This is caused by a bug in the current version of adjustbox. The trim values are evaluated before the \width macro is set. I fixed this in the package and the next released version will work fine with the given code.
As cmhughes pointed out you can actually use the custom width \mywidth here because it is also used to determine the to-be-adjusted content. So instead of:
\adjustbox{trim=0 0 {.5\width} 0,clip}{\includegraphics[width=2\mywidth]{#3}}
%...
\adjustbox{trim={.5\width} 0 0 0,clip}{\includegraphics[width=2\mywidth]{#3}}
you can write:
\adjustbox{trim=0 0 {\mywidth} 0,clip}{\includegraphics[width=2\mywidth]{#3}}
%...
\adjustbox{trim={\mywidth} 0 0 0,clip}{\includegraphics[width=2\mywidth]{#3}}
which will work with the current buggy version as well.
I used \adjustbox (which is somewhat based on the graphicx code) around the \includegraphics macro because we need to resize first and then clip. Unfortunately \includegraphics doesn't provide a \width macro to clip relative to the original width.
However I added some new features to adjustbox since I wrote the original code and so you can write it as well in the following form when the adjustbox package is loaded with the export option:
\includegraphics[width=2\mywidth,Clip=0 0 {.5\width} 0]{#3}}%
%...
\includegraphics[width=2\mywidth,Clip={.5\width} 0 0 0]{#3}}%
which works because Clip is handled differently than clip,trim=..., or:
\includegraphics[width=2\mywidth,Clip=0 0 {\mywidth} 0]{#3}}%
%...
\includegraphics[width=2\mywidth,Clip={\mywidth} 0 0 0]{#3}}%
Odd numbered pages should always be right pages!
So you should always use \cleardoublepage before changing page numbering, because it makes no sense to change page numbering on the left side of a double sided print:
\documentclass[twoside]{article}% It's better to tell already the class to use twoside!
\usepackage[showframe]{geometry}
\begin{document}
This is the first page; it should be a right page (recto).
\cleardoublepage
\pagenumbering{arabic}
This is the third page; it should be a right page, because changing page numbering should always be done on right pages!
\end{document}
If you simply wanted to suppress page number at the first page of an article, try:
\documentclass[twoside]{article}% It's better to tell already the class to use twoside!
\usepackage[showframe]{geometry}
\begin{document}
\title{Title}
\author{Me}
\maketitle\thispagestyle{empty}
\begin{abstract}A short abstract of the document.\end{abstract}
Some more text, e.g. a table of contents.
\clearpage
This is the second page; it should be a left page and numbered 2!
\end{document}
Note: You may use \cleardoublepage before \pagenumbering even at oneside documents, because in this case it would have the same result \clearpage would have.
But, if you really, really must have odd pages left and even pages right, you may simply switch the margins (and the margin used for \marginpar):
\documentclass[twoside]{article}% It's better to tell already the class to use twoside!
\usepackage[showframe]{geometry}
\makeatletter
\newcommand*{\flipmargins}{%
\clearpage
\setlength{\@tempdima}{\oddsidemargin}%
\setlength{\oddsidemargin}{\evensidemargin}%
\setlength{\evensidemargin}{\@tempdima}%
\if@reversemargin
\normalmarginpar
\else
\reversemarginpar
\fi
}
\makeatother
\begin{document}
This is the first page; it should be a right page (recto).
\flipmargins
\pagenumbering{roman}
This is the second page; it should be a left page (verso).
\end{document}
Using a page style like headings you may also need to change the page style, e.g., to print the numbers near the outer margin. You may do this, using either scrpage2 or fancyhrd. Here an example using scrpage2:
\documentclass[twoside]{article}% It's better to tell already the class to use twoside!
\usepackage[showframe]{geometry}
\usepackage[automark]{scrpage2}
\pagestyle{scrheadings}
\makeatletter
\newcommand*{\flipmargins}{%
\clearpage
\setlength{\@tempdima}{\oddsidemargin}%
\setlength{\oddsidemargin}{\evensidemargin}%
\setlength{\evensidemargin}{\@tempdima}%
\if@reversemargin
\normalmarginpar
\else
\reversemarginpar
\fi
\ifdim \evensidemargin>\oddsidemargin
\ihead{\headmark}%
\ohead[\pagemark]{\pagemark}%
\else
\ihead[\pagemark]{\pagemark}%
\ohead{\headmark}%
\fi
}
\makeatother
\begin{document}
\section{Normal pages}
This is the first page; it should be a right page (recto).
\flipmargins
\pagenumbering{roman}
\section{Inverse margin pages}
This is the second page; it should be a left page (verso).
\end{document}
Alternative:
One completely different alternative would be to fake the page number, given by \thepage:
\documentclass[twoside]{article}% It's better to tell already the class to use twoside!
\usepackage[showframe]{geometry}
\makeatletter
\newcommand{\@arabicplusone}[1]{\@arabic{\numexpr #1+1\relax}}
\newcommand{\@romanplusone}[1]{\@roman{\numexpr #1+1\relax}}
\newcommand{\@Romanplusone}[1]{\@Roman{\numexpr #1+1\relax}}
\newcommand{\@alphplusone}[1]{\@alph{\numexpr #1+1\relax}}
\newcommand{\@Alphplusone}[1]{\@Alph{\numexpr #1+1\relax}}
\makeatother
\newcommand*{\pagenumberingplusone}[1]{%
\pagenumbering{#1plusone}\setcounter{page}{0}%
}
\begin{document}
This is the first page; it should be a right page (recto). See
page~\pageref{test}.
\clearpage\pagenumberingplusone{roman}
This\label{test} is the second page; it should be a left page (verso).
\end{document}
Disadvantage of this suggestion would be, that if a package uses page counter directly for something else but testing odd or even the result may be unexpected. The advantage of this suggestion would be, that pages with odd value of counter page shows not only an even page number but will be handled to be a even=left page by LaTeX and every class or package that uses \c@page or \value{page} for the test (and vica versa).
Best Answer
You can use the
figure*ortable*environments (the contents will appear in the top of the next page where you write it); those environments can be used to typeset material that span both columns: