_yscale_option_string:n { ##1 }
          \str_if_in:nnT {##1} { xscale }
          {
            \bool_set_true:N \xt_xscale_call_bool
            \get_xscale_option_string:n { ##1 }          
          }
        }
        { % xscale:false, yscale:false
          \str_if_in:nnT { ##1 } { scale }
          {
            \bool_set_true:N \xt_scale_call_bool
            \get_scale_option_string:n { ##1 }
          }
        }
      }       
    }

  	\clist_if_in:NnT \l_parseopt_clist { -> } % check if [->] exists
  	{
	    \bool_set_true:N \_arrow_option_exist_bool
  		\clist_remove_all:Nn \l_parseopt_clist { -> }
  		\clist_put_left:No \l_parseopt_clist { -> , shorten~> = \istgame@default@arrowend@shorten }
  	}

  	\tl_set:Nn \l_tmpa_tl { font = \istgame@default@fontsize , > = stealth , }
    \tl_put_right:Nx \l_tmpa_tl { \clist_use:Nn \l_parseopt_clist { , } }
    
    \exp_last_unbraced:NnNo 
    \begin{tikzpicture} [ \l_tmpa_tl ]
  }
}
{
  	\end{tikzpicture}
}
%%%  % add the following as env option: tikz-qtree conflict resolution
%%%    edge~from~parent~path = { (\tikzparentnode) -- (\tikzchildnode) }


%% scale call test and adjust

\def\xtinfosetheightvar   {\xtinfosetheight}
\def\cntminfosetheightvar {\cntminfosetheight}

% \istgameScaleCallTestAndAdjust
% use this only in a GROUP
\NewExpandableDocumentCommand \istgameScaleCallTestAndAdjust { }
{
    \bool_if:NTF \xt_xscale_call_bool 
    { 
      \pgftransformxscale{1/\xtxscale}
      % keep going for yscale
      \bool_if:NT \xt_yscale_call_bool
      {
        \pgftransformyscale{1/\xtyscale} 
      }
      % for scaling infosetO if scaled together with x-y-scale
      \renewcommand*\xtinfosetheightvar   {\xtinfosetheight*\xtscale}
      \renewcommand*\cntminfosetheightvar {\cntminfosetheight*\xtscale}
    }
    {
      \bool_if:NTF \xt_yscale_call_bool 
      { 
        \pgftransformyscale{1/\xtyscale}
        % keep going for xscale
        \bool_if:NT \xt_xscale_call_bool
        {
          \pgftransformxscale{1/\xtxscale} 
        }
        % for scaling infosetO if scaled together with x-y-scale
        \renewcommand*\xtinfosetheightvar   {\xtinfosetheight*\xtscale}
        \renewcommand*\cntminfosetheightvar {\cntminfosetheight*\xtscale}
      }
      { 
        \bool_if:NT \xt_scale_call_bool 
        { 
          % no scaling infosetO if scaled without x-y-scale
          \pgftransformscale{1/\xtscale}
        }
      }
    }
}


%% ---------------
%% core macro part
%% ---------------

% get ready
\tl_new:N \ischo_game_tl

% action (with abbreviations)
% BE CAREFUL: each case has different options (do not try to shorten)
% {#1: branch line style} {#2: position} {#3: action labels}
\cs_new:Npn \ist_move:nnn #1 #2 #3
{
%    \str_case_e:nnF { #2 }
    \str_case:nnF { #2 }
    {
      { al } {
               edge~from~parent [ #1 ] 
               node [ above~left , text~depth = .25ex , 
                      xshift = \istactionlabelxshift ,  yshift = -\istactionlabelyshift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { ar } {
               edge~from~parent [ #1 ] 
               node [ above~right , text~depth = .25ex , 
                      xshift = -\istactionlabelxshift , yshift = -\istactionlabelyshift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { bl } {
               edge~from~parent [ #1 ] 
               node [ below~left , text~depth = .25ex , 
                      xshift = \istactionlabelxshift ,  yshift = \istactionlabelyshift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { br } {
               edge~from~parent [ #1 ] 
               node [ below~right , text~depth = .25ex , 
                      xshift = -\istactionlabelxshift , yshift = \istactionlabelyshift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { l }  {
               edge~from~parent [ #1 ] 
               node [ left , text~depth = .25ex ,  xshift = -\xtALxShift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { r }  { 
               edge~from~parent [ #1 ] 
               node [ right , text~depth = .25ex , xshift = \xtALxShift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { a }  { 
               edge~from~parent [ #1 ] 
               node [ above , text~depth = .25ex , yshift = \xtALyShift ] 
                    { \istactionlabelstyle{#3} } 
             }
      { b }  { 
               edge~from~parent [ #1 ] 
               node [ below , text~depth = .25ex , yshift = -\xtALyShift ] 
                    { \istactionlabelstyle{#3} } 
             }
    }
    {
        edge~from~parent [ #1 ] 
               node [ text~depth = .25ex , #2 ] { \istactionlabelstyle{#3} }  % was \istmove{#1}{#2}{#3}
    }
}

% payoff (with abbreviations)
% {#1: position} {#2: payoffs}
\cs_new:Npn \ist_payoff:nn #1 #2
{
%    \str_case_e:nnF { #1 }
    \str_case:nnF { #1 }
    {
      { al } { \istpayoff { above~left }  { #2 } }
      { ar } { \istpayoff { above~right } { #2 } }
      { bl } { \istpayoff { below~left }  { #2 } }
      { br } { \istpayoff { below~right } { #2 } }
      { l }  { \istpayoff { left }        { #2 } }
      { r }  { \istpayoff { right }       { #2 } }
      { a }  { \istpayoff { above }       { #2 } }
      { b }  { \istpayoff { below }       { #2 } }
    }
    {
      \istpayoff { #1 } { #2 }
    }
}


%% core macros: \istroot, \istb, \endist

% \istroot(') -- standard version
% ' [grow, tree opt] (root) (at) [node style] <angle> {owner} +levdis..sibdist+
\NewDocumentCommand \istroot 
{ t' O{\istdefault@grow} r() D(){0,0} O{} D<>{above} G{} d+. D.+{\xtsibdist} }
{
    % for \istbA
    \IfNoValueTF {#8} 
    { % if the third option exists in \cntmdistance(*)
      \bool_set_false:N \_xt_levdist_local_call_bool 
      \tl_set:Nn \_xt_levdist_local_tl { \xtlevdist } 
      \tl_set:Nn \_xt_sibdist_local_tl { \xtsibdist } 
    }
    { 
      \bool_set_true:N \_xt_levdist_local_call_bool
      \tl_set:Nn \_xt_levdist_local_tl { #8 } 
      \tl_set:Nn \_xt_sibdist_local_tl { #9 } 
    }
    % normal process
    \tl_clear:N \ischo_game_tl
    \xdef\istgrowdirection{#2}  % used in \istb to specify [payoff direction]

    \IfBooleanTF {#1}
    { 
      \tl_put_right:Nn \ischo_game_tl { \ISTRoot' }
    }
    { 
      \tl_put_right:Nn \ischo_game_tl { \ISTRoot }
    }

    \tl_put_right:Nx  \ischo_game_tl  { [ \istgrowdirection ] ( #3 ) ( #4 ) [ #5 ] < #6 > }
    \tl_put_right:Nn  \ischo_game_tl  { { \istownerstyle{ #7 } } }
    \tl_put_right:Nx  \ischo_game_tl  { + { \_xt_levdist_local_tl } .. { #9 } + }
                                      % { } needed for #8 and #9 with decimal dim
}

% \istrooto(') -- oval version
% ' [grow] (root) (at) [node style] <angle> {owner} +levdis..sibdist+  --- <angle>: redundant
\NewDocumentCommand \istrooto
{ t' O{\istdefault@grow} r() D(){0,0} O{} D<>{above} G{} d+. D.+{\xtsibdist} }
{
    % for \istbA
    \IfNoValueTF {#8} 
    { 
      \bool_set_false:N \_xt_levdist_local_call_bool 
      \tl_set:Nn \_xt_levdist_local_tl { \xtlevdist } 
      \tl_set:Nn \_xt_sibdist_local_tl { \xtsibdist } 
    }
    { 
      \bool_set_true:N \_xt_levdist_local_call_bool
      \tl_set:Nn \_xt_levdist_local_tl { #8 } 
      \tl_set:Nn \_xt_sibdist_local_tl { #9 } 
    }
    % normal process    
    \tl_clear:N \ischo_game_tl
    \xdef\istgrowdirection{#2}  % used in \istb to specify [payoff direction]

    \IfBooleanTF {#1}
    { 
      \tl_put_right:Nn \ischo_game_tl { \ISTRootO' }
    }
    { 
      \tl_put_right:Nn \ischo_game_tl { \ISTRootO }
    }

    \tl_put_right:Nx  \ischo_game_tl  { [ \istgrowdirection ] ( #3 ) ( #4 ) [ #5 ] }
    \tl_put_right:Nn  \ischo_game_tl  { { \istownerstyle { #7 } } }
    \tl_put_right:Nx  \ischo_game_tl  { + { \_xt_levdist_local_tl } .. { #9 } + }
                                      % { } needed for #8 and #9 with decimal dim
}

% \istbm % missing version
\NewDocumentCommand \istbm { }
{
    \istb<missing>
}

% \istbm % missing version (just in case)
\NewDocumentCommand \istbAm { }
{
    \istbA<missing>
}


% \istb(*)
% * (redundant) <grow,xtdistances> [line style] {action labels} [pos] {payoffs} [pos]
% second option is redundant (this helps not getting errors when playing with \istbA)
% default payoff postion: \istgrowdirection 
\NewDocumentCommand \istb 
{ s D(){1} D<>{} O{} +G{} O{} +g O{\istgrowdirection} }
{ 
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ #3 ] 
      { 
        \IfBooleanTF  { #1 } { \xt@ndot } { \xt@show@endpoint }
        \IfValueT     { #7 } { \ist_payoff:nn { #8 } { #7 } }
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow , #4 } { #6 } { #5 } 
      }
    }
}

% \istbt(*)  % terminal version
% this is the replacement of \istb.(*)
% * (redundant) <grow,xtdistances> [line style] {action labels} [pos] {payoffs} [pos]
% second option is redundant (this helps not getting errors when playing with \istbA)
\NewDocumentCommand \istbt
{ s D(){1} D<>{} O{} +G{} O{} +g O{\istgrowdirection} }
{ 
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ #3 ] 
      { 
        \IfBooleanTF  { #1 } { \xt@ndot } { \xt@show@tndot }
        \IfValueT     { #7 } { \ist_payoff:nn { #8 } { #7 } }
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow , #4 } { #6 } { #5 } 
      }
    }
}


% \istB(*) % dual version
% * <grow,xtdistances> [line style] {AL 1} [pos 1] {AL 2} [pos 2] {payoffs} [pos]
\NewDocumentCommand \istB
{ s D<>{} O{} +G{} O{} +G{} O{} +g O{\istgrowdirection} }  
{ 
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ #2 ] 
      { 
        \IfBooleanTF  { #1 } { \xt@ndot } { \xt@show@endpoint }
        \IfValueT     { #8 } { \ist_payoff:nn { #9 } { #8 } }
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow } { #7 } { #6 } 
        \ist_move:nnn { #3 } { #5 } { #4 } 
      }
    }
}


% \istBt(*)  % dual terminal version
% * <grow,xt-distances> [line style] {AL 1} [pos 1] {AL 2} [pos 2] {payoffs} [pos]
\NewDocumentCommand \istBt
{ s D<>{} O{} +G{} O{} +G{} O{} +g O{\istgrowdirection} }  
{ 
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ #2 ] 
      { 
        \IfBooleanTF  { #1 } { \xt@ndot } { \xt@show@tndot }
        \IfValueT     { #8 } { \ist_payoff:nn { #9 } { #8 } }
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow } { #7 } { #6 } 
        \ist_move:nnn { #3 } { #5 } { #4 } 
      }
    }
}


% \istbA (arc version)  -- to work with \istrootcntmA and variants
% * (Xpoint adj factor) <grow,xt-distances> [line style] {action labels} [pos] {payoffs} [pos]
% code complication, inevitable to take care of too many cases
\NewDocumentCommand \istbA
{ s D(){1} D<>{} O{} +G{} O{} +g O{\istgrowdirection} }
{
    %% to toss adjusted levdist and sibdist for every case
    \bool_if:NTF \_istroot_cntmA_call_bool
    { % with \istrootcntmA
      % adjust levdist (to make longer branch only for \istrootcntmA and its oval version)
      \pgfmathsetmacro \xtlevdistVarA { \cntmApos * \_cntmA_levdist_local_tl * \cntmAplotfactorAdj } 
      \pgfmathsetmacro \xtsibdistVarA { \cntmApos * \_cntm_act_sibdist_local_tl } % better not mul \...Adj
      % this is correct            (there is no \_cntmA_act_sibdist_local_tl)
    }
    {
      \bool_if:NTF \_istroot_cntm_call_bool
      { % with \istrootcntm
        \pgfmathsetmacro \xtlevdistVarA { \cntmpos * \_cntm_levdist_local_tl }
        \pgfmathsetmacro \xtsibdistVarA { \cntmpos * \_cntm_act_sibdist_local_tl }
      }
      { 
        \bool_if:NTF \_xt_levdist_local_call_bool
        { % if +#8..#9+ exists ( \_xt_levdist_local_tl defined in \istroot )
          \pgfmathsetmacro \xtlevdistVarA { \_xt_levdist_local_tl }  
          \pgfmathsetmacro \xtsibdistVarA { \_xt_sibdist_local_tl }
        }
        { % ordinary case
          \pgfmathsetmacro \xtlevdistVarA { \xtlevdist } 
          \pgfmathsetmacro \xtsibdistVarA { \xtsibdist }
        }
      }
    }
    %% draw branch
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ level~distance = #2 * \xtlevdistVarA , sibling~distance = \xtsibdistVarA , #3 ] 
      { 
        \IfBooleanTF  { #1 } { \xt@ndot } { \xt@show@endpoint }
        \IfValueT     { #7 } { \ist_payoff:nn { #8 } { #7 } }
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow , #4 } { #6 } { #5 } 
      }
    }
}


