3

I am trying to include an image in my document:

\documentclass[a4paper,10pt,twoside]{book}
\usepackage{graphicx}

\begin{document}

\def\foo{scale=0.1}
\includegraphics[\foo]{fig1.eps}

\end{document}

gives me the error

ERROR: Package xkeyval Error: `scale=0.1' undefined in families `Gin'.

It has something to do with macro expansion, but I was not able to solve it. Then I saw this question with the following answer

Defining a private \includegraphics allows you to call macros as optional arguments:

\protected\def\newincludegraphics{\@testopt\new@includegraphics{}}
\def\new@includegraphics[#1]{%
  \begingroup
  \@protected@edef\x{\endgroup
    \noexpand\includegraphics
    \if\relax\detokenize{#1}\relax\else[#1]\fi
   }\x
}

\newincludegraphics[\scalefactor]{image}

where the new macro \newincludegraphics was defined.

MWE

\documentclass[a4paper,10pt,twoside]{book}
\usepackage{graphicx}

\begin{document}
\protected\def\newincludegraphics{\@testopt\new@includegraphics{}}
\def\new@includegraphics[#1]{%
  \begingroup
  \@protected@edef\x{\endgroup
    \noexpand\includegraphics
    \if\relax\detokenize{#1}\relax\else[#1]\fi
   }\x
}

\def\foo{scale=0.1}
\newincludegraphics[\foo]{fig1.eps}

\end{document}

Nevertheless I still get this error:

ERROR: You can't use `\spacefactor' in vertical mode.

--- TeX said ---
\@->\spacefactor 
                 \@m 
l.62 \newincludegraphics
                        [scale=0.1]{fig1.eps}

What could be the cause of this error, and is there a workaround without defining another macro to include graphics?

Community
  • 1
osolmaz
  • 1,283
  • You need \makeatletter just before your new command due to the @ letter –  Jul 06 '14 at 09:49
  • rather than \def\foo{scale=0.1} the intended usage is that you use \setkeys{Gin}{scale=0.1} ... \includegraphics{fg1} – David Carlisle Jul 06 '14 at 09:50
  • @DavidCarlisle I am changing the scale this way, but for some reason it doesn't have an effect. – osolmaz Jul 06 '14 at 10:01
  • @ChristianHupfer I tried every combination of \makeatletter and \makeatother but cannot seem to make it work, would you care to post an answer? – osolmaz Jul 06 '14 at 10:07
  • 2
    oops:-) http://tex.stackexchange.com/questions/164116/which-arguments-of-includegraphics-cannot-be-set-beforehand/164132#164132 – David Carlisle Jul 06 '14 at 10:11
  • @DavidCarlisle but does that make a global change? In that case, I only want to change the scale for that figure. What is the most elegant option here? – osolmaz Jul 06 '14 at 10:13
  • possible as you had it originally but \expandafter\includegraphics\expandafter[\foo]{fig1.eps} ro expand \foo first. – David Carlisle Jul 06 '14 at 10:17
  • Indeed, I was trying to use that without success till I realized the problem was with a new line (literally, not \newline) I put in a macro after \edef. So this solved my problem: http://tex.stackexchange.com/questions/7453/what-is-the-use-of-percent-signs-at-the-end-of-lines – osolmaz Jul 06 '14 at 11:23
  • @DavidCarlisle If you can post \expandafter\includegraphics\expandafter[\foo]{fig1.eps} as an answer, I can mark it. But I also think this question might be a duplicate. – osolmaz Jul 06 '14 at 11:24

2 Answers2

5

the keyval parser does not expand macros, but you can do

\expandafter\includegraphics\expandafter[\foo]{fig1.eps}

to expand \foo first if you need to.

David Carlisle
  • 757,742
4

You can define a new key:

\documentclass[a4paper,10pt,twoside]{book}
\usepackage{graphicx}

\makeatletter
\define@key{Gin}{foo}[]{\setkeys{Gin}{scale=0.1}}
\makeatother

\begin{document}

\includegraphics[foo]{example-image.pdf}

\end{document}

The second argument to \setkeys is not expanded, and the optional argument to \includegraphics like in

\includegraphics[<whatever>]{file}

is basically managed as \setkey{Gin}{<whatever>}.

egreg
  • 1,121,712