Info on Avalon Framework
Gang, you may have heard about what happened in Avalon-land. Looks like the project has failed from a community POV. So, just for those who don't know already, Avalon Framework which we use in FOP has been transferred over to the Avalon Excalibur project (http://excalibur.apache.org/). The source code is here: https://svn.apache.org/repos/asf/excalibur/trunk/framework/ The announcement: http://www.mail-archive.com/users@avalon.apache.org/msg05033.html My impression is that the package will remain active and maintained this way, so actually this doesn't change anything for us. Jeremias Maerki
Re: Good news: Jeremias has been elected as an ASF member!
Bertrand Delacretaz wrote: I have the great pleasure to announce that Jeremias Maerki has been elected as an ASF member at the last member's meeting during ApacheCon. Congratulations! J.Pietschmann
Re: Embedding XMP in FO
Hi Victor, you haven't told us what branch you are on. Are you on the maintenance branch or on FOP HEAD? These hints are targeted at FOP HEAD code but some can be applied to the maintenance branch, too, although the whole mechanism is quite different there. One thing you will have to do is creating an ElementMapping class (plus node subclasses, or you extend the existing ExtensionElementMapping) so the FOTreeBuilder can create nodes for each XML element of the various namespaces in the metadata part. A good example in your case is the bookmarks support code you can find in the org.apache.fop.fo.extensions package. There you have an example of an ElementMapping class (ExtensionElementMapping) and node classes (Bookmarks/Outline). That's the first step. The other issue is getting the metadata through to the PDFRenderer. Since this is not an InstreamForeignObject or an ExternalGraphic, you cannot use that infrastructure. But since the Bookmarks support is quite similar to what you want to do, just follow these classes through the code. I'm not sure if attaching the metadata to a page-sequence is the right approach. The page-sequence itself isn't represented in the resulting PDF. You might also have multiple page-sequences in a document. So you should probably attach it to fo:root where it applies to the whole document. Attaching metadata to individual pages or objects is probably trickier. So for the fo:root attachment it is probably best to enhance the Root class to catch the XMP data, just as it was done for Bookmarks. The FO tree is one thing, you will also have to enhance the ...area.AreaTreeHandler for the metadata. There's a class ...area.BookmarksData you might want to look at. PDFRenderer.processOffDocumentItem() is finally responsible to generate the outlines in the PDF. This can probably be used for the metadata, too. This should give you a few pointers into the code. I'm not sure if I got everything right, because I'm not so familiar with this part, yet. Hopefully, my colleagues will correct me if I wrote anything wrong. I hope this helps nonetheless. We're looking forward to your patches for FOP HEAD. ;) On 02.12.2004 09:43:44 Victor Röder wrote: > Hi Fop developers, > > I'm using FOP to produce PDFs and I'm trying to embed XMP (a set of XML > metadata-describing vocabularies "from" Adobe) in FO. These XMP packets > should be serialized (nearly) one-to-one in a PDF tag for metadata. > Here is an simple example: > > > > http://www.w3.org/1999/02/22-rdf-syntax-ns";> > xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/";> > uuid:foo:id-0815 > > > > > > [...] > > > > This XMP metadata says that the generated PDF "page sequence" is made of the > sample.tiff. > > Serialized to PDF it should look something like: > (the best would be only for the first page of the TIFF page sequence) > > 7 0 obj > << /Type /Metadata /Subtype /XML /Length 541 >>stream > xmlns:x="adobe:ns:meta/" x:xmptk="XMP toolkit 2.9-9, framework 1.6"> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns";> rdf:about="autodoc:tiff:c:/sample_path/sample.tiff" > xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/";>uuid:foo:id- > 0815 end="w"?> > endstream > endobj > > Now my challenge: How can I do this as simple as possible. I tried to extend > the FOP sources but permanently get lost, while searching how the FObjs of > the FOTree get ready for the List of PDF objects to be rendered. > > The problem is not the knowledge about XSL-FO nor PDF. I just don't have a > view through the FOP sources. With which things do I have to start to embed > the so-called foreign XML? I tried XMLObj but only got an "[ERROR] null". > > Thanks in advance for your responce! > > Bye, > Victor Jeremias Maerki
Re: Knuth linebreaking questions
On Thu, Dec 02, 2004 at 12:16:55PM +0100, Finn Bock wrote: > >and point #4 uses the user-definable threshold; where should this constant > >be stored? Inside the code of LineLM or in a configuration file? > > An extension attribute? > > ... > > I suspect that the other knuth parameters should be specified the same > way. But it is not a high priority IMO. It is not a layout specification in the fo file, it is a fine-tuning of the algorithm applied by a particular FO Processor. It should be in the user configuration. It may be specified in the configuration file, or it may be specified by the calling application in the configuration object FOUserAgent.userConfig. In the configuration file it should be something like: 5 other parameters FOUserAgent should get appropriate methods to extract the layout part of the configuration and pass it on to a client class, e.g. LineLM. Cf. FOUserAgent.getUserRendererConfig(). TeX's terms are pretolerance and tolerance for the two values of maxAdjustment. Regards, Simon -- Simon Pepping home page: http://www.leverkruid.nl
More questions on line breaking.
Hi Some more questions. 1) What is inactiveList doing. Nodes are added but never used. 2) If there is no shrink in a line (the case in START alignment) then nodes are never removed from activeList until a forced break element is found. Is that really the intention of the algorithm? It seems suspect that a ration of INFINITE_RATIO is also created when the break is too wide to fit within a node. regards, finn
Re: Knuth linebreaking questions
And why not adjust the spacing within the user specified min/max for START and END alignment? [Luca] Should the user desire adjusted spaces, wouldn't it be better for him to specify justified alignment? :-) Seriously, the recommendation (at 7.16.2 "letter-spacing" and 7.16.8 "word-spacing") states that these spaces "may also be influenced by justification", but says nothing about start and end alignments. I tend to read that to mean that word spacing may be pushed beyond the specified range by justification. And I would think that unjustified alignment still has the option of using the word-spacing range but ofcourse has to stay within the range. I'm still not sure why it would be ok to ignore any user specified min and max values of 'word-spacing' during START and END alignment. If a user specifies a length range, what would the reason be for not using it? Perhaps with additional DEFAULT_SPACE_WIDTH. When alignment is start or end, each space has always its .optimum width, so there is no need to look at the .minimum and .maximum: the user most preferred value is already used. Is there anything that prevents using a non .optimum value within the range if the result is judged to be better (with a lower demerit). Ok, performance is indeed a fine reason, but IMHO such quality vs. speed tradeoffs should eventually be made by the user rather than us. Simon told the same: # Note that in TeX such thresholds are user-adjustable parameters. I # think they should eventually be so in FOP too, for those of us who # have the most exquisite taste of line layout. and I think it's a good idea; the algorithm should: 1 find breaking points without hyphenation 2 hyphenate 3 find breaking points with hyphenation 4 decide which ones are "better" and point #4 uses the user-definable threshold; where should this constant be stored? Inside the code of LineLM or in a configuration file? An extension attribute? ... I suspect that the other knuth parameters should be specified the same way. But it is not a high priority IMO. regards, finn
Re: Good news: Jeremias has been elected as an ASF member!
Bertrand Delacretaz wrote: I have the great pleasure to announce that Jeremias Maerki has been elected as an ASF member at the last member's meeting during ApacheCon. Hey, that's good news. Congrats to Jeremias! Keep up your great work. -- Oleg Tkachenko http://blog.tkachenko.com Multiconn Technologies, Israel
Re: Knuth linebreaking questions
Finn Bock wrote: (starting from the second question) > And why not adjust the spacing within the user specified min/max for > START and END alignment? Should the user desire adjusted spaces, wouldn't it be better for him to specify justified alignment? :-) Seriously, the recommendation (at 7.16.2 "letter-spacing" and 7.16.8 "word-spacing") states that these spaces "may also be influenced by justification", but says nothing about start and end alignments. > I'm still not sure why it would be ok to ignore any user specified > min and max values of 'word-spacing' during START and END alignment. > If a user specifies a length range, what would the reason be for not > using it? Perhaps with additional DEFAULT_SPACE_WIDTH. When alignment is start or end, each space has always its .optimum width, so there is no need to look at the .minimum and .maximum: the user most preferred value is already used. But the knuth algorithm would not work if there were no elements with adjustable width (glue with stretchability and/or shrinkability); the actual value used is not very relevant, because the computed adjustment ratio will not be applied. > Ok, performance is indeed a fine reason, but IMHO such quality vs. > speed tradeoffs should eventually be made by the user rather than us. Simon told the same: # Note that in TeX such thresholds are user-adjustable parameters. I # think they should eventually be so in FOP too, for those of us who # have the most exquisite taste of line layout. and I think it's a good idea; the algorithm should: 1 find breaking points without hyphenation 2 hyphenate 3 find breaking points with hyphenation 4 decide which ones are "better" and point #4 uses the user-definable threshold; where should this constant be stored? Inside the code of LineLM or in a configuration file? Regards Luca
Re: Good news: Jeremias has been elected as an ASF member!
> I have the great pleasure to announce that Jeremias Maerki has > been elected as an ASF member at the last member's meeting > during ApacheCon. Congratulations! Luca
Embedding XMP in FO
Hi Fop developers, I'm using FOP to produce PDFs and I'm trying to embed XMP (a set of XML metadata-describing vocabularies "from" Adobe) in FO. These XMP packets should be serialized (nearly) one-to-one in a PDF tag for metadata. Here is an simple example: http://www.w3.org/1999/02/22-rdf-syntax-ns";> http://ns.adobe.com/xap/1.0/mm/";> uuid:foo:id-0815 [...] This XMP metadata says that the generated PDF "page sequence" is made of the sample.tiff. Serialized to PDF it should look something like: (the best would be only for the first page of the TIFF page sequence) 7 0 obj << /Type /Metadata /Subtype /XML /Length 541 >>stream http://www.w3.org/1999/02/22-rdf-syntax-ns";>http://ns.adobe.com/xap/1.0/mm/";>uuid:foo:id- 0815 endstream endobj Now my challenge: How can I do this as simple as possible. I tried to extend the FOP sources but permanently get lost, while searching how the FObjs of the FOTree get ready for the List of PDF objects to be rendered. The problem is not the knowledge about XSL-FO nor PDF. I just don't have a view through the FOP sources. With which things do I have to start to embed the so-called foreign XML? I tried XMLObj but only got an "[ERROR] null". Thanks in advance for your responce! Bye, Victor