% \istbAt (arc terminal version)
% * (Xpoint adj factor) <grow,xt-distances> [line style] {action labels} [pos] {payoffs} [pos]
\NewDocumentCommand \istbAt
{ s D(){1} D<>{} O{} +G{} O{} +g O{\istgrowdirection} }
{   
    %% to toss adjusted levdist and sibdist for every case
    \bool_if:NTF \_istroot_cntmA_call_bool
    { % with \istrootcntmA
      % adjust levdist (to make longer branch only for \istrootcntmA and its oval version)
      \pgfmathsetmacro \xtlevdistVarA { \cntmApos * \_cntmA_levdist_local_tl * \cntmAplotfactorAdj } 
      \pgfmathsetmacro \xtsibdistVarA { \cntmApos * \_cntm_act_sibdist_local_tl } % better not mul \...Adj
      % this is correct            (there is no \_cntmA_act_sibdist_local_tl)
    }
    {
      \bool_if:NTF \_istroot_cntm_call_bool
      { % with \istrootcntm
        \pgfmathsetmacro \xtlevdistVarA { \cntmpos * \_cntm_levdist_local_tl }
        \pgfmathsetmacro \xtsibdistVarA { \cntmpos * \_cntm_act_sibdist_local_tl }
      }
      { 
        \bool_if:NTF \_xt_levdist_local_call_bool
        { % if +#8..#9+ exists ( \_xt_levdist_local_tl defined in \istroot )
          \pgfmathsetmacro \xtlevdistVarA { \_xt_levdist_local_tl }  
          \pgfmathsetmacro \xtsibdistVarA { \_xt_sibdist_local_tl }
        }
        { % ordinary case
          \pgfmathsetmacro \xtlevdistVarA { \xtlevdist } 
          \pgfmathsetmacro \xtsibdistVarA { \xtsibdist }
        }
      }
    }
    %% draw branch
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ level~distance = #2 * \xtlevdistVarA , sibling~distance = \xtsibdistVarA , #3 ] 
      { 
        \IfBooleanTF  { #1 } { \xt@ndot } { \xt@show@tndot }
        \IfValueT     { #7 } { \ist_payoff:nn { #8 } { #7 } }
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow , #4 } { #6 } { #5 } 
      }
    }
}


% \printist  (to use \istrootcntm and all its variants)
\NewDocumentCommand \printist { }
{
    \tl_use:N \ischo_game_tl
}

% \endist
\NewDocumentCommand \endist { }
{
    % call set false for changing branch lengths with \istbA
    \bool_set_false:N \_istroot_cntm_call_bool
    \bool_set_false:N \_istroot_cntmA_call_bool
    % final print of simple tree
    \printist ;
    % restore initial values for \cntmistb and \cntmAistb
    \cntmistbVariablesRestore
    \cntmAistbVariablesRestore
}


%%% continuum of branches %%%


%% preset for continuum of branches (used in \ISTCntm, \ISTCntmArc)

%% cntm distances
\def\cntmdefaultlevdist{8mm}
%\def\cntmdefaultsibdist{3*\cntmdefaultlevdist}
\def\cntmdefaultsibdist{24mm}
\newcommand*\cntmlevdist{\cntmdefaultlevdist}
\pgfmathsetmacro\tmpcntmsibdist{3*\cntmlevdist} % this detour is safer
\newcommand*\cntmsibdist{\tmpcntmsibdist}

% cntm action sibling distance (used in \ISTCntm, \ISTCntmArc)
\def\cntm@default@actsibdist{\cntmsibdist/3}
\newcommand*\cntmACTsibdist{\cntm@default@actsibdist}
\NewDocumentCommand \cntmactsibdist{m}
{
    \renewcommand*\cntmACTsibdist{#1}
}

% \cntmdistance call test
\bool_new:N \cntm_distance_call_bool 
\bool_set_false:N \cntm_distance_call_bool
\bool_new:N \cntm_act_sibdist_call_bool 
\bool_set_false:N \cntm_act_sibdist_call_bool

% \cntmdistance
% use this BEFORE \istrootcntm and \istrootcntmA
% * {cntmlevdist} {cntmsibdist} {cntm act sibdist} [cntm color]
\NewDocumentCommand \cntmdistance
{ s m G{ \cntmdefaultsibdist } g }
{ 
    \IfBooleanT {#1}
    {
      \renewcommand*\xtlevdist { \cntmlevdist }
      \renewcommand*\xtsibdist { \cntmsibdist }
    }

    \renewcommand*\cntmlevdist {#2}
    \renewcommand*\cntmsibdist {#3}

    \IfValueTF {#4} 
    { % this call set is used in \istrootcntm and its variants
      % distinguish \cntmactsibdist from \cntmsibdist, the latter used only for cntm
      \bool_set_true:N \cntm_act_sibdist_call_bool 
      \cntmactsibdist {#4}
    }
    { 
      \cntmactsibdist { \cntm@default@actsibdist }
    }
    
    \bool_set_true:N \cntm_distance_call_bool
%    \tikzset{level~1/.style={level~distance=\cntmlevdist,sibling~distance=\cntmsibdist}}
}

%===========================================
%===========================================

%% information sets

% infoset layer (for every infoset)
\def\xtdefault@infosetlayer{background}
\newcommand*\xtinfosetlayer{\xtdefault@infosetlayer}
\NewDocumentCommand \setxtinfosetlayer{ G{ \xtdefault@infosetlayer } }
{
    \renewcommand*\xtinfosetlayer {#1}
}

% infoset style (for every infoset)
\def\xtdefault@infoset@style{}
\newcommand*\xtdefaultinfosetstyle{\xtdefault@infoset@style}

\NewDocumentCommand \setxtinfosetstyle { G{} }
{
    \tikzset { infoset~style/.style = { semithick, densely~dotted, #1 } }
}
% initial set (as infoset style = {semithick,densely dotted})
\setxtinfosetstyle

% infoset height (for oval type)
\def\xtdefault@infosetheight { 1em } % 1em=12pt
\newcommand*\xtinfosetheight { \xtdefault@infosetheight }


% \xtInfoset
% * [opt] (from) (to) {owner} [pos]
\NewDocumentCommand \xtInfoset { s O{} r() r() +G{} O{} }
{
    \begin{pgfonlayer}{\xtinfosetlayer}
    \draw [ - , infoset~style , #2 ] (#3) to (#4) ;
    \IfBooleanTF {#1} { } { \setistmathTF011 \istownertextfont{} } % must be in group
%    \str_case_e:nnF {#6}
    \str_case:nnF {#6}
    {
      {al} { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ above~left ]  { \istownerstyle{#5} } ; }
      {ar} { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ above~right ] { \istownerstyle{#5} } ; }
      {bl} { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ below~left ]  { \istownerstyle{#5} } ; }
      {br} { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ below~right ] { \istownerstyle{#5} } ; }
      {l}  { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ left ]        { \istownerstyle{#5} } ; }
      {r}  { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ right ]       { \istownerstyle{#5} } ; }
      {a}  { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ above ]       { \istownerstyle{#5} } ; }
      {b}  { \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ below ]       { \istownerstyle{#5} } ; }
    }
    {
             \node [-] at ( $ (#3) ! .5 ! (#4) $ ) 
                   [ above , #6 ]  { \istownerstyle{#5} } ;
    }
    \end{pgfonlayer}
}

% \xtInfosetO -- oval version

% * [opt] (from) (to) {owner} [pos] (height dim)
\NewDocumentCommand \xtInfosetO { s O{} r() r() +G{} O{} D(){\xtdefault@infosetheight} }
{
    \begin{scope} % in group: to make \setistmathT011 local
    \IfBooleanTF {#1} { } { \setistmathTF011 \istownertextfont{} }
    \coordinate (xtinfoA) at (#3) ;
    \coordinate (xtinfoB) at (#4) ;
    \renewcommand*\xtinfosetheight {#7}

    \istgameScaleCallTestAndAdjust % (must be in a GROUP) % this determines \xsinfosetheightvar 
    
%    \str_if_eq:eeTF { #3 } { #4 }
    \str_if_eq:nnTF { #3 } { #4 }
    {% singleton infoset with a circle
      \begin{pgfonlayer}{\xtinfosetlayer}
      \draw [ - ] (xtinfoA) node [ - , draw ,  circle , samples=500 , inner~sep = 0pt, 
            minimum~size = \xtinfosetheightvar , infoset~style , #2 ] {} ; % -var needed for scaling
      \end{pgfonlayer}
      \draw [ draw = none , - ] (#3) node [ - , #6 ] { \istownerstyle{#5} } ;      
    }
    {% connecting two nodes
      \renewcommand*\xtinfosetheight {#7}
      \begin{pgfonlayer}{\xtinfosetlayer}
        \path 
          let
          \p1 = ( $ (xtinfoA.center) - (xtinfoB.center) $ ) ,
          \n1 = { veclen(\x1,\y1) }
          in
          (xtinfoA) -- (xtinfoB)
          node [ - , draw , rectangle , samples = 500 , inner~sep = 0pt ,
                 transform~shape , sloped , midway ,
                 rounded~corners = .5*\xtinfosetheightvar , % var needed for scaling
                 minimum~width = \n1 + \xtinfosetheight , 
                 minimum~height = \xtinfosetheight , infoset~style , #2 ] { } ;
        \draw [ draw = none , - ] (xtinfoA) to 
              [ edge~node = { node [ - , #6 ] { \istownerstyle{#5} } } ] (xtinfoB) ; % (in group)
      \end{pgfonlayer}
    }
    \end{scope}
}


%===========================================

%% CI(curve infoset) defaults
\def\xtCI@default@opt {   }          % CI line option
\def\xtCI@default@pos { 1 }          % CI position
\def\xtCI@default@plotfactor { 1.3 } % CI curvature
\def\xtCInfosetplotfactor { \xtCI@default@plotfactor }
\newcommand*\xtCIopt { \xtCI@default@opt }  
\newcommand*\xtCIpos { \xtCI@default@pos }  
\newcommand*\xtCIplotfactor { \xtCI@default@plotfactor } 
\def\xtcimidvarfactor { .5 }

% base distance to CI-root and mid-point (used in \xtCInfosetO)
\def\xtCI@default@rootdist { 25mm }

% xtCI default positions (used in \xtCInfosetO)
\def\xtCIdefaultpos  { 0 }
\def\xtCIdefaultposA { -1 }
\def\xtCIdefaultposB { 1 }

% \setxtCIplotfactor
% use this before \istrootcntmA
\NewDocumentCommand \setxtCIplotfactor { m }
{
    \renewcommand*\xtCIplotfactor {#1}
    \edef\xtCInfosetplotfactor {#1}
} 

% detouring colon problem
\NewExpandableDocumentCommand \setxtCIAngleAccordingtoGrowswapCall { }
{
    \bool_if:NTF \xt_growswap_call_bool
    { \tl_set:Nn \xtCIang {  90 } } 
    { \tl_set:Nn \xtCIang { -90 } } 
}

% detouring colon problem
\def\xtciang@adjusted { 35 }
\def\xtciang@adjustedLessThanOne { -15 }

% #1 : \xtciplotfactor
% #2 : midvarfactor
\NewExpandableDocumentCommand \setxtCIAngleAccordingtoGrowswapCallForCI { m m }
{
  \bool_if:NTF \xt_growswap_call_bool
    { % growswap true
      \tl_set:Nn \xtCIangNew { 90 } 
      \tl_set:Nn \xtcisign { -1 }
      \pgfmathsetmacro \xtciangA {  45-45*(#1-1)/.6 } 
      \pgfmathsetmacro \xtciangB { -45+45*(#1-1)/.6 } 
      \tl_if_novalue:nF { #2 }  %% equivalent to \IfNoValueTF
      {
        \fp_compare:nTF { .5 > #2 }
        {
          \fp_compare:nTF { 1 > #1 }
          {
            \pgfmathsetmacro \xtciangA { \xtciangA + 60 - \xtciang@adjusted }
          }
          {
            \pgfmathsetmacro \xtciangA { \xtciangA - \xtciang@adjusted }
          }
        }
        {
          \fp_compare:nT { .5 < #2 }
          {
            \fp_compare:nTF { 1 > #1 }
            { 
              \pgfmathsetmacro \xtciangB { \xtciangB - 60 + \xtciang@adjusted }
            }
            { 
              \pgfmathsetmacro \xtciangB { \xtciangB + \xtciang@adjusted }
            }
          }
        }
      }
    } 
    { % growswap false (no problem)
      \tl_set:Nn \xtCIangNew { -90 } 
      \tl_set:Nn \xtcisign { 1 }
      \pgfmathsetmacro\xtciangA{ -45+45*(#1-1)/.6 }
      \pgfmathsetmacro\xtciangB{  45-45*(#1-1)/.6 }
      \fp_compare:nT { 1.0 > #1 } { \edef\xtciang@adjusted { \xtciang@adjustedLessThanOne } }
      \tl_if_novalue:nF { #2 }  %% equivalent to \IfNoValueTF
      {
        \fp_compare:nTF { .5 > #2 }
        {
          \pgfmathsetmacro \xtciangA { \xtciangA + \xtciang@adjusted } % if midvarfactor < .5
        }
        {
          \fp_compare:nT { .5 < #2 }
          {
            \pgfmathsetmacro \xtciangB { \xtciangB - \xtciang@adjusted } % if midvarfactor > .5
          }
        }
      }
    }
}


%% detouring colon problem
\def\ciang@adjusted { 35 }
\def\ciang@adjustedLessThanOne { -15 }

\let \cntminfosetheight \xtinfosetheight
% #1 : \ciplotfactor
\NewExpandableDocumentCommand \setciAngleAccordingtoGrowswapCallForCntmAI { m }
{
  \bool_if:NTF \xt_growswap_call_bool
    { % growswap true
      \tl_set:Nn \ciangNew { 90 } 
      \tl_set:Nn \cisign { -1 }
      \pgfmathsetmacro \ciangA { -45+45*(#1-1)/.9 }
      \pgfmathsetmacro \ciangB {  45-45*(#1-1)/.9 }
    } 
    { % growswap false
      \tl_set:Nn \ciangNew { -90 } 
      \tl_set:Nn \cisign { 1 }
      \pgfmathsetmacro \ciangA {  45-45*(#1-1)/.9 }
      \pgfmathsetmacro \ciangB { -45+45*(#1-1)/.9 }
    }
}

%% detouring abbreviations (used in \xtCInfoset)
\NewDocumentCommand \xtCInfosetAbbreviations { m }
{
%  \str_case_e:nnF {#1}
  \str_case:nnF {#1}
  {
    {l}  { \def\xtciowner@pos { left }        }
    {r}  { \def\xtciowner@pos { right}        }
    {a}  { \def\xtciowner@pos { above}        }
    {b}  { \def\xtciowner@pos { below}        }
    {al} { \def\xtciowner@pos { above~left }  }
    {ar} { \def\xtciowner@pos { above~right } }
    {bl} { \def\xtciowner@pos { below~left }  }
    {br} { \def\xtciowner@pos { below~right } }
  }
  {
    \def\xtciowner@pos {#1}
  }
  \tl_set:Nx \xtcioptionstring { at (xtC) [ above , \xtciowner@pos ] }
}

% detouring colon problem (for comparing two node being identical or not)
% \xtCITestCoordinates (used in \xtCInfoset)
\newif \ifxtCIsamecoordinates
\NewDocumentCommand \xtCITestCoordinates { m m }
{
%    \str_if_eq:eeTF {#1} {#2}
    \str_if_eq:nnTF {#1} {#2}
    {
      \xtCIsamecoordinatestrue
    }
    {
      \xtCIsamecoordinatesfalse
    }
}


%++++++++++++++++++++++++++++++++++++
%% +++ ONLY FOR DEVELOPER +++++++++++
%% to show X points and X circles (this is used in definition of \xtCInfosetO and \cntmAInfosetO)

