On 04 May 2011, at 22:57, Giuseppe Briotti wrote: Hi Guiseppe
Apologies for the delayed response. > Hi all, I'm really interested on merge-pages-across-index-key-references / > merge-sequential-page-numbers / merge-ranges-across-index-key-references. You are addressing a feature that would greatly improve usability and basic compliance. It has been requested a couple of times now, but not enough to lead to action, unfortunately... > > As per http://wiki.apache.org/xmlgraphics-fop/FormattingObjectsForIndexing it > seems that they are: I had started to compile some basic ideas on that page, in an attempt to separate out the core functionality, i.e. the components that *definitely* need to be added to make even the smallest possible example work. > 1) "Rather straightforward properties to implement on the FO tree side > (simple enums)." > 2) "Of lesser importance for the base implementation." > 3) "If FOP can get to the point where it correctly outputs a sequence of > page-numbers for a given index-key, these will be relatively easy features to > add. " > > The point (1) suggests that this is not so complicated. Well, it is ultimately still a challenge, as it is so comprehensive (= changes will affect multiple packages, requiring an understanding of different areas of the code and how they work together). > The point (2) suggests that this feature is not so close to complete. Apart from having added the symbolic literals in org.apache.fop.fo.Constants --for the new properties, property enum values and FOs-- nothing is in place yet. Some properties can be quite straightforwardly implemented, if they are simple enum values. (see also: http://wiki.apache.org/xmlgraphics-fop/PropertyHandling) However, the "merge-*" properties by themselves are useless. On the other hand, "(ref-)index-key" both are *required* for a minimal implementation. > The point (3) suggests that there is some kind of problem to correctly > outputs a sequence of page numbers. Not really a problem. As pointed out above, it requires understanding the FO tree part /and/ the layout engine. In that respect, the reference to the (ref-)id property-pair is, IMHO, rather crucial. Make sure to study closer how these are processed/passed, and you will get a lot closer to an implementation for (ref-)index-key. Once a base implementation is in place to be able to produce a separated list of all page-numbers, the remaining non-essential stuff --whether to merge sequential page-numbers-- would be trivial to add. As for new FO objects, I think the first pair is all we need to get a proof-of-concept for such a base implementation working. The second pair, related to index-ranges, only becomes relevant in the context of merge-*, so is considered non-essential. The TBDs are really only cosmetics, although we might want to take care to make the separator replaceable (i.e. not a hard-coded comma or semi-colon or some such...) > I know that I can use a "double-pass" approach and act on Intermediate > Format. I can figure out if it possible to obtain the same result by a new > extension or implementing such feature in the FOP code. > > I would like to try :-) > > Any suggestion? If a standard feature covers your requirements, but is not implemented, then obviously from our perspective, you are very much encouraged to try and add this. :-) If some the above does not immediately make sense or raises further questions, just chime back in here. Thanks! Regards, Andreas
