# Clashing multirow with tikz

In order to get a diagonal line in a cell, I picked up a piece of code from Diagonal lines in table cell

The code adapted to my situation works fine until I decide to use multirow.

Here is the MWE.

\documentclass{article}

\usepackage{multirow}

\usepackage{tikz}
\newcommand\diag[4]{%
\multicolumn{1}{p{#2}|}{\hskip-\tabcolsep
$\vcenter{\begin{tikzpicture}[baseline=0,anchor=south west,inner sep=#1] \path[use as bounding box] (0,0) rectangle (#2+2\tabcolsep,\baselineskip); \node[minimum width={#2+2\tabcolsep},minimum height=\baselineskip+\extrarowheight] (box) {}; \draw (box.north west) -- (box.south east); \node[anchor=south west] at (box.south west) {#3}; \node[anchor=north east] at (box.north east) {#4}; \end{tikzpicture}}$\hskip-\tabcolsep}}

\begin{document}

\begin{tabular}[t]{|c|c|c|}
\hline
\multirow{2}{*}{\diag{.1em}{.5cm}{$a$}{$i$}}&\multicolumn{2}{c|}{A}\\\cline{2-2}
&1\\
\end{tabular}

\end{document}


This produces an error message,

 ! Misplaced \omit. \multispan ->\omit
\@multispan  l.20 ...ultirow{2}{*}{\diag{.1em}{.5cm}{$a$}{$i$}}
&\multicolumn{2}{c|}{A}\\\...


If I omit the \multirow part this works fine.

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Use of diagbox was found to be a better option. This also did not clash with multirow. – Masroor Jun 3 '13 at 7:39
The problem here lies in using a multicolumn inside a multirow. This asks for all kinds of problems, prompting the "Misplaced \omit" error. – Heinrich Jul 30 '13 at 13:49

As noted in comments you can't use \multicolumn here however as it is only spanning 1 cell, you don't need \multicolum and can simply use a \parbox.

The picture was generating a 12pt overfull box warning as 2\tabcolsep was accounted for twice so I removed the inner addition of this ammount.

The A was in a multicolumn{2} so I put the 1 in to match, otherwise things didn't line up.

The code needed array package adding as you'd used \extrarowheight which is defined by that package.

\documentclass{article}

\usepackage{multirow,array}

\usepackage{tikz}
\newcommand\diag[4]{%
%  \multicolumn{1}{p{#2}|}
\parbox[t]{#2}%
{\hskip-\tabcolsep
$\vcenter{\begin{tikzpicture}[baseline=0,anchor=south west,inner sep=#1] \path[use as bounding box] (0,0) rectangle (#2,\baselineskip); \node[minimum width={#2+2\tabcolsep},minimum height=\baselineskip+\extrarowheight] (box) {}; \draw (box.north west) -- (box.south east); \node[anchor=south west] at (box.south west) {#3}; \node[anchor=north east] at (box.north east) {#4}; \end{tikzpicture}}$\hskip-\tabcolsep}}

\begin{document}

\begin{tabular}[t]{|c|c|c|}
\hline
\multirow{2}{*}{\diag{.1em}{.5cm}{$a$}{$i$}}&\multicolumn{2}{c|}{A}\\\cline{2-3}
&\multicolumn{2}{c|}{1}\\
\end{tabular}

\end{document}

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