% getting ready to show X points
\newif \ifxtXpoints
\newif \ifxtXpointsONE
\newif \ifxtXpointsTWO
\newif \ifxtXpointsTHREE
\newif \ifxtXpointsFOUR
\newif \ifxtXpointsLabel
% getting ready to show X circles
\newif \ifxtXcircles
\newif \ifxtXcircleX
\newif \ifxtXcircleY

% showing X circles
% used in \xtshowXpoints
% can be used independently
\NewDocumentCommand \xtshowXcircles { m }
{
    \xtXcircleXfalse
    \xtXcircleYfalse
    \xtXcirclestrue
    \int_compare:nTF { #1 >= 3 }
    {
      \xtXcircleXtrue
      \xtXcircleYtrue
    }
    {
      \int_compare:nTF { #1 >= 2 }
      {
        \xtXcircleXfalse
        \xtXcircleYtrue
      }
      {
        \int_compare:nT { #1 >= 1 }
        {
          \xtXcircleXtrue
          \xtXcircleYfalse
        }
      }
    }
}

% hide X circles
\NewDocumentCommand \xthideXcircles { }
{
  \xtXcirclesfalse
}

% to control point size
\def\xtXpoint@sizeA { \istsolidnodesize }
\def\xtXpoint@sizeB { 5/3 * \istsolidnodesize }
\newcommand*\xtXpointsizeA { \xtXpoint@sizeA }
\newcommand*\xtXpointsizeB { \xtXpoint@sizeB }

% showing X points
% \xtshowXpoints
% * {point choice num}{circle choice num}(points size dim)(basic points size dim)
% usage: \xtshowXpoints33(2pt)(3pt)
% point choice number: 0,1,2,3,4
% circle choice number: 0,1,2,3
% this serves \xtCInfosetO as well as \cntmAInfosetO
\NewDocumentCommand \xtshowXpoints { s m m D(){\xtXpoint@sizeA} D(){\xtXpoint@sizeB} }
{
    \renewcommand*\xtXpointsizeA {#4}
    \renewcommand\xtXpointsizeB {#5}
    \xtXpointsLabelfalse
    \IfBooleanTF {#1} { \xtXpointsLabeltrue } { \xtXpointsLabelfalse }
    \xtXpointsONEfalse
    \xtXpointsTWOfalse
    \xtXpointsTHREEfalse
    \xtXpointsFOURfalse
    \xtXpointstrue 
    \int_compare:nTF { #2 >= 4 }
    {
        \xtXpointsTHREEtrue
        \xtXpointsTWOtrue
        \xtXpointsONEtrue
    }
    {
      \int_compare:nTF { #2 >= 3 }
      {
          \xtXpointsONEfalse
          \xtXpointsTWOtrue
          \xtXpointsTHREEtrue
      }
      {
        \int_compare:nTF { #2 >= 2 }
        {
          \xtXpointsONEtrue
          \xtXpointsTWOtrue
          \xtXpointsTHREEfalse
        }
        {
          \int_compare:nT { #2 >= 1 }
          {
          \xtXpointsONEtrue
          \xtXpointsTWOfalse
          \xtXpointsTHREEfalse
          }
        }
      }
    }
    \xtshowXcircles{#3}
}

% hide X points
\NewDocumentCommand \xthideXpoints {}
{
    \xtXpointsfalse
}
%++++++++++++++++++++++++++++++++++++


\ExplSyntaxOff

%%-----------------
%% expl3 up to here (paused, because of colon problem)
%%-----------------

%---syntaxoff-----
% \xtCInfoset
% * [line opt] (beg-coor) !offmid weight! (end-coor) <plotfactor> +G{} O{} (info height dim)
\NewDocumentCommand \xtCInfoset
{ s O{} r() d!! r() D<>{\xtCIplotfactor} +G{} O{} }
{
\begin{scope}
\istgameScaleCallTestAndAdjust % (must be in a GROUP)
    \IfBooleanTF {#1} { } { \setistmathTF011 \istownertextfont{} } % must be in a group
    
    \coordinate (xtA) at (#3) ;
    \coordinate (xtB) at (#5) ;
    \edef\xtciplotfactor {#6}
    \def\xtcitension { 1 }

    \IfValueT {#4} { \edef\xtcimidvarfactor {#4} }
    \setxtCIAngleAccordingtoGrowswapCallForCI {#6} {#4}
    
    \path
      let \p1 = ($(xtA)-(xtB)$) , \n1 = { veclen(\p1) }
      in  \pgfextra{ \xdef\xtcidist {\n1} } ;
    
    \coordinate (xtcimid) at ( $ (xtA) ! .5 ! (xtB) $ ) ;
    \coordinate (xtciroot) at ( $ (xtcimid) ! .5 * \xtcidist ! \xtCIangNew:(xtB) $ ) ;
    \coordinate (xtcimid-var) at ( $ (xtA) ! \xtcimidvarfactor ! (xtB) $ ) ;
    \coordinate (xtC) at ( $ (xtciroot) ! \xtciplotfactor ! (xtcimid-var) $ ) ;

    \begin{pgfonlayer}{\xtinfosetlayer}
    \draw [ - , samples=500 , tension = \xtcitension , infoset style , #2 ]
          plot [ smooth ] coordinates { (xtA) (xtC) (xtB) } ;
    % detoured abbreviations (\node at (xtC) [ above , #8 ] { \istownerstyle{#7} } ;)
    \xtCInfosetAbbreviations {#8}
    \expandafter \node \xtcioptionstring [-] { \istownerstyle{#7} };
    \end{pgfonlayer}
\end{scope}
}

%++++++++++++++++++++++++++++++++++++
%% +++ ONLY FOR DEVELOPER +++++++++++
%---syntaxoff-----
% for controlling X points
\tikzset { nodedot/.style = 
           { - , draw , fill , circle , inner sep = 0pt , minimum size = 2pt }
         }

%---syntaxoff-----
% * [node opt] (coor) <pos> {label} (min size dim)
\NewDocumentCommand \xtXnodedot { s O{} r() D<>{above} G{} D(){\istsolidnodesize} }
{
    \IfBooleanTF {#1}
    {
      \node at (#3) [ nodedot , minimum size = #6 ,
                      label={[label distance=-2pt]#4:{\tiny\ttfamily #5}} , #2 ] {} ;
    }
    {
      \node at (#3) [ nodedot , minimum size = #6 , #2 ] {} ;
    }
}
%++++++++++++++++++++++++++++++++++++

%---syntaxoff-----
% initial values
\def\xtcibegang {0}
\def\xtciendang {0}

\NewDocumentCommand \xtCInfosetOTurnX { m g }
{
    \renewcommand*\xtcibegang{#1}
    \IfNoValueTF {#2} 
      { \renewcommand*\xtciendang{-\xtcibegang} } 
      { \renewcommand*\xtciendang{#2} }
}

%---syntaxoff-----
% \xtCInfosetO
% * [line opt] (beg-coor) !offmid weight! (end-coor) <plotfactor> +G{} O{} (info height dim)
\NewDocumentCommand \xtCInfosetO
{ s O{} r() d!! r() D<>{\xtCIplotfactor} +G{} O{} D(){\xtdefault@infosetheight} }
{
    \begin{scope}
    \IfBooleanTF {#1} { } { \setistmathTF011 \istownertextfont{} } % must be in a group
    
    \coordinate (xtA) at (#3) ;
    \coordinate (xtB) at (#5) ;
    \renewcommand*\xtinfosetheight{#9}

    \istgameScaleCallTestAndAdjust % (must be in a GROUP)   % this determines \xsinfosetheightvar 
    \xtCITestCoordinates{#3}{#5}
    \ifxtCIsamecoordinates 
      \begin{pgfonlayer}{\xtinfosetlayer}
      \draw [ - ] (xtA) 
            node [ - , draw , circle , samples = 500 , inner sep = 0pt , 
                   minimum size=\xtinfosetheightvar , % var needed for scaling
                   infoset style , #2 
                 ] { } ; 
      \end{pgfonlayer}
      \node at (#3) [ - , #8 ] { \istownerstyle{#7} } ;
    \else
      \edef\xtciplotfactor{#6}
      \def\xtcitension{1}
      \def\xradius{ .5*\xtinfosetheight }
      \xdef\tosstoxtXcircles{\xtinfosetheightvar}           % +++ for developer (see below) +++
  
      \IfValueT {#4} {\edef\xtcimidvarfactor{#4}}
      \setxtCIAngleAccordingtoGrowswapCallForCI{#6}{#4}
      
      \path
        let \p1 = ($(xtA)-(xtB)$) , \n1 = {veclen(\p1)}
        in  \pgfextra{\xdef\xtcidist{\n1}} ;
  
      \pgfmathsetmacro\xratio{ scalar(\xtCI@default@rootdist/\xtcidist) }
      
      \coordinate (xtcimid) at ($(xtA)!.5!(xtB)$) ;
      \coordinate (xtciroot) at ($(xtcimid)!.5*\xtcidist!\xtCIangNew:(xtB)$) ;
      \coordinate (xtcimid-var) at ($(xtA)!\xtcimidvarfactor!(xtB)$) ;
      \coordinate (xtC) at ($(xtciroot)!\xtciplotfactor!(xtcimid-var)$) ;
  
      \path (xtciroot) -- (xtA) -- 
            ( [turn] \xtciangA+\xtcibegang:\xradius) coordinate (xtAA1) ; 
      \path (xtciroot) -- (xtB) -- 
            ( [turn] \xtciangB+\xtciendang:\xradius) coordinate (xtBB1) ; 
  
      \coordinate (xtAA2) at ($(xtAA1)!2!(xtA)$) ;
      \coordinate (xtBB2) at ($(xtBB1)!2!(xtB)$) ;
  
      \draw [ draw=none , - ] (xtciroot) -- (xtC) -- ([turn]0:\xradius) coordinate (xtCC1) ;
      \draw [ draw=none , - ] (xtciroot) -- (xtC) -- ([turn]180:\xradius) coordinate (xtCC2) ;
      
      \coordinate (XpointA) at ($(xtA)!\xradius!-\xtCIangNew:(xtAA1)$) ;
      \coordinate (XpointB) at ($(xtB)!\xradius! \xtCIangNew:(xtBB1)$) ;
  
      \begin{pgfonlayer}{\xtinfosetlayer}
      \draw [ - , samples = 500 , tension = \xtcitension , infoset style , #2 ]
            plot [smooth] 
                 coordinates {(xtAA1)(xtCC1)(xtBB1)} --
            plot [smooth,tension=1.75] 
                 coordinates {(xtBB1)(XpointB)(xtBB2)} --
            plot [smooth] 
                 coordinates {(xtBB2)(xtCC2)(xtAA2)} --
            plot [smooth,tension=1.75] 
                 coordinates {(xtAA2)(XpointA)(xtAA1)} -- cycle ;
      \node at (xtC) [ - , #8 ] { \istownerstyle{#7} } ;
      \end{pgfonlayer}
    \fi
    \end{scope}
    % back to initial values
    \def\xtcibegang{0}
    \def\xtciendang{0}
    %++++++++++++++++++++++++++++++++++++
    %% +++ ONLY FOR DEVELOPER +++++++++++
    %% control points
    \ifxtXpoints
      \ifxtXpointsONE
        \ifxtXpointsLabel
          \xtXnodedot*[fill=green](xtA)<right>{A}(\xtXpointsizeB)
          \xtXnodedot*[fill=green](xtB)<left>{B}(\xtXpointsizeB)
          \xtXnodedot*[green](xtC)<right>{C}(\xtXpointsizeB)
          \xtXnodedot*[fill=blue!40](xtciroot)<right>{root}(\xtXpointsizeB)
          \xtXnodedot*[fill=green](xtcimid-var)<right>{m}(\xtXpointsizeB)
        \else
          \xtXnodedot[fill=green](xtA)<right>{A}(\xtXpointsizeB)
          \xtXnodedot[fill=green](xtB)<left>{B}(\xtXpointsizeB)
          \xtXnodedot[green](xtC)<right>{C}(\xtXpointsizeB)
          \xtXnodedot[fill=blue!40](xtciroot)<right>{root}(\xtXpointsizeB)
          \xtXnodedot[fill=green](xtcimid-var)<right>{m}(\xtXpointsizeB)
        \fi
      \fi
      \ifxtXpointsTWO
        \ifxtXpointsLabel
          \xtXnodedot*[blue](xtAA1){a1}(\xtXpointsizeA)
          \xtXnodedot*[red](xtAA2)<below>{a2}(\xtXpointsizeA)
          \xtXnodedot*[blue](xtBB1){b1}
          \xtXnodedot*[red](xtBB2)<below>{b2}(\xtXpointsizeA)
          \xtXnodedot*[blue](xtCC1){c1}(\xtXpointsizeA)
          \xtXnodedot*[red](xtCC2)<below>{c2}(\xtXpointsizeA)
        \else
          \xtXnodedot[blue](xtAA1){a1}(\xtXpointsizeA)
          \xtXnodedot[red](xtAA2)<below>{a2}(\xtXpointsizeA)
          \xtXnodedot[blue](xtBB1){b1}(\xtXpointsizeA)
          \xtXnodedot[red](xtBB2)<below>{b2}(\xtXpointsizeA)
          \xtXnodedot[blue](xtCC1){c1}(\xtXpointsizeA)
          \xtXnodedot[red](xtCC2)<below>{c2}(\xtXpointsizeA)
        \fi
      \fi
      \ifxtXpointsTHREE
        \ifxtXpointsLabel
          \xtXnodedot*[blue](XpointA)<left>{x}(\xtXpointsizeA)
          \xtXnodedot*[red](XpointB)<right>{y}(\xtXpointsizeA)
        \else
          \xtXnodedot[blue](XpointA)<left>{x}(\xtXpointsizeA)
          \xtXnodedot[red](XpointB)<right>{y}(\xtXpointsizeA)
        \fi
      \fi
    \fi
    % X circles
    \ifxtXcircles
      \ifxtXcircleX
        \node at (xtA) [ - , circle , draw=blue , opacity=.5 , 
                         minimum size=\tosstoxtXcircles ] {} ;
      \fi
      \ifxtXcircleY
        \node at (xtB) [ - , circle , draw=red , opacity=.5 , 
                         minimum size=\tosstoxtXcircles ] {} ;
      \fi
    \fi
    %++++++++++++++++++++++++++++++++++++
}


%% continuum of branches : information sets

%---syntaxoff-----
%% cntmA defaults (used in \ISTCntmArc)
\def\cntmA@default@opt {}   % arc line option
\def\cntmA@default@pos {1} % arc position %% default was .5
\def\cntmA@default@plotfactor {1.333} % arc curvature
\def\cntmAInfosetplotfactor {\cntmA@default@plotfactor}
\def\cntmA@default@fillcolor {transparent} % no white
\newcommand*\cntmAopt {\cntmA@default@opt}  
\newcommand*\cntmApos {\cntmA@default@pos}  
\newcommand*\cntmAplotfactor {\cntmA@default@plotfactor} 
\newcommand*\cntmAfillcolor  {\cntmA@default@fillcolor}

%---syntaxoff-----
% \cntmAplotfactorset
% use this before \istrootcntmA
\NewDocumentCommand \cntmAplotfactorset { m }
{
    \renewcommand*\cntmAplotfactor {#1}
    \edef\cntmAInfosetplotfactor {#1}
} 

