Looking into a document having images with WinZip, it appears that GIF and PNG files are not compressed and SVM files are (with great improvement). The content.xml files, which can be megabytes long, benefit greatly from compression (9:1 easily).
Apache OpenOffice 3.4.1 and older versions of OpenOffice.org will compress the Thumbnail PNG. Not sure why, but it is a small file so it shouldn't matter in terms of Save performance. - Dennis PS: I don't know whether uncompressed results are also obtained by attempting compression and reverting to STORED when the compression is unsuccessful. Some software does that sort of thing. (I have a recollection that DEFLATE can also produce uncompressed sections on discovery of their uncompressability, but the result won't be the same size as the original. I don't know if the DEFLATE compression used will produce those.) -----Original Message----- From: Rob Weir [mailto:robw...@apache.org] Sent: Monday, June 10, 2013 05:45 AM To: users@openoffice.apache.org; Dennis Hamilton Subject: Re: [DISCUSS] ODF file formats vs Zip On Sun, Jun 9, 2013 at 4:01 PM, Dennis E. Hamilton <dennis.hamil...@acm.org> wrote: > Regina is correct about the only two compressions. As far as I know, there > is no way to control which compression is used. (If you save with Password, > all files are always compressed.) Most of the time DEFLATE is used (although > there are two files that are not usually compressed, apparently to make > metadata mining simpler for non-encrypted packages). > > There is currently no way to control the compression in AOO. (The ODF > specification simply stipulates the compression that must be used when > compression is done, not whether compression is done for parts of unencrypted > packages.) > Does anyone know whether AOO is smart enough to not waste time trying to compress already compressed files, like PNG images? This could make a big difference in presentations. -Rob [ ... ] --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@openoffice.apache.org For additional commands, e-mail: users-h...@openoffice.apache.org
