heading breaks with twopage option for book class

Question

I had to switch from oneside to twoside option for book class to get the binding right. Unfortunately this breaks the chapter headings if they land on even pages (on uneven pages the heading looks fine).

Any idea how I adjust the heading so it accounts for the dynamic nature of the twopage option?

% using fncychap style Bjarne...

% Adding a tiny robot
\let\oldDOCH\DOCH

\makeatletter
\renewcommand\DOCH{%
    \mghrulefill{\RW}\par\nobreak
    \begin{tikzpicture}[remember picture, overlay]
        \node [xshift=1.05in, yshift=-1.43in] (robot) at (current page.north west)
          {\includegraphics[width=89px,height=130px]{tiny_robot.png}};
        \node[left] at ($(robot) + (5.71in,0.04in)$) {
          \CNV\FmN{\@chapapp}\space \CNoV\thechapter\par\nobreak};
        \draw[very thick] ($(robot) + (-0.10in,-0.20in)$) -- +(5.75in,0in);
    \end{tikzpicture}
    \par\nobreak
    \vskip 30\p@
}
\makeatother

Answer 1

after some experiments I realized that the "absolute" positioning caused the problem. Now I use "relative" positioning and it works fine.

\makeatletter
\renewcommand\DOCH{%
    \mghrulefill{\RW}\par\nobreak
    \begin{tikzpicture}[remember picture, overlay]
        \node [xshift=0.10in, yshift=0.03in] (robot)
          {\includegraphics[width=89px,height=130px]{tiny_robot.png}};
        \node[left] at ($(robot) + (5.70in,0.04in)$) {
          \CNV\FmN{\@chapapp}\space \CNoV\thechapter\par\nobreak};
        \draw[very thick] ($(robot) + (-0.10in,-0.20in)$) -- +(5.75in,0in);
    \end{tikzpicture}
    \par\nobreak
    \vskip 30\p@
}
\makeatother