%---syntaxoff-----
% \cntmApreset
% use this before \istrootcntmA
% \cntmApreset
% [Aopt]<plotfactor>{Apos}[fill color]
% use fill color only at the second bracket option (not first)
\NewDocumentCommand \cntmApreset
{ O{\cntmA@default@opt} D<>{\cntmA@default@plotfactor} g O{\cntmA@default@fillcolor} }
{
    \IfNoValueTF {#3}
    {
      \renewcommand*\cntmApos {\cntmA@default@pos}
    }
    {
      \renewcommand*\cntmApos {#3}
    }
    \renewcommand*\cntmAopt {#1}
    \cntmAplotfactorset {#2}
    \renewcommand*\cntmAfillcolor {#4}
}


%---syntaxoff-----
% cntm layer
\def\cntm@default@layer{background} % better than behind
\NewDocumentCommand \cntmlayerset{ m }
{
    \renewcommand*\cntm@default@layer{#1}
}

%---syntaxoff-----
% cntmA layer
\def\cntmA@default@layer{behind} % better than background
\newcommand*\cntmAdefaultlayer{\cntmA@default@layer}
\NewDocumentCommand \cntmAlayerpreset{ G{\cntmA@default@layer} }
{
    \renewcommand*\cntmAdefaultlayer{#1}
}


%---syntaxoff-----
% \cntmAInfoset
% [Aopt] (cntm-root) <\xtCIplotfactor> {addto cntmApos} 
\NewDocumentCommand \cntmAInfoset
{ O{\cntmA@default@opt} r() D<>{\cntmAInfosetplotfactor} G{.1} } 
{
    % save arc options and position
    \let\tmpAIpos\cntmApos
    \let\tmpAIopt\cntmAopt
    \pgfmathsetmacro{\cntmAInfosetpos}{\cntmApos+#4}
  
    \coordinate (ciroot) at (#2) ;
    \coordinate (ciA) at ($(ciroot)!\cntmAInfosetpos!(cntm-1)$) ;
    \coordinate (ciB) at ($(ciroot)!\cntmAInfosetpos!(cntm-2)$) ;
    \edef\ciplotfactor{#3}
    \def\citension{1}
    
    \pgfmathsetmacro\cidistratio{ scalar(\cntmlevdist/\cntmsibdist) }
    \pgfmathsetmacro\ciplotfactorVal{ 1 + (\ciplotfactor-1) * sqrt(1/3) / sqrt(\cidistratio) }
    
    \coordinate (cimid) at ($(ciA)!.5!(ciB)$) ;
    \coordinate (ciC) at ($(ciroot)!\ciplotfactorVal!(cimid)$) ;
    
    \begin{pgfonlayer}{\xtinfosetlayer}
    \draw [ - , samples=500 , tension = \citension , infoset style , #1 ]
          plot [smooth] coordinates {(ciA)(ciC)(ciB)} ;
    \end{pgfonlayer}
    \let\cntmApos\tmpAIpos
    \let\cntmAopt\tmpAIopt
}


%---syntaxoff-----
% \cntmAInfosetO
% [Aopt] (cntm-root) <plot factor> {Apos} [turn X-ang] (infoset height)
\NewDocumentCommand \cntmAInfosetO
{ O{\cntmA@default@opt} r() D<>{\cntmAInfosetplotfactor} G{\cntmApos} O{0} D(){\xtdefault@infosetheight} }
{
    \begin{scope}   
    \coordinate (ciroot) at (#2) ;
    \coordinate (ciA) at ($(ciroot)!#4!(cntm-1)$) ;
    \coordinate (ciB) at ($(ciroot)!#4!(cntm-2)$) ;
    \edef\ciplotfactor{#3}
    \def\ciAdjXang{#5}
    \def\cntminfosetheight{#6}
    \def\citension{1}

    \istgameScaleCallTestAndAdjust % (must be in a GROUP)
    \def\ciradius{ .5*\cntminfosetheight } % not -var
    \xdef\tosstocntmXcircles{\cntminfosetheightvar} % +++ for developer (see below) +++
    \setciAngleAccordingtoGrowswapCallForCntmAI{#3}
    
    \pgfmathsetmacro\cidistratio{ scalar(\cntmlevdist/\cntmsibdist) }
    % to ease the curvature (using \cidistratio)
    \pgfmathsetmacro\ciplotfactorVal{ 1 + (\ciplotfactor-1)*sqrt(1/3)/sqrt(\cidistratio) }
    % adjust Xangle
    \ifdim .5pt <\cidistratio pt
      \pgfmathsetmacro\ciDefaultAdjXang{  -5 + 30*\cidistratio }  % (10 if ratio=1/2 )
    \else
      \pgfmathsetmacro\ciDefaultAdjXang{ -10 + 30*\cidistratio } % (0 if ratio=1/3 )    
    \fi
    \pgfmathsetmacro\ciXadj{ \cisign * (\ciDefaultAdjXang - \ciAdjXang) }

    % defining coordinates
    \coordinate (cimid) at ($(ciA)!.5!(ciB)$) ;
    \coordinate (ciC) at ($(ciroot)!\ciplotfactorVal!(cimid)$) ;

    \path (ciroot) -- (ciA) -- 
          ( [turn] \ciangA-\ciXadj:\ciradius) coordinate (ciAA1) ;
    \path (ciroot) -- (ciB) -- 
          ( [turn] \ciangB+\ciXadj:\ciradius) coordinate (ciBB1) ;

    \coordinate (ciAA2) at ($(ciAA1)!2!(ciA)$) ;
    \coordinate (ciBB2) at ($(ciBB1)!2!(ciB)$) ;

    \draw [ draw=none , - ] 
          (ciroot) -- (ciC) -- ([turn]0:\ciradius) coordinate (ciCC1) ;
    \draw [ draw=none , - ] 
          (ciroot) -- (ciC) -- ([turn]180:\ciradius) coordinate (ciCC2) ;
    
    \coordinate (ciXpointA) at ($(ciA)!\ciradius! \ciangNew:(ciAA1)$) ;
    \coordinate (ciXpointB) at ($(ciB)!\ciradius!-\ciangNew:(ciBB1)$) ;

    \begin{pgfonlayer}{\xtinfosetlayer}
    \draw [ - , samples=500 , tension = \citension , infoset style , #1 ]
          plot [smooth] 
               coordinates {(ciAA1)(ciCC1)(ciBB1)} --
          plot [smooth,tension=1.75] 
               coordinates {(ciBB1)(ciXpointB)(ciBB2)} --
          plot [smooth] 
               coordinates {(ciBB2)(ciCC2)(ciAA2)} --
          plot [smooth,tension=1.75] 
               coordinates {(ciAA2)(ciXpointA)(ciAA1)} -- cycle ;
    \end{pgfonlayer}
    \end{scope}
    %++++++++++++++++++++++++++++++++++++
    %% +++ ONLY FOR DEVELOPER +++++++++++
    %% control points
    \ifxtXpoints
      \ifxtXpointsONE
        \ifxtXpointsLabel
          \xtXnodedot*[fill=green](ciA)<right>{A}(\xtXpointsizeB)
          \xtXnodedot*[fill=green](ciB)<left>{B}(\xtXpointsizeB)
          \xtXnodedot*[green](ciC)<right>{A}(\xtXpointsizeB)
          \xtXnodedot*[fill=green](ciroot)(\xtXpointsizeB)
          \xtXnodedot*[fill=green](cimid)<right>{m}(\xtXpointsizeB)
        \else
          \xtXnodedot[fill=green](ciA)<right>{A}(\xtXpointsizeB)
          \xtXnodedot[fill=green](ciB)<left>{B}(\xtXpointsizeB)
          \xtXnodedot[green](ciC)<right>{A}(\xtXpointsizeB)
          \xtXnodedot[fill=green](ciroot)(\xtXpointsizeB)
          \xtXnodedot[fill=green](cimid)<right>{m}(\xtXpointsizeB)
        \fi
      \fi
      \ifxtXpointsTWO
        \ifxtXpointsLabel
          \xtXnodedot*[blue](ciAA1)<below>{a1}(\xtXpointsizeA)
          \xtXnodedot*[red](ciAA2)<above>{a2}(\xtXpointsizeA)
          \xtXnodedot*[blue](ciBB1)<below>{b1}(\xtXpointsizeA)
          \xtXnodedot*[red](ciBB2)<above>{b2}(\xtXpointsizeA)
          \xtXnodedot*[blue](ciCC1)<below>{c1}(\xtXpointsizeA)
          \xtXnodedot*[red](ciCC2)<above>{c2}(\xtXpointsizeA)
        \else  
          \xtXnodedot[blue](ciAA1)<below>{a1}(\xtXpointsizeA)
          \xtXnodedot[red](ciAA2)<above>{a2}(\xtXpointsizeA)
          \xtXnodedot[blue](ciBB1)<below>{b1}(\xtXpointsizeA)
          \xtXnodedot[red](ciBB2)<above>{b2}(\xtXpointsizeA)
          \xtXnodedot[blue](ciCC1)<below>{c1}(\xtXpointsizeA)
          \xtXnodedot[red](ciCC2)<above>{c2}(\xtXpointsizeA)
        \fi
      \fi
      \ifxtXpointsTHREE
        \ifxtXpointsLabel
          \xtXnodedot*[blue](ciXpointA)<left>{x}(\xtXpointsizeA)
          \xtXnodedot*[red](ciXpointB)<right>{y}(\xtXpointsizeA)
        \else
          \xtXnodedot[blue](ciXpointA)<left>{x}(\xtXpointsizeA)
          \xtXnodedot[red](ciXpointB)<right>{y}(\xtXpointsizeA)
        \fi
      \fi
    \fi
    % X circles
    \ifxtXcircles
      \ifxtXcircleX
        \node at (ciA) [ - , circle , draw=blue , opacity=.5,
                         minimum size=\tosstocntmXcircles ] {} ;
      \fi
      \ifxtXcircleY
        \node at (ciB) [ - , circle , draw=red , opacity=.5 , 
                         minimum size=\tosstocntmXcircles ] {} ;
      \fi
    \fi
    %++++++++++++++++++++++++++++++++++++
}


%%-----------------
%% expl3 from here again
%%-----------------

\ExplSyntaxOn

%% preset for \istb (for outermost branches) for "cntm triangle" and "cntm arc"
% cntmA stands for "cntm arc"

% cntm color

\def\cntm@default@opt { }
\newcommand*\cntmopt  { \cntm@default@opt }

\def\cntm@default@drawcolor { black!25 }
\newcommand*\cntmdrawcolor  { \cntm@default@drawcolor }
\def\cntm@default@fillcolor { \cntm@default@drawcolor }
\newcommand*\cntmfillcolor  { \cntm@default@fillcolor }
\def\cntm@default@pos { 1 }
\newcommand*\cntmpos  { \cntm@default@pos }

% cntm outermost draw options
\def\cntm@default@branchopt { draw = none } % "draw=none" needed to keep cntm "triangle" default
\newcommand*\cntmbranchopt { \cntm@default@branchopt }

\def\cntmLeftAL     { } % leftmost AL
\def\cntmLeftALpos  { } % leftmost AL position
\def\cntmRightAL    { } % rightmost AL
\def\cntmRightALpos { } % rightmost AL position

% cntmA outermost draw options
\def\cntmAbranchdrawopt { } % "empty" needed for cntmA outermost "branch" control

\def\cntmALeftAL     { } % leftmost AL
\def\cntmALeftALpos  { } % leftmost AL position
\def\cntmARightAL    { } % rightmost AL
\def\cntmARightALpos { } % rightmost AL position


\bool_set_false:N \_cntm_pos_call_bool

% \cntmpreset
% * [ draw, color, fill ] { shrink factor } [ fill color ]
% the first, if exists, [ fill=color ] wins the second [ fill color ]
% that is, \cntmopt (with fill=color) wins \cntmfillcolor
\NewDocumentCommand \cntmpreset { s O{} g o }
{
    \IfNoValueTF {#3}
    {
      \renewcommand*\cntmpos{\cntm@default@pos}
    }
    {
      \renewcommand*\cntmpos{#3}
      \bool_set_true:N \_cntm_pos_call_bool
    }
    \IfBooleanTF {#1}
    {
      \IfValueTF {#4}
      {
        \renewcommand*\cntmfillcolor{#4}
        \renewcommand*\cntmopt{ - , solid , draw = black , fill = \cntmfillcolor , #2 }
      }
      {
        \renewcommand*\cntmopt{ - , solid , draw = black , fill = none , #2 }
      }
    }
    {
      \IfValueT {#4}
      {
        \renewcommand*\cntmdrawcolor{#4}
        \let\cntmfillcolor\cntmdrawcolor
      }
      \renewcommand*\cntmopt{ - , solid, draw = \cntmdrawcolor , fill = \cntmfillcolor, #2}
    }
}


% ============
% complication needed to resolve tex expansion issues
% ------------

% \cntmistb
% complication:
  % controls options for outermost branches via \l_cntm_left/rightmost_branch_opt_tl
  % finally used in \istrootcntm and \istrootocntm
% USE this BEFORE \istrootcntm
% * [ line opt ] { LEFT AL } [ LEFT pos ] { RIGHT AL } [ RIGHT pos ]
\NewDocumentCommand \cntmistb{ s O{} +G{} O{} +G{} O{} }
{
    % to resolve the nullfont problem (ndh)
    \tl_set_eq:NN \l_nullfont_tl \cntm@show@endpoint

    \renewcommand*\cntmbranchopt { - , draw=none, #2 }
    \renewcommand*\cntmLeftAL    {#3}
    \renewcommand*\cntmRightAL   {#5}
    \renewcommand*\cntmLeftALpos
    {
%      \str_case_e:nnF {#4}
      \str_case:nnF {#4}
      {
        {al} { above~left ,  text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift = -\istactionlabelyshift }
        {ar} { above~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift = -\istactionlabelyshift }
        {bl} { below~left ,  text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift =  \istactionlabelyshift }
        {br} { below~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift =  \istactionlabelyshift }
        {l}  { left ,  text~depth = .25ex , xshift = -\xtALxShift }
        {r}  { right , text~depth = .25ex , xshift =  \xtALxShift }
        {a}  { above , text~depth = .25ex , xshift =  \xtALxShift }
        {b}  { below , text~depth = .25ex , xshift = -\xtALxShift }
      }
      {
        #4
      }
    }
    \renewcommand*\cntmRightALpos
    {
%      \str_case_e:nnF {#6}
      \str_case:nnF {#6}
      {
        {al} { above~left  , text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift = -\istactionlabelyshift }
        {ar} { above~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift = -\istactionlabelyshift }
        {bl} { below~left  , text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift =  \istactionlabelyshift }
        {br} { below~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift =  \istactionlabelyshift }
        {l}  { left ,  text~depth = .25ex , xshift = -\xtALxShift }
        {r}  { right , text~depth = .25ex , xshift =  \xtALxShift }
        {a}  { above , text~depth = .25ex , xshift =  \xtALxShift }
        {b}  { below , text~depth = .25ex , xshift = -\xtALxShift }
      }
      {
        #6
      }
    }
    \IfBooleanTF {#1}
    { % disobey \xtShowEndPoints* -- force to print solid node
      \renewcommand*\cntm@show@endpoint { node [ at~end , solid~node ] {} }
    }
    { % obey \xtShowEndPoints* and toss the value to \istrootcntm(A) via \cntmOUTERistb
	    \tl_set:NV \cntm@show@endpoint \l_nullfont_tl  % (ndh)
    }
}


