[Tex/LaTex] Define a variable containing color

colortikz-pgf

We can define a variable and pass it to a module using

\pgfmathsetmacro\j{6}

Which it means j=6, How can I define a variable for a color, I mean I want to pass color to a module

\pgfmathsetmacro\colr{white}

But I encountered Unknown function 'white'. How can I solve it?!
I have the below code

\usepackage{xcolor}
\usepackage{tikz}
\usetikzlibrary{arrows.meta}
\usetikzlibrary{calc}
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{appendix}
\usepackage{array,textcomp}
\usepackage[latin1]{inputenc}
\usetikzlibrary{bayesnet}
\usetikzlibrary{positioning}
\usepackage{color}
\usepackage{caption}
\pgfmathsetseed{5}
\makeatletter
\DeclareRobustCommand{\rvdots}{%
  \vbox{
    \baselineskip4\p@\lineskiplimit\z@
    \kern-\p@
    \hbox{.}\hbox{.}\hbox{.}
  }}
\makeatother
\tikzset{main/.style={circle, minimum size = .1cm, thick, draw =black!80, node distance = 3mm},
         connect/.style={-latex, thick},
         box/.style={rectangle, draw=black}
}
\begin{document}
  \begin{tikzpicture}[lds/.pic={j=#1,colr=#2,%<----- here is the variable
      \node[box,draw=\colr] (-Latent) {};
      \node[main,minimum size=.2cm, right=of -Latent] (-L1) {$x_1^{(\j)}$};
      \node[main,minimum size=.2cm] (-L2) [right=of -L1] {$x_2^{(\j)}$};
      \node[main,minimum size=.2cm] (-Lt) [right=5mm of -L2] {$x_T^{(\j)}$};
      \node[box,draw=white!100] (-Observed) [below=of -Latent] {};
      \node[main,fill=black,text=white,minimum size=.2cm] (-O1) [right=of -Observed,below=of -L1] {$y_1^{(\j)}$};
      \node[main,fill=black,text=white,minimum size=.2cm] (-O2) [right=of -O1,below=of -L2] {$y_2^{(\j)}$};
      \node[main,fill=black,text=white,minimum size=.2cm] (-Ot) [right=of -O2,below=of -Lt] {$y_T^{(\j)}$};
      \draw (-L1.east) edge [connect] (-L2);
      \node at (16,0) {$\dots$};
      \path (-L1.south) edge [connect] (-O1);
      \path (-L2.south) edge [connect] (-O2);
      \path (-Lt.south) edge [connect] (-Ot);
           },my text/.style={rounded corners=2pt, text width=10mm,     font=\sffamily, line width=.5pt, align=left},
      my arrow/.style={rounded corners=2pt, draw=green!15, line width=1.5mm, -{Triangle[]}}]
    \pgfmathsetmacro\j{6} 
    \def\colr{white} %<----here
    \pic(lds1) at (0,7){lds};
  \end{tikzpicture}
\end{document}

Best Answer

I don't know if the syntax you use at the beginning of the pic lds definition is legal, I never saw it like that, but my guess is that it is illegal. When you write j=#1,colr=#2 my guess is that those tokens are simply ignored by tikz (unless it is a kind of key-value syntax I'm not aware of).

Later, in your "main" tikz code you define \j, and this is the reason why when you use \j later in your code it works, but the assignment j=#1 has nothing to do with it. For the same reason, \def\colr in the "main" part of the figure should work too (in my test, it worked).

However, I think the correct syntax for passing several values to a pic (as explained for example in this answer is as follows:

\tikzset{
 pics/lds/.style 2 args={code={
 % ... here #1 and #2 can be used
 % ...
 }}
}

In your code, you should use #1 instead of \j and #2 instead of \colr. But also, if you prefer not changing your code, you can start the definition of lds pic as follows:

\tikzset{
 pics/lds/.style 2 args={code={
  \pgfmathsetmacro\j{#1}
  \def\colr{#2}
  % The remaining code is untouched
 }}

Later, to use this pic, you write: \pic(lds1) at (0,7) {lds={6}{white}};.

