I did some work with PDF output. Mainly I refactored some of the output generation code to reduce redundant sections. Over all there won’t be any user visible changes.
The main reason I dove back into PDF output was because a user on OS X noted that PDF produced were not searchable. Windows users are getting searchable PDFs and on Kovid’s Gentoo Linux machine he was able to get a searchable PDF. I looked into the issue and cannot get searchable PDFs on OS X. However, I can get searchable PDFs when using the ebook-viewers print feature via print to file. I’m not sure why this happens because the ebook-viewer and PDF output use the same technique for generating a PDF. I’ve decided not to peruse the matter further because PDF output on OS X is pretty much broken due to Qt bugs. See this for an example.
TCR compression was something I added a while ago. I was never fully happy with it because it was slow, and produced low quality output. I spent a few days completely rewriting the compressor and now it performs beautifully. The new compressor is cleaner, an order of 10x faster, compresses to a much smaller size, and I would say is on par with the output of Andrew Giddings' TCR implementation. However, calibre’s TCR compressor is a pure python implementation is still considerably slower than Andrew’s C implementation.
A minor bug in FB2 output was brought to my attention and fixed. Basically JPG images in the input document were not being written to the FB2 output file. This has been corrected.