% \cntmAistb
% complication:
  % controls options for outermost branches via \l_cntmA_left/rightmost_branch_opt_tl
  % finally used in \istrootcntmA and \istrootocntmA
% USE this BEFORE \istrootcntmA
% * [ line opt ] { LEFT AL } [ LEFT pos ] { RIGHT AL } [ RIGHT pos ]
\NewDocumentCommand \cntmAistb { s O{-} +G{} O{} +G{} O{} }
{    
    % to resolve the nullfont problem (ndh)
    \tl_set_eq:NN \l_nullfont_tl \cntm@show@endpoint

    \renewcommand*\cntmAbranchdrawopt {#2}
    \renewcommand*\cntmALeftAL        {#3}
    \renewcommand*\cntmARightAL       {#5}
    \renewcommand*\cntmALeftALpos
    {
%      \str_case_e:nnF {#4}
      \str_case:nnF {#4}
      {
        {al} { above~left  , text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift = -\istactionlabelyshift }
        {ar} { above~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift = -\istactionlabelyshift }
        {bl} { below~left  , text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift =  \istactionlabelyshift }
        {br} { below~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift =  \istactionlabelyshift }
        {l}  { left ,  text~depth = .25ex , xshift = -\xtALxShift }
        {r}  { right , text~depth = .25ex , xshift =  \xtALxShift }
        {a}  { above , text~depth = .25ex , xshift =  \xtALxShift }
        {b}  { below , text~depth = .25ex , xshift = -\xtALxShift }
      }
      {
        #4
      }
    }
    \renewcommand*\cntmARightALpos
    {
%      \str_case_e:nnF {#6}
      \str_case:nnF {#6}
      {
        {al} { above~left  , text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift = -\istactionlabelyshift }
        {ar} { above~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift = -\istactionlabelyshift }
        {bl} { below~left  , text~depth = .25ex ,
               xshift =  \istactionlabelxshift , yshift =  \istactionlabelyshift }
        {br} { below~right , text~depth = .25ex ,
               xshift = -\istactionlabelxshift , yshift =  \istactionlabelyshift }
        {l}  { left ,  text~depth = .25ex , xshift = -\xtALxShift }
        {r}  { right , text~depth = .25ex , xshift =  \xtALxShift }
        {a}  { above , text~depth = .25ex , xshift =  \xtALxShift }
        {b}  { below , text~depth = .25ex , xshift = -\xtALxShift }
      }
      {
        #6
      }
    }
    \IfBooleanTF {#1}
    { % disobey \xtShowEndPoints* -- force to print solid node
      \renewcommand*\cntm@show@endpoint { node [ at~end , solid~node ] {} }
    }
    { % obey \xtShowEndPoints* and toss the value to \istrootcntm(A) via \cntmOUTERistb
	    \tl_set:NV \cntm@show@endpoint \l_nullfont_tl  % (ndh)
    }
}

% to restore initial values after \cntmistb
% (restore is done by \endist)
\def\cntmistbVariablesRestore
{
    \renewcommand*\cntmbranchopt  { \cntm@default@branchopt }
    \renewcommand*\cntmLeftAL     { }
    \renewcommand*\cntmRightAL    { }
    \renewcommand*\cntmLeftALpos  { }
    \renewcommand*\cntmRightALpos { }
}

% to restore initial values after \cntmistb
% (restore is done by \endist)
\def\cntmAistbVariablesRestore
{
    \renewcommand*\cntmAbranchdrawopt { }
    \renewcommand*\cntmALeftAL        { }
    \renewcommand*\cntmARightAL       { }
    \renewcommand*\cntmALeftALpos     { }
    \renewcommand*\cntmARightALpos    { }
}

% \cntmistb LEFT/RIGHT options:
% (still in the complication) collecting branch options input by \cntmistb
% the collected token list will be used in \istrootcntm and \istrootocntm
% [ - , \cntmAbranchdrawopt ] { LEFT AL } [ LEFT pos ] { RIGHT AL } [ RIGHT pos ]
\cs_new:Npn \_collect_cntm_leftmost_branch_opts:
{
    \tl_set:Nn \l_cntm_leftmost_branch_opt_tl       { [ - , }
    \tl_put_right:Nx \l_cntm_leftmost_branch_opt_tl { \cntmbranchopt ] }
    \tl_put_right:Nn \l_cntm_leftmost_branch_opt_tl { { \istactionlabelstyle { \cntmLeftAL } } }
    \tl_put_right:Nx \l_cntm_leftmost_branch_opt_tl { [ \cntmLeftALpos ] }
}

\cs_new:Npn \_collect_cntm_rightmost_branch_opts:
{
    \tl_set:Nn \l_cntm_rightmost_branch_opt_tl { [ - , }
    \tl_put_right:Nx \l_cntm_rightmost_branch_opt_tl { \cntmbranchopt ] }
    \tl_put_right:Nn \l_cntm_rightmost_branch_opt_tl { { \istactionlabelstyle { \cntmRightAL } } }
    \tl_put_right:Nx \l_cntm_rightmost_branch_opt_tl { [ \cntmRightALpos ] }
}


% \cntmAistb LEFT/RIGHT options:
% (still in the complication) collecting branch options input by \cntmAistb
% the collected token list will be used in \istrootcntmA and \istrootocntmA
% [ - , \cntmAbranchdrawopt ] { LEFT AL } [ LEFT pos ] { RIGHT AL } [ RIGHT pos ]
\cs_new:Npn \_collect_cntmA_leftmost_branch_opts:
{
    \tl_set:Nn \l_cntmA_leftmost_branch_opt_tl       { [ - , }
    \tl_put_right:Nx \l_cntmA_leftmost_branch_opt_tl { \cntmAbranchdrawopt ] }
    \tl_put_right:Nn \l_cntmA_leftmost_branch_opt_tl { { \istactionlabelstyle { \cntmALeftAL } } }
    \tl_put_right:Nx \l_cntmA_leftmost_branch_opt_tl { [ \cntmALeftALpos ] }
}

\cs_new:Npn \_collect_cntmA_rightmost_branch_opts:
{
    \tl_set:Nn \l_cntmA_rightmost_branch_opt_tl       { [ - , }
    \tl_put_right:Nx \l_cntmA_rightmost_branch_opt_tl { \cntmAbranchdrawopt ] }
    \tl_put_right:Nn \l_cntmA_rightmost_branch_opt_tl { { \istactionlabelstyle { \cntmARightAL } } }
    \tl_put_right:Nx \l_cntmA_rightmost_branch_opt_tl { [ \cntmARightALpos ] }
}


% complication needed to resolve tex expansion issues (for cntm triangle)
% this will be used to draw cntm triangle in \istrootcntm and \istrootcntmo
% [ - , draw = \cntmdrawcolor , fill = \cntmfillcolor ]
\cs_new:Npn \_collect_cntm_triangle_cmdstr:  
{
  	\tl_set:Nn \l_tmp_option_str_tl       { [ - , }
  	\tl_put_right:Nn \l_tmp_option_str_tl { draw = }
  	\tl_put_right:Nx \l_tmp_option_str_tl { \cntmdrawcolor , }
  	\tl_put_right:Nn \l_tmp_option_str_tl { fill = }
  	\tl_put_right:Nx \l_tmp_option_str_tl { \cntmfillcolor , }
  	\tl_put_right:Nx \l_tmp_option_str_tl { \cntmopt ] }
}


% \cntmOUTERistb
% modification of \istb for cntm outermost branches with NO PAYOFF
% this actually draws outermost branches (used in \istrootcntm and \istrootocntm)
\NewDocumentCommand \cntmOUTERistb 
{ s D<>{} O{} +G{} O{} }
{ 
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ #2 ] 
      { 
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow , #3 } { #5 } { #4 } 
        % the next must NOT go BEFORE \ist_move:nnn : PROBLEMatic (possibly TikZ problem)
        \IfBooleanTF  { #1 } { \cntm@ndot } { \cntm@show@endpoint }
      }
    }
}


% \cntmAOUTERistb
% modification of \istb for cntmA outermost branches with NO PAYOFF
% this actually draws outermost branches (used in \istrootcntmA and \istrootocntmA)
\NewDocumentCommand \cntmAOUTERistb 
{ s D<>{} O{} +G{} O{} +g O{\istgrowdirection} }
{ 
    \tl_put_right:Nn \ischo_game_tl
    { 
      child [ #2 ] 
      { 
        \ist_move:nnn { \xt@show@midarrow , \xt@show@arrow , #3 } { #5 } { #4 } 
        % the next must NOT go BEFORE \ist_move:nnn : PROBLEMatic (possibly TikZ problem)
        \IfBooleanTF  { #1 } { \cntm@ndot } { \cntm@show@endpoint }
      }
    }
}

% ------------
% complication so far needed to resolve tex expansion issues
% still more complication below
% ============


%% main macros: continuum of branches

% \istrootcntm -- standard cntm version
% ' [grow] (root) (at) [node style] <angle> {owner} +cntmlevdist..cntmsibdist+
\NewDocumentCommand \istrootcntm
{ t' O{\istdefault@grow} r() D(){0,0} O{} D<>{above} G{} d+. d.+ }
{ 
    % to suppress \xtShowArrows for cntm
    \let\tmp@xt@show@arrow\xt@show@arrow
    \def\xt@show@arrow { }
    \let\tmp@xt@show@midarrow\xt@show@midarrow
    \def\xt@show@midarrow { }

    % Now \_cntm_levdist_local_tl and \_cntm_sibdist_local_tl is the bases
    \IfNoValueTF {#8} 
    { 
      \bool_set_false:N \_cntm_distance_local_call_bool 
      \tl_set:Nn \_cntm_levdist_local_tl { \cntmlevdist } 
      \tl_set:Nn \_cntm_sibdist_local_tl { \cntmsibdist } 
    }
    { 
      \bool_set_true:N \_cntm_distance_local_call_bool
      \tl_set:Nn \_cntm_levdist_local_tl { #8 } 
      \tl_set:Nn \_cntm_sibdist_local_tl { #9 } 
    }
    
    % Now \_cntm_act_sibdist_tl is the base
    \bool_if:NTF \cntm_act_sibdist_call_bool
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl { \cntmACTsibdist }
    }
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl { 1/3 * \_cntm_sibdist_local_tl }
    }
    
    % adjust \cntm position for smaller triangle
    \pgfmathsetmacro \cntmlevdistVar { \cntmpos * \_cntm_levdist_local_tl } 
    \pgfmathsetmacro \cntmsibdistVar { \cntmpos * \_cntm_sibdist_local_tl } 

    %% \istroot(') : cntm outermost branches
    \tl_clear:N \ischo_game_tl
    \xdef\istgrowdirection{#2}
    
    % execute \ISTRoot [\istgrowdirection] (cntm) (#4) [null node] +{#8}..{#9}+
    % this defines (cntm)
    \IfBooleanTF {#1}
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot } }
    % collect arguments
    \tl_put_right:Nx \ischo_game_tl 
      { 
        [ \istgrowdirection ] (cntm) (#4) [ null~node ] 
        + { \cntmlevdistVar } .. { \cntmsibdistVar } + 
      }
 
    %% (before executing \istb) call options collected from above complication
    \_collect_cntm_leftmost_branch_opts: 
    \_collect_cntm_rightmost_branch_opts:
      
    % execute \istb \istb for cntm LEFT/RIGHT outermost branches
    % this defines (cntm-1) and (cntm-2)
    \exp_last_unbraced:NV \cntmOUTERistb \l_cntm_leftmost_branch_opt_tl
    \exp_last_unbraced:NV \cntmOUTERistb \l_cntm_rightmost_branch_opt_tl
    \printist ;
    
    %% draw cntm triangle, using (cntm), (cntm-1), (cntm-2)
    \begin{scope}[ shorten~< = 0pt , shorten~> = 0pt ]
    % call (draw and fill) options collected from above complication 
    \_collect_cntm_triangle_cmdstr:
    % and finally draw "cntm triangle"
    % \draw [opts] (cntm) -- (cntm-1) -- (cntm-2) - (cntm) ;
    \begin{pgfonlayer}{\cntm@default@layer} % default: background
      \exp_last_unbraced:No \draw \l_tmp_option_str_tl (cntm)--(cntm-1)--(cntm-2)--(cntm) ;
    \end{pgfonlayer}
    \end{scope}   
    
    %% cntm action (actually taken by a player)
    % this is normal \istroot(')
    \tl_clear:N \ischo_game_tl
    
    \IfBooleanTF {#1} 
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot } }
    % collect arguments 
    \tl_put_right:Nx \ischo_game_tl { [ \istgrowdirection ] (#3) (cntm) [#5] <#6> }
    \tl_put_right:Nn \ischo_game_tl { { \istownerstyle{ #7 } } }
    \tl_put_right:Nx \ischo_game_tl { +{ \_cntm_levdist_local_tl }..{ 1*\_cntm_act_sibdist_local_tl }+ }
        
    % call set (for \istbA)
    \bool_set_true:N \_istroot_cntm_call_bool    % for \istbA
    
    % back to normal \xtShowArrows
    \let\xt@show@arrow\tmp@xt@show@arrow 
    \let\xt@show@midarrow\tmp@xt@show@midarrow
}


% resolving expansion issue (for cntmA)
% [ - , tension=1 , \cntmAopt ]
\cs_new:Npn \_collect_cntmA_cmdstr:
{
  	\tl_set:Nn \l_tmp_arc_option_str_tl       { [ - , tension=1 , }
  	\tl_put_right:Nx \l_tmp_arc_option_str_tl { \cntmAopt ] }
}

% [ - , tension=1 , \cntmAfillcolor ]
\cs_new:Npn \_collect_cntmA_color_cmdstr:
{
  	\tl_set:Nn \l_tmp_arc_color_str_tl       { [ - , tension=1 , }
  	\tl_put_right:Nx \l_tmp_arc_color_str_tl { \cntmAfillcolor ] }
}

% \istrootcntmA -- cntm arc version
% ' [grow] (root) (at) [node style] <angle> {owner} +cntmlevdist..cntmsibdist+
\NewDocumentCommand \istrootcntmA
{ t' O{\istdefault@grow} r() D(){0,0} O{} D<>{above} G{} d+. d.+ }
{ 
    % to suppress \xtShowArrows for cntm
    \let\tmp@xt@show@arrow\xt@show@arrow
    \def\xt@show@arrow { }
    \let\tmp@xt@show@midarrow\xt@show@midarrow
    \def\xt@show@midarrow { }