Complete code:

\tikzset{
main/.style={circle, minimum size = .1cm, thick, draw =black!80, node distance = 3mm},
connect/.style={-latex, thick},
box/.style={rectangle, draw=black},
pics/lds/.style 2 args={code={
      \pgfmathsetmacro\j{#1}
      \def\colr{#2}%<----- here is the variable
      \node[box,draw=\colr] (-Latent) {};
      \node[main,minimum size=.2cm, right=of -Latent] (-L1) {$x_1^{(\j)}$};
      \node[main,minimum size=.2cm] (-L2) [right=of -L1] {$x_2^{(\j)}$};
      \node[main,minimum size=.2cm] (-Lt) [right=5mm of -L2] {$x_T^{(\j)}$};
      \node[box,draw=white!100] (-Observed) [below=of -Latent] {};
      \node[main,fill=black,text=white,minimum size=.2cm] (-O1) [right=of -Observed,below=of -L1] {$y_1^{(\j)}$};
      \node[main,fill=black,text=white,minimum size=.2cm] (-O2) [right=of -O1,below=of -L2] {$y_2^{(\j)}$};
      \node[main,fill=black,text=white,minimum size=.2cm] (-Ot) [right=of -O2,below=of -Lt] {$y_T^{(\j)}$};
      \draw (-L1.east) edge [connect] (-L2);
      \node at (16,0) {$\dots$};
      \path (-L1.south) edge [connect] (-O1);
      \path (-L2.south) edge [connect] (-O2);
      \path (-Lt.south) edge [connect] (-Ot);
           }},
%my text/.style={rounded corners=2pt, text width=10mm,font=\sffamily, line width=.5pt, align=left},
%my arrow/.style={rounded corners=2pt, draw=green!15, line width=1.5mm, -{Triangle[]}}      
}

  \begin{tikzpicture}[]
    \pic(lds1) at (0,7) {lds={6}{white}};
  \end{tikzpicture}

Result:

In addition, I would prefer to use \colorlet instead of \def when definig colors. This means to change \def\colr{#2} by \colorlet{colr}{#2}, and then, when the color is needed, write it with the same syntax than any of the predefined colors, i.e., for example draw=colr instead of draw=\colr.

This way you can define "mixings" based on the color received in #2, as for example: \colorlet{myforeground}{#2!30!white}, \colorlet{mybackground}{#2!30!black}.

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[Tex/LaTex] How to define the default vertical distance between nodes

I don't really get the question so I hope this is what you wanted. If you include a full document (such that we copy paste and see the problem on our systems) things are much more easier.

Here, you can change the default setting within a scope but your block style had a node distance which was resetting every time it is issued. I've made it 2mm such that we can see the difference easier.

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows,shapes.geometric,positioning}

\begin{document}
\begin{tikzpicture}[decision/.style={diamond, draw, text width=4.5em, text badly centered, node distance=3.5cm, inner sep=0pt},
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\end{scope}
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enter image description here

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

A solution which allows to draw intersection segments of any two intersections is available as tikz library fillbetween.

This library works as general purpose tikz library, but it is shipped with pgfplots and you need to load pgfplots in order to make it work:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}];

\end{tikzpicture}

\end{document}

enter image description here

The key intersection segments is described in all detail in the pgfplots reference manual section "5.6.6 Intersection Segment Recombination"; the key idea in this case is to

create a temporary path temp1 which is the first intersection segment of red and blue, more precisely, it is the first intersection segment in the Left argument in red and blue : red. This path is drawn as thin black path. Substitute its \draw statement by \path to make it invisible.
Compute the desired intersection segment by intersecting temp1 and green and use the correct intersection segment. By trial and error I figured that it is the third segment of path temp1 which is written as L3 (L = left argument in temp1 and green and 3 means third segment of that path).

The argument involves some trial and error because fillbetween is unaware of the fact that end and startpoint are connected -- and we as end users do not see start and end point.

Note that you can connect these path segments with other paths. If such an intersection segment should be the continuation of another path, use -- as before the first argument in sequence. This allows to fill paths segments:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,fill=blue,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}]  
    [intersection segments={of=temp1 and green, sequence={--R2}}]
;

\end{tikzpicture}

\end{document}

enter image description here

Best Answer

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[Tex/LaTex] How to define the default vertical distance between nodes

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

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