You can use QuaZIP. It’s a wrapper for zlib.

There is a FAQ entry on compression and decompression.

I can’t uncompress svgz with quazip or qzipreader.
I can uncompress only usual zip files.

Only way I find, is to rename svgz to gz.
And then:

You can start a QProcess using “gunzip -c”, then feed the compressed svgz to the process’ stdin (using QProcess::write!) and read the decompressed data from the process’ stdout (using QProcess::read!). As QProcess is a QIODevice, you might try to attach a QTextStream to it for reading.

:)
So, Qt can’t read svgz.
I’ll try to use method proposed by Volker.
Thanks.

It was easier than I thought:

You’re welcome. You might try

Maybe that saves you from copying around some bytes in the QByteArray.

Thanks a lot. Again. :)
I didn’t know about this method.

In Qt, many classes that deal with data have a constructor or method that uses a QIODevice pointer as data source. It’s always worth a try to look for those.