    % Now \_cntm_levdist_local_tl and \_cntm_sibdist_local_tl is the bases
    \IfNoValueTF {#8} 
    { 
      \bool_set_false:N \_cntmA_distance_local_call_bool 
      \tl_set:Nn \_cntmA_levdist_local_tl { \cntmlevdist } 
      \tl_set:Nn \_cntmA_sibdist_local_tl { \cntmsibdist } 
    }
    { 
      \bool_set_true:N \_cntmA_distance_local_call_bool
      \tl_set:Nn \_cntmA_levdist_local_tl { #8 } 
      \tl_set:Nn \_cntmA_sibdist_local_tl { #9 } 
    }

    % Now \_cntm_act_sibdist_tl is the base
    \bool_if:NTF \cntm_act_sibdist_call_bool
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl {\cntmACTsibdist}
    }
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl {1/3*\_cntmA_sibdist_local_tl}
    }
    
    %% \ISTRoot(') : for drawing cntmA outermost branches
    \tl_clear:N \ischo_game_tl
    \xdef\istgrowdirection{#2}
    
    % execute \ISTRoot
    % this defines (cntm)
    \IfBooleanTF {#1}
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot } }    
    % collect arguments
    \tl_put_right:Nx \ischo_game_tl 
      { [ \istgrowdirection ] (cntm) (#4) [ null~node ] 
        +{\_cntmA_levdist_local_tl}..{\_cntmA_sibdist_local_tl}+ }

    %% (before executing \istb) call options collected from above complication
    \_collect_cntmA_leftmost_branch_opts:
    \_collect_cntmA_rightmost_branch_opts:
    
    % execute \istb \istb for cntmA LEFT/RIGHT outermost branches
    % this defines (cntm-1) and (cntm-2)
    \exp_last_unbraced:NV \cntmAOUTERistb \l_cntmA_leftmost_branch_opt_tl
    \exp_last_unbraced:NV \cntmAOUTERistb \l_cntmA_rightmost_branch_opt_tl
    \printist ;
    
    %% defining cntmA points
    % First, adjust plot vertex to compensate dependency of tree shape
    \pgfmathsetmacro\cntmdistratio{ scalar (\_cntmA_levdist_local_tl/\_cntmA_sibdist_local_tl) }
    % sqrt(1/3) is to make the cntmdist ratio 1/3 as standard
    \pgfmathsetmacro\cntmAplotfactorVal
      { 1 + (\cntmAplotfactor-1) * sqrt(1/3) / sqrt(\cntmdistratio) }
    \xdef\cntmAplotfactorAdj{\cntmAplotfactorVal} % used also in \istbA(t)
    \coordinate (cntmA-beg) at ( $ (cntm) ! \cntmApos ! (cntm-1) $ ) ; % begin point
    \coordinate (cntmA-end) at ( $ (cntm) ! \cntmApos ! (cntm-2) $ ) ; % end point
    \coordinate (cntmA-mid-base) at ( $ (cntm-1) ! .5 ! (cntm-2)$) ; % base midpoint
    % defines "compensated" plot vertex
    \coordinate (cntmA-vertex) 
      at ( $ (cntm) ! \cntmAplotfactorAdj*\cntmApos ! (cntmA-mid-base) $ ) ;
    % (for expost/outside use)
    \coordinate (cntmAi-begpoint) at ( $ (cntm) ! \cntmApos ! (cntm-1) $ ) ;
    \coordinate (cntmAi-endpoint) at ( $ (cntm) ! \cntmApos ! (cntm-2) $ ) ;
    
    %% plot cntmA
    % \draw [ \cntmAopt , - , <opts> , tension=1 ]
    \_collect_cntmA_cmdstr:
    \_collect_cntmA_color_cmdstr:
    
    \begin{scope}[ shorten~< = 0pt , shorten~> = 0pt ]
    \begin{pgfonlayer}{\cntmAdefaultlayer} % default: behind
    \exp_last_unbraced:No \fill \l_tmp_arc_color_str_tl 
      (cntm) -- plot [ smooth ] coordinates { (cntmA-beg) (cntmA-vertex) (cntmA-end) } -- cycle ;
    \exp_last_unbraced:No \draw \l_tmp_arc_option_str_tl
      plot [ smooth ] coordinates { (cntmA-beg) (cntmA-vertex) (cntmA-end) } ;
    \end{pgfonlayer}
    \end{scope}

    %% cntmA action (actually taken by a player)
    % this is normal \istroot(')
    \tl_clear:N \ischo_game_tl
    
    \IfBooleanTF {#1} 
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRoot } }
    % collect arguments 
    \tl_put_right:Nx \ischo_game_tl { [ \istgrowdirection ] (#3) (cntm) [#5] <#6> }
    \tl_put_right:Nn \ischo_game_tl { { \istownerstyle{ #7 } } }
    \tl_put_right:Nx \ischo_game_tl { +{ \_cntmA_levdist_local_tl }..{ 1*\_cntm_act_sibdist_local_tl }+ }
    
    % call set (for \istbA)
    \bool_set_true:N \_istroot_cntmA_call_bool
    
    % back to normal \xtShowArrows
    \let\xt@show@arrow\tmp@xt@show@arrow
    \let\xt@show@midarrow\tmp@xt@show@midarrow
}

% \cntmAexpostShowEndPoints
% use this right after \istrootcntmA and \istrootocntmA 
%               (before \cntmAInfoset and \cntmAInfosetO)
\NewDocumentCommand \cntmAexpostShowEndPoints
{ O{} O{} }
{
%\begin{pgfonlayer}{above} % main is ok
\node [ solid~node , #1 ] at (cntmAi-begpoint)  {} ;
\node [ solid~node , #2 ] at (cntmAi-endpoint)  {} ;
%\end{pgfonlayer}
}


% \istrootocntm -- oval cntm version
% ' [grow] (root) (at) [node style] <angle> {owner} +cntmlevdist..cntmsibdist+
\NewDocumentCommand \istrootocntm
{ t' O{\istdefault@grow} r() D(){0,0} O{} D<>{above} G{} d+. d.+ }
{ 
    % to suppress \xtShowArrows for cntm
    \let\tmp@xt@show@arrow\xt@show@arrow
    \def\xt@show@arrow { }
    \let\tmp@xt@show@midarrow\xt@show@midarrow
    \def\xt@show@midarrow { }

    % Now \_cntm_levdist_local_tl and \_cntm_sibdist_local_tl is the bases
    \IfNoValueTF {#8} 
    { 
      \bool_set_false:N \_cntm_distance_local_call_bool 
      \tl_set:Nn \_cntm_levdist_local_tl { \cntmlevdist } 
      \tl_set:Nn \_cntm_sibdist_local_tl { \cntmsibdist } 
    }
    { 
      \bool_set_true:N \_cntm_distance_local_call_bool
      \tl_set:Nn \_cntm_levdist_local_tl { #8 } 
      \tl_set:Nn \_cntm_sibdist_local_tl { #9 } 
    }
    
    % Now \_cntm_act_sibdist_tl is the base
    \bool_if:NTF \cntm_act_sibdist_call_bool
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl {\cntmACTsibdist}
    }
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl {1/3*\_cntm_sibdist_local_tl}
    }
    
    % adjust \cntm position for smaller triangle
    \pgfmathsetmacro\cntmlevdistVar{\cntmpos*\_cntm_levdist_local_tl} 
    \pgfmathsetmacro\cntmsibdistVar{\cntmpos*\_cntm_sibdist_local_tl} 

    %% \istrooto(') : cntm outermost branches
    \tl_clear:N \ischo_game_tl
    \xdef\istgrowdirection{#2}
    
    % execute \ISTRoot [\istgrowdirection] (cntm) (#4) [null node] +{#8}..{#9}+
    % this defines (cntm)
    \IfBooleanTF {#1}
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO } }
    % collect arguments
    \tl_put_right:Nx \ischo_game_tl 
      { 
        [ \istgrowdirection ] (cntm) (#4) [ null~node ] 
        +{\cntmlevdistVar}..{\cntmsibdistVar}+ 
      }
 
    %% (before executing \istb) call options collected from above complication
    \_collect_cntm_leftmost_branch_opts: 
    \_collect_cntm_rightmost_branch_opts:
      
    % execute \istb \istb for cntm LEFT/RIGHT outermost branches
    % this defines (cntm-1) and (cntm-2)
    \exp_last_unbraced:NV \cntmOUTERistb \l_cntm_leftmost_branch_opt_tl
    \exp_last_unbraced:NV \cntmOUTERistb \l_cntm_rightmost_branch_opt_tl
    \printist ;
    
    %% draw cntm triangle, using (cntm), (cntm-1), (cntm-2)
    \begin{scope}[ shorten~< = 0pt , shorten~> = 0pt ]
    % call (draw and fill) options collected from above complication 
    \_collect_cntm_triangle_cmdstr:
    % and finally draw "cntm triangle"
    % \draw [opts] (cntm) -- (cntm-1) -- (cntm-2) - (cntm) ;
    \begin{pgfonlayer}{\cntm@default@layer} % default: background
      \exp_last_unbraced:No \draw \l_tmp_option_str_tl (cntm)--(cntm-1)--(cntm-2)--(cntm) ;
    \end{pgfonlayer}
    \end{scope}   
    
    %% cntm action (actually taken by a player)
    % this is normal \istrooto(')
    \tl_clear:N \ischo_game_tl
    
    \IfBooleanTF {#1} 
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO } }
    % collect arguments 
    \tl_put_right:Nx \ischo_game_tl { [ \istgrowdirection ] (#3) (cntm) [#5] <#6> }
    \tl_put_right:Nn \ischo_game_tl { { \istownerstyle{ #7 } } }
    \tl_put_right:Nx \ischo_game_tl { +{ \_cntm_levdist_local_tl }..{ 1*\_cntm_act_sibdist_local_tl }+ }
        
    % call set (for \istbA)
    \bool_set_true:N \_istroot_cntm_call_bool  % for \istbA  (HERE, USE \_istroot_ but not \_istrooto_ )
    
    % back to normal \xtShowArrows
    \let\xt@show@arrow\tmp@xt@show@arrow 
    \let\xt@show@midarrow\tmp@xt@show@midarrow
}

% \istrootocntmA -- oval cntm arc version
% ' [grow] (root) (at) [node style] <angle> {owner} +cntmlevdist..cntmsibdist+
\NewDocumentCommand \istrootocntmA
{ t' O{\istdefault@grow} r() D(){0,0} O{} D<>{above} G{} d+. d.+ }
{ 
    % to suppress \xtShowArrows for cntm
    \let\tmp@xt@show@arrow\xt@show@arrow
    \def\xt@show@arrow { }
    \let\tmp@xt@show@midarrow\xt@show@midarrow
    \def\xt@show@midarrow { }

    % Now \_cntm_levdist_local_tl and \_cntm_sibdist_local_tl is the bases
    \IfNoValueTF {#8} 
    { 
      \bool_set_false:N \_cntmA_distance_local_call_bool 
      \tl_set:Nn \_cntmA_levdist_local_tl { \cntmlevdist } 
      \tl_set:Nn \_cntmA_sibdist_local_tl { \cntmsibdist } 
    }
    { 
      \bool_set_true:N \_cntmA_distance_local_call_bool
      \tl_set:Nn \_cntmA_levdist_local_tl { #8 } 
      \tl_set:Nn \_cntmA_sibdist_local_tl { #9 } 
    }

    % Now \_cntm_act_sibdist_tl is the base
    \bool_if:NTF \cntm_act_sibdist_call_bool
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl {\cntmACTsibdist}
    }
    {
      \tl_set:Nn \_cntm_act_sibdist_local_tl {1/3*\_cntmA_sibdist_local_tl}
    }
    
    %% \ISTRootO(') : for drawing cntmA outermost branches
    \tl_clear:N \ischo_game_tl
    \xdef\istgrowdirection{#2}
    
    % execute \ISTRootO
    % this defines (cntm)
    \IfBooleanTF {#1}
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO } }    
    % collect arguments
    \tl_put_right:Nx \ischo_game_tl 
      { [ \istgrowdirection ] (cntm) (#4) [ null~node ] 
        +{\_cntmA_levdist_local_tl}..{\_cntmA_sibdist_local_tl}+ }

    %% (before executing \istb) call options collected from above complication
    \_collect_cntmA_leftmost_branch_opts:
    \_collect_cntmA_rightmost_branch_opts:
    
    % execute \istb \istb for cntmA LEFT/RIGHT outermost branches
    % this defines (cntm-1) and (cntm-2)
    \exp_last_unbraced:NV \cntmAOUTERistb \l_cntmA_leftmost_branch_opt_tl
    \exp_last_unbraced:NV \cntmAOUTERistb \l_cntmA_rightmost_branch_opt_tl
    \printist ;
    
    %% defining cntmA points
    % First, adjust plot vertex to compensate dependency of tree shape
    \pgfmathsetmacro\cntmdistratio{ scalar (\_cntmA_levdist_local_tl/\_cntmA_sibdist_local_tl) }
    % sqrt(1/3) is to make the cntmdist ratio 1/3 as standard
    \pgfmathsetmacro\cntmAplotfactorVal
      { 1 + (\cntmAplotfactor-1) * sqrt(1/3) / sqrt(\cntmdistratio) }
    \xdef\cntmAplotfactorAdj{\cntmAplotfactorVal} % used also in \istbA(t)
    \coordinate (cntmA-beg) at ( $ (cntm) ! \cntmApos ! (cntm-1) $ ) ; % begin point
    \coordinate (cntmA-end) at ( $ (cntm) ! \cntmApos ! (cntm-2) $ ) ; % end point
    \coordinate (cntmA-mid-base) at ( $ (cntm-1) ! .5 ! (cntm-2)$) ; % base midpoint
    % defines "compensated" plot vertex
    \coordinate (cntmA-vertex) 
      at ( $ (cntm) ! \cntmAplotfactorAdj*\cntmApos ! (cntmA-mid-base) $ ) ;
    % (for expost/outside use)
    \coordinate (cntmAi-begpoint) at ( $ (cntm) ! \cntmApos ! (cntm-1) $ ) ;
    \coordinate (cntmAi-endpoint) at ( $ (cntm) ! \cntmApos ! (cntm-2) $ ) ;
    
    %% plot cntmA
    % \draw [ \cntmAopt , - , <opts> , tension=1 ]
    \_collect_cntmA_cmdstr:
    \_collect_cntmA_color_cmdstr:
    
    \begin{scope}[ shorten~< = 0pt , shorten~> = 0pt ]
    \begin{pgfonlayer}{\cntmAdefaultlayer} % default: behind
    \exp_last_unbraced:No \fill \l_tmp_arc_color_str_tl 
      (cntm) -- plot [ smooth ] coordinates { (cntmA-beg) (cntmA-vertex) (cntmA-end) } -- cycle ;
    \exp_last_unbraced:No \draw \l_tmp_arc_option_str_tl
      plot [ smooth ] coordinates { (cntmA-beg) (cntmA-vertex) (cntmA-end) } ;
    \end{pgfonlayer}
    \end{scope}

    %% cntmA action (actually taken by a player)
    % this is normal \istrooto(')
    \tl_clear:N \ischo_game_tl
    
