# tikz, modify code for drawing DNA sequence

I need to modify how to draw DNA sequences. There is a function \DNASequence which does the job. It uses nodes of constant size. However, I need to put arbitrary text instead of only one letter in a cell. How to do it? I tried to modify original code but I don't know how to get the actual width of a node.

\documentclass[10pt]{beamer}
\usepackage[utf8]{inputenc} % Language = Spanish
\usepackage{color}
\usepackage{tikz}
\usetheme{Warsaw}
\usecolortheme{whale}
\usepackage{xstring}
\usetikzlibrary{calc, arrows}

\newcommand*{\NodeSize}{0.5cm}%
\newcommand*{\YShiftBetweenRows}{-1cm}% Subsequent rows are shited down so they don't overlap
\tikzset{DNA Style/.style={minimum size=0.5cm, draw=gray, line width=1pt}}{}

\newlength{\YShift}%
\newcounter{ColumnCounter}% Prefix for node labels

\setlength{\YShift}{0cm}%
\setcounter{ColumnCounter}{0}
\newcounter{angle}
\setcounter{angle}{0}
%
\begin{document}
\newcommand*{\DNASequence}[2][Mark]{%
% http://tex.stackexchange.com/questions/12091/tikz-foreach-loop-with-macro-defined-list
\def\Sequence{#2}
\foreach [count=\xi] \Label/\Color in \Sequence {%
\pgfmathsetmacro{\XShift}{\NodeSize*\xi}%
\IfStrEq{\Color}{}{\def\Color{white}}{}
\edef\NodeName{#1-\arabic{ColumnCounter}}
\node [DNA Style, fill=\Color, xshift=\XShift] (\NodeName) {\Label};
\stepcounter{ColumnCounter}
}
}%

\begin{frame}{bla}
\begin{tikzpicture}
\DNASequence{AAAA/cyan,, Big/orange,,,Small/blue,,G/red!25,,C/yellow};
\end{tikzpicture}
\end{frame}
\end{document}


EDIT: I need \DNASequence function which draws arbitrary text in the nodes.

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Please add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. –  Jubobs May 6 '13 at 7:30

The following is adapted from my earlier answer at Display issues drawing DNA sequences with TikZ:

## Code:

\documentclass[border=3pt]{article}
\usepackage{tikz}
\usepackage{xstring,calc}
\usetikzlibrary{calc}

\newlength{\NodeSize}

\tikzset{DNA Style/.style={minimum size=0.5cm, draw=gray, line width=1pt, inner sep = 2pt}}{}

\newcounter{ColumnCounter}% Prefix for node labels

\newlength{\CurrentXPos}
\newcommand*{\PreviousNode}{}%
\newcommand*{\DNASequence}[2][Mark]{%
% http://tex.stackexchange.com/questions/12091/tikz-foreach-loop-with-macro-defined-list
\def\Sequence{#2}%
\def\PreviousNode{}%
\foreach [count=\xi] \Label/\Color in \Sequence {%
\IfStrEq{\Color}{}{\def\Color{white}}{}
\edef\NodeName{#1-\arabic{ColumnCounter}}
\IfStrEq{\PreviousNode}{}{%
\node [DNA Style, fill=\Color, anchor=west] (\NodeName) {\Label};
\xdef\PreviousNode{\NodeName}%
}{
\node [DNA Style, fill=\Color, anchor=west, xshift=-\pgflinewidth] at (\PreviousNode.east)(\NodeName) {\Label};
\xdef\PreviousNode{\NodeName}%
}
\stepcounter{ColumnCounter}
}
}%

\begin{document}
\begin{tikzpicture}
\begin{scope}
\DNASequence{ABCC/magenta!20,,, XYZ/violet!30,,ABC/green, G/blue!20,, G/cyan!30,, C/olive};
\end{scope}
\begin{scope}[yshift=-1cm]
\DNASequence{ABCDEFGHS/brown!20,, XYS/cyan!30,,, G/blue!20,, G/orange!30,, C/blue!30, X/red!20, Y/yellow!75};
\end{scope}
\end{tikzpicture}
\end{document}

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NOOO, If you put many letters instead of one letter then everything shifts. –  ashim May 6 '13 at 7:39
@msh: Have adapted it for your requirements... –  Peter Grill May 6 '13 at 8:00
Thanks! that is amazing! really =) –  ashim May 6 '13 at 8:03