LXer Feature: 24-May-2013 Recently I've been trying to 'minimize' some big 'legacy' MS Word files. When using MS Office to export to HTML (unfiltered), I've found out they're so big because they have EMZ (gzipped EMF) and WMZ (gzipped WMF) files in them, accompanied by large "msoledata-thingies". These WMZ's / EMZ's are (zipped) "container" formats, and some of them contain vector graphics, a bit like SVG - but sadly Microsoft doesn't seem to support SVG in MS Office. These EMF / WMG-graphics may contain vector images: That's text, fonts and lines - which has to remain readable of course. I found out replacing this EMZ / WMZ files by PNG files in the Word-documents dramatically reduces size.

Though EMF is a pretty open file format, documentation is available here, EMZ / WMZ files cannot be used cross-platform without hassle, because basically they contain programming instructions for Windows' Graphics Device Interface (GDI). There is a Linux-port of GDI made in Mono, which might help. However, 'transcoding' the GDI-instructions to a more broadly supported graphics format such as PNG or SVG which doesn't need Microsoft-specific code to render may be a good thing, it's a way of "liberating" your graphics from being dependent on the Windows GDI. However, it's only a good idea depending on what you need: You have to manually check your "converted" files if they're what you want. Please remember that converting from a "vector-format" like EMF may be to a "raster format" like PNG will not be lossles.

Because this has to be done at my current job, I have to use Windows 7. So, I want to use preferably portable free software. I want to batch-convert these files to PNG, preferably with a resolution of 300 DPI, as that will probably lead to readable results - even if printed.

Sadly, after trying a lot, it seems no solution can handle all EMF / WMF files with a batch-script: Some applications can do the raster-files but not the vector files, while some others can do the vector files but not the raster files. Some do all, but everything with low resolution leading to bad quality and unreadable texts.

Lacking solutions:

MS Office

MS Paint

GIMP

ImageMagick

UNOConv

Inkscape

VeryPDF

The script I tried

mkdir convert
cp *.emz convert
cp *.wmz convert
cd convert
for i in *.wmz; do mv ${i} ${i/wmz/wmf.gz}; done
for i in *.emz; do mv ${i} ${i/emz/emf.gz}; done
rm *.wmz
rm *.emz
gunzip *.gz
for i in *.emf; do Inkscape.exe -f C:/$(pwd)/${i} -d 300  -e C:/$(pwd)/${i/emf/png}; done
for i in *.wmf; do Inkscape.exe -f C:/$(pwd)/${i} -d 300  -e C:/$(pwd)/${i/wmf/png}; done
mkdir new
mv *.png new
rm image*
mv new/* .
rmdir new

$ convert C:/$(pwd)/${i} C:/$(pwd)/${i/emf/png}

Related StackOverflow questions

Special thanks

Conclusion