    \IfBooleanTF {#1} 
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO' } }
      { \tl_put_right:Nn \ischo_game_tl { \ISTRootO } }
    % collect arguments 
    \tl_put_right:Nx \ischo_game_tl { [ \istgrowdirection ] (#3) (cntm) [#5] <#6> }
    \tl_put_right:Nn \ischo_game_tl { { \istownerstyle{ #7 } } }
    \tl_put_right:Nx \ischo_game_tl { +{ \_cntmA_levdist_local_tl }..{ 1*\_cntm_act_sibdist_local_tl }+ }

    % call set (for \istbA)
    \bool_set_true:N \_istroot_cntmA_call_bool
    
    % back to normal \xtShowArrows
    \let\xt@show@arrow\tmp@xt@show@arrow
    \let\xt@show@midarrow\tmp@xt@show@midarrow
}


%% OBSOLETE macros - backward compatibility (to be removed next update)

% \obsoleteISTCntm (obsolete) - backward compatibility
% (used in \istcntm)
\NewDocumentCommand \obsoleteISTCntm
{ t' O{south} r() D(){0,0} O{\cntm@default@drawcolor} G{.5} 
  D+.{\cntmdefaultlevdist} D.+{\cntmdefaultsibdist} }
{
    \cntmdistance{#7}{#8}
    \tikzset{level~1/.style={level~distance=\cntmlevdist,sibling~distance=\cntmsibdist}}
    %
    \IfBooleanTF {#1}
    {
      \setistNullNodeStyle[#5]{\istdefault@null@nodesize}[#5]
      \begin{pgfonlayer}{background}
      \node (#3) at (#4) [ null~node ] { } [ \xt@growswap = #2 ] child child ;
      \draw [ #5 , fill = #5 ] (#3) -- (#3-1) -- (#3-2) -- (#3) ;
      \end{pgfonlayer}
      \setistNullNodeStyle{\istdefault@null@nodesize}
    }
    {
      \setistNullNodeStyle[#5]{\istdefault@null@nodesize}[#5]
      \begin{pgfonlayer}{background}
      \node (#3) at (#4) [ null~node ] { } [ \xt@grow = #2 ] child child ;
      \draw [ #5 , fill = #5 ] (#3) -- (#3-1) -- (#3-2) -- (#3) ;
      \end{pgfonlayer}
      \setistNullNodeStyle{\istdefault@null@nodesize}
    }
}

% \obsoleteISTCntmArc (arc version) (obsolete) - backward compatibility
% (used in \istcntmA)
\NewDocumentCommand \obsoleteISTCntmArc
{ t' O{south} r() D(){0,0} O{} G{.5} D+.{\cntmdefaultlevdist} D.+{\cntmdefaultsibdist} }
{
    \cntmdistance{#7}{#8}
    \tikzset{level~1/.style={level~distance=\cntmlevdist,sibling~distance=\cntmsibdist}}
    %
    \IfBooleanTF {#1}
    { 
      \begin{pgfonlayer}{background}
      \node (#3) at (#4) [ null~node ] { } [\xt@growswap=#2] child child ;
      \draw [ bend~left , #5 ] ( $ (#3) ! #6 ! (#3-1) $ ) to ( $ (#3) ! #6 ! (#3-2) $ ) ;
      \end{pgfonlayer}
    }
    { 
      \begin{pgfonlayer}{background}
      \node (#3) at (#4) [ null~node ] { } [\xt@grow=#2] child child ;
      \draw [ bend~right , #5 ] ( $ (#3) ! #6 ! (#3-1) $ ) to ( $ (#3) ! #6 ! (#3-2) $ ) ;
      \end{pgfonlayer}
    }
}


% \istcntm(')  (obsolete) - backward compatibility
\NewDocumentCommand \istcntm 
{ t' O{\istdefault@grow} r() D(){0,0} O{\cntm@default@drawcolor} G{} 
  D+.{\cntmdefaultlevdist} D.+{\cntmdefaultsibdist} }
{ 
    \xdef\istgrowdirection{#2}  % used in \istb to specify [payoff direction]
    \IfBooleanTF {#1}
    {
      \obsoleteISTCntm' [ \istgrowdirection ] ( #3 ) ( #4 ) [ #5 ] + #7 .. #8 +
    }
    {
      \obsoleteISTCntm  [ \istgrowdirection ] ( #3 ) ( #4 ) [ #5 ] + #7 .. #8 +
    }
}

% \istcntmarc(') (obsolete) - backward compatibility
\NewDocumentCommand \istcntmarc
{ t' O{\istdefault@grow} r() D(){0,0} O{} G{.5} D+.{\cntmdefaultlevdist} D.+{\cntmdefaultsibdist} }
{     
    \xdef\istgrowdirection{#2}  % used in \istb to specify [payoff direction]
    \IfBooleanTF {#1}
    {
      \obsoleteISTCntmArc' [ \istgrowdirection ] ( #3 ) ( #4 ) [ #5 ] { #6 } + #7 .. #8 +
    }
    {
      \obsoleteISTCntmArc  [ \istgrowdirection ] ( #3 ) ( #4 ) [ #5 ] { #6 }+ #7 .. #8 +
    }
}


%% supplementary macros

%% \xInfosetOwner (with abbreviations)
% * (from) (to) {owner} [pos]
\NewDocumentCommand \xtInfosetOwner{ s r() r() +m O{} }
{ 
    \begin{scope} % in group: to make \setistmathTF011 local
    \IfBooleanTF { #1 } { } { \setistmathTF011 \istownertextfont{} }
%    \str_case_e:nnF { #5 }
    \str_case:nnF { #5 }
    {
      { al } { \node [ above~left ]  at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { ar } { \node [ above~right ] at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { bl } { \node [ below~left ]  at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { br } { \node [ below~right ] at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { l }  { \node [ left ]        at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { r }  { \node [ right ]       at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { a }  { \node [ above ]       at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
      { b }  { \node [ below ]       at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ; }
    }
    {
               \node [ #5 ]          at ( $ (#2)!.5!(#3) $ ) { \istownerstyle{#4} } ;
    }
    \end{scope}
}

% \xtOwner (with abbreviations)
% * (coor) {owner} [pos]
\NewDocumentCommand \xtOwner{ s r() +m O{} }
{ 
    \begin{scope} % in group: to make \setistmathTF011 local
    \IfBooleanTF { #1 } { } { \setistmathTF011 \istownertextfont{} }
%    \str_case_e:nnF { #4 }
    \str_case:nnF { #4 }
    {
      { al } { \node [ above~left ]  at (#2) { \istownerstyle{#3} } ; }
      { ar } { \node [ above~right ] at (#2) { \istownerstyle{#3} } ; }
      { bl } { \node [ below~left ]  at (#2) { \istownerstyle{#3} } ; }
      { br } { \node [ below~right ] at (#2) { \istownerstyle{#3} } ; }
      { l }  { \node [ left ]        at (#2) { \istownerstyle{#3} } ; }
      { r }  { \node [ right ]       at (#2) { \istownerstyle{#3} } ; }
      { a }  { \node [ above ]       at (#2) { \istownerstyle{#3} } ; }
      { b }  { \node [ below ]       at (#2) { \istownerstyle{#3} } ; }
    }
    {
               \node [ above , #4 ]  at (#2) { \istownerstyle{#3} } ;
    }
    \end{scope}
}

% \xtActionLabel
% BE CAREFUL: each case has different options (do not try to shorten)
% * [opt] (parent) (child) {action label} [pos]
\NewDocumentCommand \xtActionLabel{ s O{} r() r() G{} O{} }
{ 
    \begin{scope} % in group: to make \setistmathTF011 local
    \IfBooleanTF { #1 } { } { \setistmathTF011 \istactionlabeltextfont{} }
%    \str_case_e:nnF { #6 }
    \str_case:nnF { #6 }
    {
      { al } {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ above~left , black , text~depth = .25ex ,
                                            xshift =  \istactionlabelxshift ,
                                            yshift = -\istactionlabelyshift ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { ar } {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ above~right , black , text~depth = .25ex ,
                                            xshift = -\istactionlabelxshift ,
                                            yshift = -\istactionlabelyshift ]
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { bl } {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ below~left , black , text~depth = .25ex ,
                                            xshift =  \istactionlabelxshift ,
                                            yshift =  \istactionlabelyshift ]
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { br } {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ below~right , black , text~depth = .25ex ,
                                            xshift = -\istactionlabelxshift ,
                                            yshift =  \istactionlabelyshift ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { l }  {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ left , black , text~depth = .25ex ,
                                            yshift = -\xtALyShift ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { r }  {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ right , black , text~depth = .25ex ,
                                            yshift =  \xtALyShift ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { a }  {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ above , black , text~depth = .25ex ,
                                            yshift =  \xtALyShift ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
      { b }  {
               \draw [ - , draw = none , #2 ] (#3) to 
                     [ edge~node = { node [ below , black , text~depth = .25ex ,
                                            yshift = -\xtALyShift ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ; 
             }
    }
    {
               \draw [ - , draw = none , #2] (#3) to 
                     [ edge~node = { node [ black , text~depth = .25ex , #6 ] 
                                          { \istactionlabelstyle{#5} } } ] (#4) ;
    }
    \end{scope}
}



\def\xtdefault@xtpayoff@outersep{4pt}
% \xtPayoff (with abbreviations)
% * (coor) {payoffs} [pos]
\NewDocumentCommand \xtPayoff{ s r() +m O{below} }
{ 
    \begin{scope} % in group: to make \setistmathTF011 local
    \IfBooleanTF { #1 } { } { \setistmathTF011 \istpayofftextfont{} }
%    \str_case_e:nnF { #4 }
    \str_case:nnF { #4 }
    {
      { al } {
               \node [ above~left , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ] 
                     at (#2) { \istpayoffstyle{#3} } ; 
             }
      { ar } {
               \node [ above~right , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ]
                     at (#2) { \istpayoffstyle{#3} } ; 
             }
      { bl } {
               \node [ below~left , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ]
                     at (#2) { \istpayoffstyle{#3} } ; 
             }
      { br } {
               \node [ below~right , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ]
                     at (#2) { \istpayoffstyle{#3} } ; 
             }
      { l }  { 
               \node [ left , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ] 
                     at (#2) { \istpayoffstyle{#3} } ; 
             }
      { r }  { 
               \node [ right , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ] 
                     at (#2) { \istpayoffstyle{#3} } ; }
      { a }  { 
               \node [ above , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ] 
                     at (#2) { \istpayoffstyle{#3} } ; }
      { b }  { 
               \node [ below , inner~sep = 0pt , 
                       outer~sep = \xtdefault@xtpayoff@outersep , text~depth = .25ex ] 
                     at (#2) { \istpayoffstyle{#3} } ; }
    }
    {
               \node [ inner~sep = 0pt , outer~sep = \xtdefault@xtpayoff@outersep , 
                       text~depth = .25ex , #4 ] 
                     at (#2) { \istpayoffstyle{#3} } ;
    }
    \end{scope}
}


% \xtNode(*)
% * [opt] (coor) [node style] {text}
\NewDocumentCommand \xtNode{ s O{} r() O{} +G{} }
{ \IfBooleanTF {#1}
    {
      \istrooto (#3) (#3) [ plain~node , #4 ] {#5} \printist ;
    }
    {
      \node [ - , #2 ] at (#3)  [ solid~node , #4 ] {#5} ;
    }
}


%% show and hide endpoints

\NewDocumentCommand \xtShowEndPoints{ s O{solid~node} }
{ \IfBooleanTF {#1}
    {
      \def\xt@show@endpoint{node[#2]{}}
      \def\xt@show@tndot{node[#2]{}}
      \def\cntm@show@endpoint{node[at~end,#2]{}} %% PROBLEMatic: node [#2] (ref. \cntmOUTERistb)
    }
    {
      \def\xt@show@endpoint{node[#2]{}}
      \def\xt@show@tndot{node[#2]{}}
    }
}

\NewDocumentCommand \xtHideEndPoints{s}
{
    \IfBooleanTF {#1}
    { % works only for cntm
      \renewcommand*\cntm@show@endpoint{}
    }
    {
      \renewcommand*\xt@show@endpoint{}
      \renewcommand*\xt@show@tndot{}
    }
}

%% show and hide terminal nodes

\NewDocumentCommand \xtShowTerminalNodes{ O{terminal~node} }
{
    \def\xt@show@tndot{node[#1]{}}
}

\NewDocumentCommand \xtHideTerminalNodes{}
{
    \renewcommand*\xt@show@tndot{}
}


%% subgames

% subgame box/oval layer
\def\xtdefault@subgamelayer { background }
\newcommand*\xtsubgamelayer{ \xtdefault@subgamelayer }
\NewDocumentCommand \setxtsubgamelayer { G{\xtdefault@subgamelayer} }
{
    \renewcommand \xtsubgamelayer { #1 }
}

\def\xtdefault@subrootshiftbox { 0 , -.3 }
% \xtSubgameBox
% * (root coor) { (coor1) (coor2)... } [additional opt]
\NewDocumentCommand \xtSubgameBox { s r() m O{} }
{
    \IfBooleanTF {#1}
    {
      \coordinate (xtsubroot) at ( $ (#2) + (\xtdefault@subrootshiftbox) $ ) ;
      \begin{pgfonlayer}{\xtsubgamelayer}
      \node [ rectangle , fill , red!20 , inner~sep = 20pt , rounded~corners = 15pt , #4 ] 
            [ fit = (xtsubroot) #3 ] { } ;
      \end{pgfonlayer}
    }
    {
      \coordinate (xtsubroot) at ( $ (#2) + ( 0 , -.3 ) $ ) ;
      \begin{pgfonlayer}{\xtsubgamelayer}
      \node [ rectangle , draw , dashed , inner~sep = 20pt , rounded~corners = 15pt , black!50 , #4 ] 
            [ fit = (xtsubroot) #3 ] {} ;
      \end{pgfonlayer}
    }
}

\def\xtdefault@subrootshiftoval { 0 , -.7 }
% \xtSubgameOval
% * (root coor) { (coor1) (coor2)... } [additional opt]
\NewDocumentCommand \xtSubgameOval { s r() m O{} }
{
    \IfBooleanTF {#1}
    {
      \coordinate (xtsubroot) at ( $ (#2) + (\xtdefault@subrootshiftoval) $ ) ;
      \begin{pgfonlayer}{\xtsubgamelayer}
        \node [ ellipse , fill , red!20 , inner~sep = 15pt , #4 ] 
              [ fit = (xtsubroot) #3 ] { } ;
      \end{pgfonlayer}
    }
    {
      \coordinate (xtsubroot) at ( $ (#2) + ( 0 , -.7 ) $ ) ;
      \begin{pgfonlayer}{\xtsubgamelayer} % borrowed from infoset
      \node [ ellipse , draw , dashed , inner~sep = 15pt , black!50 , #4 ] 
            [ fit = (xtsubroot) #3 ] { } ;
      \end{pgfonlayer}
    }
}

