AW: AW: Embedding XMP in FO
Hi Jeremias, > We're hoping for any help we can get to bring the > redesign effort to a point where we can release again. I'm pretty > certain now, that will happen sometime next year, but not before summer. I will see what I can do... thanks for the info anyway. > Hm My guess is that you didn't take the right approach. See > below for an example of an external FOP extension. It could be, however, > that the old code (and maybe even the new) doesn't handle namespace > prefixes in attributes well. It works now... well it would have worked before: For testing I fancy-dumped the XMP stream in a separate file. Fancy dump but incomplete dump :-)... Stupid mistake. Bye, Victor
AW: Embedding XMP in FO
Hi,
> 3) Leaf text nodes are not submitted to
> FObj.addCharacters(...).
hupps, that's not exactly true :-). addCharaters(...) *is* called and the
text node is appended to the appropriate element, but when dumping the
complete DOM this text node is missing.
Here is the XMP:
http://www.w3.org/1999/02/22-rdf-syntax-ns#";>
http://ns.adobe.com/xap/1.0/";>
Vendor Application XYZ
Here is the code:
~
protected void addCharacters ( char data[], int start, int length ) //
overrides ExtensionObj.addCharaters(...)
{
String str = new String( data, start, length );
Text text = this.document.createTextNode( str );
this.element.appendChild(text); // this works for all elements but for
xap:CreatorTool
}
After dumping the DOM:
~~
http://www.w3.org/1999/02/22-rdf-syntax-ns#";>
http://www.w3.org/1999/02/22-rdf-syntax-ns#";>
http://ns.adobe.com/xap/1.0/"/>
Any ideas?
Thanks,
Victor
Re: AW: Embedding XMP in FO
On 09.12.2004 08:27:18 Victor Röder wrote: > Hi Jeremias, > > > you haven't told us what branch you are on. Are you on the maintenance > > branch or on FOP HEAD? > > I suppose I'm working with the 0.20.5 code base... > > > 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. > > I didn't had the chance to look at the HEAD branch yet. Is it in an > stable/usable state? Usable? Depends. :-) Stable? No. It's where we concentrate all our efforts because the old maintenance branch is a dead end. The design of the layout engine doesn't allow any further progress towards full specification compliance. That's why we decided to freeze the maintenance branch. We're hoping for any help we can get to bring the redesign effort to a point where we can release again. I'm pretty certain now, that will happen sometime next year, but not before summer. > > 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. > > I tried to build up a separated DOM with the XMP data in it (similarly to > the SVG stuff). But I think there are several restrictions so that I doubt > that this could be done with the 0.20.5 sources. > Examples: 1) There is no way to define an own PropertyHandler. There are two > for FO and SVG, but they are in the fop.jar as class files. 2) The SAX > parser does not submit the prefix bindings for namespaces (e.g. > xmlns:xap="http://ns.adobe.com...";) as attributes. They are missing in the > PropertyList. 3) Leaf text nodes are not submitted to > FObj.addCharacters(...). Hm My guess is that you didn't take the right approach. See below for an example of an external FOP extension. It could be, however, that the old code (and maybe even the new) doesn't handle namespace prefixes in attributes well. > > 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. > > Yes, you're right. Attaching it to the 'root' and to a 'block' or > 'foreign-instream-object' is sounder. > > > 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. > > Thanks, it helped me out. But I don't think that the 0.20.5 sources will get > me any further... Btw: Did you notice that it does not compile if you remove > the fop.jar with compiled sources from the classpath? There seem to be > inconsistent packages between the fop.jar and the actual source directory > tree. Not sure, but could it be that you're forgetting that during the build process code gets generated using XSLT in the build/codegen directory? At least, I don't see any problems with the maintenance branch build. > > I hope this helps nonetheless. We're looking forward to your patches for > > FOP HEAD. ;) > > Well, we'll see :-). One request: Please do not see SVG as the *only* > foreign XML vocabulary that one could embed in FO :-). We don't. For example, I'm the author of Barcode4J which has a FOP extension that enables you to use a special namespace to specify a barcode in an fo:instream-foreign-object. It didn't even have to modify the source code to implement this. See: http://barcode4j.krysalis.org/fop-ext.html Maybe the source code of that FOP extension might help you because they do pretty much what you're trying to do: building a DOM from the elements in the extension namespace. http://cvs.sourceforge.net/viewcvs.py/barcode4j/barcode4j/src/fop-0.20.5/java/org/krysalis/barcode4j/fop0205/ I'm sorry that I don't have more time right now to dive in further but maybe this helps. Jeremias Maerki
AW: Embedding XMP in FO
Hi Jeremias, > you haven't told us what branch you are on. Are you on the maintenance > branch or on FOP HEAD? I suppose I'm working with the 0.20.5 code base... > 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. I didn't had the chance to look at the HEAD branch yet. Is it in an stable/usable state? > 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. I tried to build up a separated DOM with the XMP data in it (similarly to the SVG stuff). But I think there are several restrictions so that I doubt that this could be done with the 0.20.5 sources. Examples: 1) There is no way to define an own PropertyHandler. There are two for FO and SVG, but they are in the fop.jar as class files. 2) The SAX parser does not submit the prefix bindings for namespaces (e.g. xmlns:xap="http://ns.adobe.com...";) as attributes. They are missing in the PropertyList. 3) Leaf text nodes are not submitted to FObj.addCharacters(...). > 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. Yes, you're right. Attaching it to the 'root' and to a 'block' or 'foreign-instream-object' is sounder. > 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. Thanks, it helped me out. But I don't think that the 0.20.5 sources will get me any further... Btw: Did you notice that it does not compile if you remove the fop.jar with compiled sources from the classpath? There seem to be inconsistent packages between the fop.jar and the actual source directory tree. > I hope this helps nonetheless. We're looking forward to your patches for > FOP HEAD. ;) Well, we'll see :-). One request: Please do not see SVG as the *only* foreign XML vocabulary that one could embed in FO :-). Thank you, Victor
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
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
