Am 25.05.2011 21:54, schrieb Hartmut Henkel: > On Wed, 25 May 2011, Hans Hagen wrote: >> On 25-5-2011 2:43, Peter Rolf wrote: >>> >>> I just made a one pager (TEXpage) out of a big png graphic >>> (5900x4094). The compressed size of the graphics is normally around >>> 1.37MB on the highest png compress level (9) and 1.32MB after using >>> optipng (only around 3% reduction this time). To my surprise the >>> size of the final PDF was about 2.3MB. After adding >>> '\pdfcompresslevel9' the size went down to 1.48MB. Still not what I >>> wanted... >>> >>> So I was wondering: is there an option to embed the png graphic as >>> it is (no re-compression)? > > no. There is a "PNG Copy" function for literal embedding of the PNG > file, but that triggers only, if the file simultaneously satisfies quite > a few conditions, which are about: non-interlaced, no palette, no > transparency, no gamma coming with it, no gamma modification requested, > no white adjustment in the PNG, and a few more rare others. Else it's > de-compressed and then re-compressed to the \pdfcompresslevel, and > additional streams and dicts are added. You see in the log if it finally > was "PNG Copy" or not. > Sigh, most of my graphics use (and need) transparency. So the only advantage I get from optipng is the smaller file size on my disk. Sad, but good to know. ;-)
> Preprocessing the PNG, e. g., by convert, sometimes changes it that it > gets copyable. Obviously flattening transparency also helps. > > Anyway direct embedding or not can have positive or negative influence > on the PDF file size. E. g. if a PNG is copied verbatim, and it contains > lots of meta-data info, the PDF file will probably get larger, since > normal PNG embedding removes all these info chunks. > And what about icc profiles? > Another factor influencing the size is if it's PDF-1.4 or PDF-1.5: If > you have a 16 bit PNG, for PDF-1.4 it will be automatically reduced to 8 > bit by luatex and pdftex, so suddenly the PDF file gets smaller, but > actually also the image quality (silently) went down. > > These are about the factors affecting the PNG to PDF size. For your big > PNG graphic you may find a preprocessing (e. g., pngtopnm | pnmtopng > will definitely remove all fat) that makes it compliant with the "PNG > copy". > I will give that a try. But I doubt that there is much 'fat' on that graphic. Anyhow, you never know before you have tried it. :-) Thanks Hartmut for the very detailed and interesting answer. Regards, Peter >> Otherwise the time consuming usage of optipng would be a complete >> waste of time. Believe it or not, but size matters :-) > > yes :-) > >> This one is for Hartmut to answer. Keep in mind that pdf does support >> pgn and jpg compression, which is not the same as 'inclusion as-is'. > > fwiw, jpg is always embedded literally (no re-compression). > >> The compresslevel concerns copyright free zip compression of streams >> (that can happen to gave image data). > > Regards, Hartmut > ___________________________________________________________________________________ > If your question is of interest to others as well, please add an entry to the > Wiki! > > maillist : [email protected] / http://www.ntg.nl/mailman/listinfo/ntg-context > webpage : http://www.pragma-ade.nl / http://tex.aanhet.net > archive : http://foundry.supelec.fr/projects/contextrev/ > wiki : http://contextgarden.net > ___________________________________________________________________________________ > ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : [email protected] / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://tex.aanhet.net archive : http://foundry.supelec.fr/projects/contextrev/ wiki : http://contextgarden.net ___________________________________________________________________________________