% \xtTimeLineH
% ' [line opt] (passing point) {from dim} {to dim} {label} [pos]
\NewDocumentCommand \xtTimeLineH { t' O{} r() m m G{} O{}}
{
    \bool_if:NTF \xt_growswap_call_bool
    { % if swapped, go opposite direction
        \pgfmathsetmacro \tlhAA { -1 * #4 }
        \pgfmathsetmacro \tlhBB { -1 * #5 }  
        \IfBooleanTF { #1 }
        {
          \coordinate (tlhCC) at ( #3 -| { \tlhBB , \tlhAA } ) ;
          \tl_set:Nn \_TH_label_pos_tl { left }
        }
        {
          \coordinate (tlhCC) at ( #3 -| { \tlhAA , \tlhBB } ) ;
          \tl_set:Nn \_TH_label_pos_tl { right }
        }  
    }
    {
        \def \tlhAA { #4 }
        \def \tlhBB { #5 } 
        \IfBooleanTF {#1}
        {
          \coordinate (tlhCC) at ( #3 -| { \tlhAA , \tlhBB } ) ;
          \tl_set:Nn \_TH_label_pos_tl { left }
        }
        {
          \coordinate (tlhCC) at ( #3 -| { \tlhBB , \tlhAA } ) ;
          \tl_set:Nn \_TH_label_pos_tl { right }
        }  
    }
    \begin{pgfonlayer}{\xtsubgamelayer}
%      \str_case_e:nnF {#7}
      \str_case:nnF {#7}
      {
        {al} { \node at (tlhCC) [ above~left ]  {#6} ; }
        {ar} { \node at (tlhCC) [ above~right ] {#6} ; }
        {bl} { \node at (tlhCC) [ below~left ]  {#6} ; }
        {br} { \node at (tlhCC) [ below~right ] {#6} ; }
        {l}  { \node at (tlhCC) [ left ]        {#6} ; }
        {r}  { \node at (tlhCC) [ right ]       {#6} ; }
        {a}  { \node at (tlhCC) [ above ]       {#6} ; }
        {b}  { \node at (tlhCC) [ below ]       {#6} ; }
      }
      {
        \node at ( tlhCC ) [ \_TH_label_pos_tl , #7 ] {#6} ;
      }
      \draw [ - , dotted , shorten~< = 0pt, shorten~> = 0pt , #2 ] 
            ( #3 -| { \tlhAA , \tlhBB } ) -- ( #3 -| { \tlhBB , \tlhAA } ) ;
    \end{pgfonlayer}
}


% \xtTimeLineV
% ' [line opt] (passing point) {from dim} {to dim} {label} [pos]
\NewDocumentCommand \xtTimeLineV { t' O{} r() m m G{} O{}}
{    
    \bool_if:NTF \xt_growswap_call_bool
    {
        \def\tlvAA{#4}
        \def\tlvBB{#5} 
        \IfBooleanTF {#1}
        {
          \coordinate (tlvCC) at ( #3 |- { \tlvAA , \tlvBB } ) ;
          \tl_set:Nn \_TH_label_pos_tl { right }
        }
        {
          \coordinate (tlvCC) at ( #3 |- { \tlvBB , \tlvAA } ) ;
          \tl_set:Nn \_TH_label_pos_tl { right }
        }  
    }
    { % if not swapped, go opposite direction
        \pgfmathsetmacro\tlvAA{-1*#4}
        \pgfmathsetmacro\tlvBB{-1*#5}  
        \IfBooleanTF {#1}
        {
          \coordinate (tlvCC) at ( #3 |- { \tlvBB , \tlvAA } ) ;
          \tl_set:Nn \_TH_label_pos_tl { right }
        }
        {
          \coordinate (tlvCC) at ( #3 |- { \tlvAA , \tlvBB } ) ;
          \tl_set:Nn \_TH_label_pos_tl { right }
        }  
    }
    
    \begin{pgfonlayer}{\xtsubgamelayer}
%      \str_case_e:nnF {#7}
      \str_case:nnF {#7}
      {
        {al} { \node at (tlvCC) [ above~left ]  {#6} ; }
        {ar} { \node at (tlvCC) [ above~right ] {#6} ; }
        {bl} { \node at (tlvCC) [ below~left ]  {#6} ; }
        {br} { \node at (tlvCC) [ below~right ] {#6} ; }
        {l}  { \node at (tlvCC) [ left ]        {#6} ; }
        {r}  { \node at (tlvCC) [ right ]       {#6} ; }
        {a}  { \node at (tlvCC) [ above ]       {#6} ; }
        {b}  { \node at (tlvCC) [ below ]       {#6} ; }
      }
      {
        \node at ( tlvCC ) [ \_TH_label_pos_tl , #7 ] {#6} ;
      }
      \draw [ - , dotted , shorten~< = 0pt, shorten~> = 0pt , #2 ] 
            ( #3 |- { \tlvBB , \tlvAA } ) -- ( #3 |- { \tlvAA , \tlvBB } ) ;
    \end{pgfonlayer}
}


%% \xtCommentTo
% [line opt] (absolute to-coor) (relative from-coor) {text} [pos] (arrow end shorten dim)
\NewDocumentCommand \xtCommentTo { O{} r() r() G{} O{} D(){1pt} }
{
    \draw [ -> , densely~dotted , shorten~< = 0pt , shorten~> = #6 , #1 ] 
          ( $ (#2) + (#3) $ ) to (#2) ;
%    \str_case_e:nnF {#5}
    \str_case:nnF {#5}
    {
      {al}  { \node at ( $ (#2) + (#3) $ ) [ above~left ]  {#4} ; }
      {ar}  { \node at ( $ (#2) + (#3) $ ) [ above~right ] {#4} ; }
      {bl}  { \node at ( $ (#2) + (#3) $ ) [ below~left ]  {#4} ; }
      {br}  { \node at ( $ (#2) + (#3) $ ) [ below~right ] {#4} ; }
      {l}   { \node at ( $ (#2) + (#3) $ ) [ left ]        {#4} ; }
      {r}   { \node at ( $ (#2) + (#3) $ ) [ right ]       {#4} ; }
      {a}   { \node at ( $ (#2) + (#3) $ ) [ above ]       {#4} ; }
      {b}   { \node at ( $ (#2) + (#3) $ ) [ below ]       {#4} ; }
    }
    {
      \node at ( $ (#2) + (#3) $ ) [ above, #5 ] {#4} ;
    }
}

%% \xtCommentFrom
% [line opt] (absolute from-coor) (absolute from-coor) {text} [pos] (arrow end shorten dim)
\NewDocumentCommand \xtCommentFrom{ O{} r() r() G{} O{} D(){1pt}}
{
    \draw [ -> , densely~dotted , shorten~< = 0pt , shorten~> = #6 , #1 ] (#2) to (#3) ;
%    \str_case_e:nnF {#5}
    \str_case:nnF {#5}
    {
      {al}  { \node at (#2) [ above~left ]  {#4} ; }  
      {ar}  { \node at (#2) [ above~right ] {#4} ; }  
      {bl}  { \node at (#2) [ below~left ]  {#4} ; }  
      {br}  { \node at (#2) [ below~right ] {#4} ; }  
      {l}   { \node at (#2) [ left ]        {#4} ; }  
      {r}   { \node at (#2) [ right ]       {#4} ; }  
      {a}   { \node at (#2) [ above ]       {#4} ; }  
      {b}   { \node at (#2) [ below ]       {#4} ; }  
    }
    {
      \node at (#2) [ above , #5 ] {#4} ;
    }
}

%% mid arrow styles: basics
% \xt@default... used

\def\xt@default@arrow@pos   { .55 }
\def\xt@arrow@pos           { \xt@default@arrow@pos }
\def\xt@default@arrow@opt   { black } % black needed here (not to depend on branch color)
\def\xt@arrow@opt           { \xt@default@arrow@opt }
\def\xt@default@arrow@shape { > }
\def\xt@arrow@shape         { \xt@default@arrow@shape }
\newcommand*\xtarrowpos     { \xt@arrow@pos }
\newcommand*\xtarrowopt     { \xt@arrow@opt }
\newcommand*\xtarrowshape   { \xt@arrow@shape }


% \setxtarrowtips
% to toss values to arrow tip styles
\NewDocumentCommand \setxtarrowtips
{
    D<>{ \xt@default@arrow@pos } 
    G{ \xt@default@arrow@shape } 
    O{ \xt@default@arrow@opt } 
}
{
    \renewcommand*\xt@arrow@pos   {#1}
    \renewcommand*\xt@arrow@shape {#2}
    \renewcommand*\xtarrowopt     { - , thin , solid , shorten~> = 0 , #3}
}
% initial set for defaults
\AtBeginDocument{\setxtarrowtips}

% variable style [->]: 
% accepts an option value changed by \xtarrowopt (this is better)
% alternative choice: use original value \xt@arrow@opt by default
\tikzset
{ ->- /.style =
  { 
    decoration =
    {
      markings ,
      mark = at~position~ #1 ~with~ 
             { \exp_last_unbraced:NNV \arrow [ \xtarrowopt ] { \xtarrowshape } }
    } ,
    postaction = {decorate}
  } ,
  ->-/.default = \xt@arrow@pos
}

\tikzset
{ ->>- /.style =
  { 
    decoration =
    {
      markings ,
      mark = at~position~ #1 ~with~ 
             { \exp_last_unbraced:NNo \arrow [ \xtarrowopt ] { >> } } 
    } ,
    postaction = {decorate}
  } ,
  ->>-/.default = .6
}

\tikzset
{ ->>>- /.style =
  { 
    decoration =
    {
      markings ,
      mark = at~position~ #1 ~with~ 
             { \exp_last_unbraced:NNo \arrow [ \xtarrowopt ] { >>> } } 
    } ,
    postaction = {decorate}
  } ,
  ->>>-/.default = .65
}

\tikzset
{ -o- /.style =
  { 
    decoration =
    {
      markings ,
      mark = at~position~ #1 ~with~ 
             { \exp_last_unbraced:NNo \arrow [ \xtarrowopt ] { o } } 
    } ,
    postaction = {decorate}
  } ,
  -o-/.default = .55
}

\tikzset
{ -x- /.style =
  { 
    decoration = 
    {
      markings ,
      mark 
      = at~position~ #1 ~with~ 
        { 
          \exp_last_unbraced:NNo \draw [ \xtarrowopt ]
                                       (-2pt,-2pt) -- (2pt,2pt);
          \exp_last_unbraced:NNo \draw [ \xtarrowopt ]
                                       (2pt,-2pt) -- (-2pt,2pt); 
        }
    } ,
    postaction = {decorate}
  } ,
  -x-/.default = .5
}


%% show midarrows

\def\xt@show@midarrow               { }
\def\xt@default@show@midarrow@pos   { .55 }
\def\xt@show@midarrow@pos           { \xt@default@show@midarrow@pos }
\def\xt@default@show@midarrow@opt   { black }
\def\xt@show@midarrow@opt           { \xt@default@show@midarrow@opt }
\def\xt@default@show@midarrow@shape { >}
\def\xt@show@midarrow@shape         { \xt@default@show@midarrow@shape }
\newcommand*\xtshowmidarrowpos      { \xt@show@midarrow@pos }
\newcommand*\xtshowmidarrowopt      { \xt@show@midarrow@opt }
\newcommand*\xtshowmidarrowshape    { \xt@show@midarrow@shape }

% \setxtshowmidarrows (for simple tree)
% to toss values to [show~midarrow]
\NewDocumentCommand \setxtshowmidarrows
{ 
    D<>{ \xt@default@show@midarrow@pos } 
    G{ \xt@default@show@midarrow@shape } 
    O{ \xt@default@show@midarrow@opt } 
}
{
    \renewcommand*\xt@show@midarrow@pos   {#1} % default: .55
    \renewcommand*\xt@show@midarrow@shape {#2}
    \renewcommand*\xtshowmidarrowopt      {#3}
}


% show midarrow style
\tikzset { stoppostaction/.code = { \let \tikz@postactions \pgfutil@empty } }
\tikzset
{ show~midarrow /.style = 
    { 
      decoration =
      {
        markings ,
        mark = { at~position~ #1 ~with~ 
                 { \exp_last_unbraced:NNV 
                   \arrow [ \xtshowmidarrowopt ] { \xt@show@midarrow@shape } }
               } 
      } ,
      postaction = { stoppostaction , decorate }
    } ,
    show~midarrow/.default = \xt@show@midarrow@pos % default: .55
}


% \xtShowMidArrows
% on [show~midarrow]
\NewDocumentCommand \xtShowMidArrows{ }
{
    \renewcommand*\xt@show@midarrow { show~midarrow }
}

% \xtHideMidArrows
% off [show~midarrow]
\NewDocumentCommand \xtHideMidArrows { }
{
    \renewcommand \xt@show@midarrow { }
}


%% show arrows

\def\xt@show@arrow                 { }
\def\xt@default@show@arrow@pos     { .55 }
\def\xt@show@arrow@pos             { \xt@default@show@arrow@pos }
\def\xt@default@show@arrow@opt     { black }
\def\xt@show@arrow@opt             { \xt@default@show@arrow@opt }
\def\xt@default@show@arrow@shape   { > }
\def\xt@show@arrow@shape           { \xt@default@show@arrow@shape }
\def\xt@default@show@arrow@shorten { 1.2pt }
\def\xt@show@arrow@shorten         { \xt@default@show@arrow@shorten }
\newcommand*\xtshowarrowpos        { \xt@show@arrow@pos }
\newcommand*\xtshowarrowopt        { \xt@show@arrow@opt }
\newcommand*\xtshowarrowshape      { \xt@show@arrow@shape }
\newcommand*\xtshowarrowshorten    { \xt@show@arrow@shorten }

% \setxtshowarrows
% to toss values to [show~arrow]
\NewDocumentCommand \setxtshowarrows
{ 
    G{>} 
    O{\xt@default@show@arrow@opt} 
    D(){\xt@default@show@arrow@shorten} 
}
{
    \renewcommand*\xt@show@arrow@shape{#1}   % default: >
    \renewcommand*\xtshowarrowopt{#2}        % default: black
    \renewcommand*\xt@show@arrow@shorten{#3} % default: 1.2pt
}

% show arrow style
\tikzset{stoppostaction/.code={\let\tikz@postactions\pgfutil@empty}}
\tikzset
{ show~arrow /.style = 
    { 
      decoration =
      {
        markings ,
        mark = { 
                 at~position~ 1 + - \pgf@shorten@end@additional + - #1 ~with~ 
                 { \exp_last_unbraced:NNV 
                   \arrow [ \xtshowarrowopt ] { \xt@show@arrow@shape } }
               } 
      } ,
      postaction = { stoppostaction , decorate }
    } ,
    show~arrow/.default = \xt@show@arrow@shorten % default: 1.2pt
}

% \xtShowArrows
% on [show~arrow]
\NewDocumentCommand \xtShowArrows { O{solid~node} }
{ 
    \xtShowEndPoints[#1]
    \renewcommand*\xt@show@arrow { show~arrow }
}

% \xtHideArrows
% off [show~arrow]
\NewDocumentCommand \xtHideArrows { s }
{
    \IfBooleanTF {#1} { \xtShowEndPoints } { \xtHideEndPoints }
    \renewcommand\xt@show@arrow { }
}

\ExplSyntaxOff 
\endinput