# Create WOFF files with Zopfli compression
This is a modified version of the [sfnt2woff utility](https://people.mozilla.org/~jkew/woff/) that uses Zopfli as a compression algorithm instead of zlib. This results in compression gains of — on average — 5-8% compared to regular WOFF files. Zopfli generates compressed output that is compatible with regular zlib compression so the resulting WOFF files can be used everywhere.
##Usage
To create a WOFF file from an OpenType files:
> sfnt2woff-zopfli [-v <maj>.<min>] [-m <metadata.xml>] [-n <iterations>] [-p <private.dat>] <otffile>
Options:
-v <maj>.<min> set font version number (major and minor, both integers)
-m <metadata.xml> include metadata from <metadata.xml> (not validated)
-n <iterations> number of zopfli iterations (default = 15)
-p <private.dat> include private data block
To decompress a WOFF file and write the OpenType file to stdout:
> woff2sfnt-zopfli [-v | -m | -p] <woff>
Options:
-v write font version to stdout
-m write WOFF metadata block to stdout
-p write private data block to stdout
## Compiling
To compile the utilities, run make:
> make
This will compile two utilities `sfnt2woff-zopfli` to convert OpenType files to WOFF and `woff2sfnt-zopfli` to convert WOFF files back to OpenType files. If the build was succesful you can make them available on your system by copying the resulting executables to `/usr/local/bin` and making them executable (`chmod 755`).
## Licensing
The WOFF portion of the code is taken from [sfnt2woff](https://people.mozilla.org/~jkew/woff/), which is licensed under the MPL/GPL/LGPL. The [Zopfli implementation](https://code.google.com/p/zopfli/) is licensed under the Apache License. My modifications to `woff.c` are also licensed under the MPL/GPL/LGPL.
## Alternative
You can also use the [ttf2woff tool](http://wizard.ae.krakow.pl/~jb/ttf2woff/), which also converts OpenType files to WOFF using Zopfli, but is exclusively licensed under the GPL. However it doesn't have a command line option for the number of Zopfli iterations and thus can't create files as small as sfnt2woff-zopfli.