From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.comp.tex.context/46897 Path: news.gmane.org!not-for-mail From: Arthur Reutenauer Newsgroups: gmane.comp.tex.context Subject: Re: PDF Meta Tags Date: Tue, 20 Jan 2009 16:19:04 +0100 Message-ID: <20090120151904.GO22175@phare.normalesup.org> References: <200901192206.37977.bntgcontext@wiseguysweb.com> <20090120111008.GL22175@phare.normalesup.org> <200901200651.36129.bntgcontext@wiseguysweb.com> Reply-To: Mailing list for ConTeXt users NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1232464839 15401 80.91.229.12 (20 Jan 2009 15:20:39 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 20 Jan 2009 15:20:39 +0000 (UTC) To: Mailing list for ConTeXt users Original-X-From: ntg-context-bounces@ntg.nl Tue Jan 20 16:21:51 2009 Return-path: Envelope-to: gctc-ntg-context-518@m.gmane.org Original-Received: from ronja.vet.uu.nl ([131.211.172.88] helo=ronja.ntg.nl) by lo.gmane.org with esmtp (Exim 4.50) id 1LPIQ7-0007H7-JY for gctc-ntg-context-518@m.gmane.org; Tue, 20 Jan 2009 16:21:39 +0100 Original-Received: from localhost (localhost [127.0.0.1]) by ronja.ntg.nl (Postfix) with ESMTP id E22471FDEB; Tue, 20 Jan 2009 16:20:19 +0100 (CET) Original-Received: from ronja.ntg.nl ([127.0.0.1]) by localhost (smtp.ntg.nl [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 16886-01-4; Tue, 20 Jan 2009 16:19:49 +0100 (CET) Original-Received: from ronja.vet.uu.nl (localhost [127.0.0.1]) by ronja.ntg.nl (Postfix) with ESMTP id 9B3771FDE0; Tue, 20 Jan 2009 16:19:49 +0100 (CET) Original-Received: from localhost (localhost [127.0.0.1]) by ronja.ntg.nl (Postfix) with ESMTP id 048271FDE0 for ; Tue, 20 Jan 2009 16:19:47 +0100 (CET) Original-Received: from ronja.ntg.nl ([127.0.0.1]) by localhost (smtp.ntg.nl [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 14305-02-2 for ; Tue, 20 Jan 2009 16:19:18 +0100 (CET) Original-Received: from filter1-til.mf.surf.net (filter1-til.mf.surf.net [194.171.167.217]) by ronja.ntg.nl (Postfix) with ESMTP id 4C6751FD83 for ; Tue, 20 Jan 2009 16:19:18 +0100 (CET) Original-Received: from nef2.ens.fr (nef2.ens.fr [129.199.96.40]) by filter1-til.mf.surf.net (8.13.8/8.13.8/Debian-3) with ESMTP id n0KFJ6l6002387 for ; Tue, 20 Jan 2009 16:19:10 +0100 Original-Received: from phare.normalesup.org (phare.normalesup.org [129.199.129.80]) by nef2.ens.fr (8.13.6/1.01.28121999) with ESMTP id n0KFJ4lx019357 for ; Tue, 20 Jan 2009 16:19:05 +0100 (CET) X-Envelope-To: Original-Received: by phare.normalesup.org (Postfix, from userid 1008) id D7604BC0AD; Tue, 20 Jan 2009 16:19:04 +0100 (CET) Content-Disposition: inline In-Reply-To: <200901200651.36129.bntgcontext@wiseguysweb.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.1.4 (nef2.ens.fr [129.199.96.32]); Tue, 20 Jan 2009 16:19:05 +0100 (CET) X-Bayes-Prob: 0.0001 (Score 0, tokens from: @@RPTN) X-CanIt-Geo: ip=129.199.96.40; country=FR; region=A8; city=Paris; latitude=48.8667; longitude=2.3333; http://maps.google.com/maps?q=48.8667,2.3333&z=6 X-CanItPRO-Stream: uu:ntg-context@ntg.nl (inherits from uu:default, base:default) X-Canit-Stats-ID: 168098972 - 8fa1f74c53a3 X-Scanned-By: CanIt (www . roaringpenguin . com) on 194.171.167.217 X-Virus-Scanned: amavisd-new at ntg.nl X-BeenThere: ntg-context@ntg.nl X-Mailman-Version: 2.1.11 Precedence: list List-Id: mailing list for ConTeXt users List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: ntg-context-bounces@ntg.nl Errors-To: ntg-context-bounces@ntg.nl X-Virus-Scanned: amavisd-new at ntg.nl Xref: news.gmane.org gmane.comp.tex.context:46897 Archived-At: > But he did say that his > printing shop wants the ability to download just the header information from a > pdf rather than the whole pdf file which may be up to 80 mbytes. OK. That's not Tagged PDF. Tagged PDF's main features focus on accessibility, adding information for the visually impaired (you can, for example, tag some text as part of the page header, by contrast to the page body: an application that reads the document out loud would know not to read that part). It also allows better archiving (the PDF/A standard). All concerns very distinct from the needs of publishers. I'm just learning about XMP (Extensible Metadata Platform) which Luigi mentioned, but it doesn't really look like it contains the information you mention (although you can apparently add all sort of metadata, including images). Actually, the kind of information the printing shop asks for is available in any PDF file in a straightforward way: the very format has been designed so that all the PDF objects can be accessed directly with extreme efficience (there is a cross-reference table with the byte offsets to every object inside the file). Individual pages are objects in a PDF file; they contain references to the resources needed to render them (fonts, images, etc.), so the basic functionality to render each page individually is already present in the format. And it's been there from day one -- which is, by the way, the reason why the insides of a PDF file look so undecipherable to the human eye: it's designed to be efficient to process automatically, not to be read by a programmer. By contrast, an XML-based format would be (somewhat) more human-friendly, but much slower to parse. There's a variation on this basic feature: if you look at a PDF file over the Internet, the cross-reference table isn't conveniently located because it is at the very end of the file; so you need to download the entire file before your PDF viewer can start displaying it (I think the argument behind that design decision was that a PDF-producing application only knows the entire list of objects at the end of the first pass, and can thus output the whole file sequentially in a single pass. Of course that clashes directly with the needs of PDF-consuming applications). To circumvent this, Adobe devised a special type of object that contains the same information as the cross-reference table, which you can put at the very beginning of the file, together with the material needed to render the first pages. This is Linearized PDF (sometimes, confusingly enough, called "optimized" PDF). It's rather unlikely that it'd be what your printer wants (I suppose the file is already available on disk somewhere), but in any case, Ghostscript can produce it with the utility pdfopt. ConTeXt isn't able to produce it; it has been ruled that it was beyond the scope of pdfTeX and luaTeX. > When I get specific information from the printing shop, I'll pass it along. I'm interested, too. > But needless to say, I'm very concerned. If tagged pdf support is not > available in ConTeXt/LuaTeX, I feel that difficulties are either here now, or at > best, looming on the horizon. Why? There's progress made every day. Tagged PDF is indeed a problem for the moment, but it's clearly not the feature your printer asks for, and as a rule, you can be sure that if some functionality is essential to publishers, it will be added quickly to ConTeXt :-) Arthur ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://tex.aanhet.net archive : https://foundry.supelec.fr/projects/contextrev/ wiki : http://contextgarden.net ___________________________________________________________________________________