Using macros in \DeclareGraphicsRule statement using shell command

Question

I am currently working on a document which i am compiling under both linux and windows. As one of the images I use is a tif image, I'd like to have lualatex converting it on-runtime to a format it understands.

Therefore, I managed to do this under linux using

\DeclareGraphicsRule{.tif}{png}{.png}%
{%
  `convert #1 `dirname #1`/`basename #1 .tif`-tif-converted-to.png %
}
\AppendGraphicsExtensions{.tif}

This however is not portable to windows because of the dirname and basename commands (as installing ImageMagick makes convert available).

Therefore, I would like to use the file parsing from latex to do this, but I could not find my way around it. The code I am currently trying to use is :

\makeatletter
\newrobustcmd*\dirname[1]{\filename@parse{#1}\filename@area}%
\newrobustcmd*\basename[1]{\filename@parse{#1}\filename@base}%
\DeclareGraphicsRule{.tif}{png}{.png}%
{%
  `convert #1 \dirname{#1}/\basename{#1}-tif-converted-to.png %
}%
\makeatother
\AppendGraphicsExtensions{.tif}

However, \DeclareGraphicsRule seems to just ignore I have used macros in my command.

So my question is the following :

• What am I doing wrong ?
• Is there a way around it ?

EDIT : Slightly changing the working command

Answer 1

The conversion via shell escape is added by package epstopdf. In TeX Live it is automatically loaded, if pdfTeX/LuaTeX is detected in PDF mode and

1. LaTeX is running (plain TeX users are on their own),
2. and shell escape (\write18) is enabled (possibly restricted),
3. and \DoNotLoadEpstopdf either does not exist or is not \relax.

For convenience the package epstopdf provides a macro to define a graphics rule with conversion program (1.5.3 Conversion program):

\epstopdfDeclareGraphicsRule{.tif}{png}{.png}{%
  convert #1 \OutputFile         
}

Also the backtick notation with \DeclareGraphicsRule can be used:

\DeclareGraphicsRule{.tif}{png}{.png}{%
  \noexpand\epstopdfcall{convert #1 \noexpand\OutputFile}%
}

• \noexpand is needd, because \DeclareGraphicsRule expands the argument.
• \epstopdfcall deals with packages like pst2pdf.

The name of the output file \OutputFile is controlled by options. Since version 2009/07/12 v2.0 the default for option suffix is

suffix=-\SourceExt-converted-to

The suffix is inserted after the base name and the new file extension. foo.tif becomes foo-tif-converted-to.png.

Answer 2

Macros defined with \newrobustcmd (from etoolbox) are not expanded in \write operations. However \filename@parse relies on assignments which aren't performed in those operations.

I suggest to define

\def\eattif#1.tif{#1}
\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 \eattif#1-tif-converted-to.png }
\AppendGraphicsExtensions{.tif}

so that the extension will be swallowed (in an expandable fashion).