Peter B. West wrote: > It occurs to me that some of the implications of the FAD > approach have not been successfully communicated. Part of > this may well be because of my own inadequate understanding > of the FOP process. Before I continuing with this > discussion, I had better ensure that my understanding of one > important point is correct. Why does FOP process in minimum > units of a page-sequence?
1. To process in units smaller than a page-sequence presents layout dependency problems. An item on the last page of a page-sequence can theoretically change the layout of something on the first page. 2. To process in units larger than page-sequence presents memory-usage problems. Except for things like unresolved page numbers in other page-sequences (deemed to have an acceptable workaround), you can layout a page-sequence in isolation from the other page-sequences. BTW, although the main purpose of the FO Tree event-firing mechanism (recently removed from HEAD) was to allow different layout engines to react to page-sequence objects in different ways, one of the IMO advantageous side-effects was that other high-level events could be fired as well, allowing a layout engine to use something other than page-sequence as a trigger. I thought at the time that this might be helpful to those wanting a more "eager" layout strategy. Victor Mote