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From Luca Furini <lfur...@cs.unibo.it>
Subject Re: Necessary conditions to defer footnotes
Date Wed, 12 Jul 2006 15:47:57 GMT
Vincent Hennebert wrote:

> there is something I don't get with the handling of footnotes. When
> there is not enough room on the current page to place all the footnotes,
> the algorithm tries to find a place where to split them. But there is a
> condition: it must be possible to defer old footnotes
> (PageBreakingAlgorithm, l.332). And this is possible only if there is no
> legal breakpoint between the previous active node and the currently
> considered breakpoint (checkCanDeferOldFootnotes method). I don't
> understand this latter condition?

This is to avoid keeping deferring part of the old footnotes when there is 
no real need to do it.

Let me explain with an example: let's pretend we have a long footnote, 
which cannot be wholly placed on the same page where its citation is; so, 
when we start building the following page we should try to place all the 
remaining "old" footnote lines, if this is possible.

However, it can happen that the breaking algorithm, without this check, 
prefers filling the page with "normal" lines, such placing just a single 
footnote line and deferring the others to the next pages.

For example, the footnote has 10 lines, and 3 are placed on the first page 
while the others are deferred one first time as there is not enough space 
for them; without this condition, it could happen that if there are no new 
footnotes (which would force a "flush" of the old one) the algorithm 
places just a single footnote line in the following seven pages, filling 
the remaining space with normal lines, while we want the footnote to be 
deferred again only if there is no way to place lines 4 to 10 together.

> And, reading the code, I don't understand if this method's purpose is to
> determine if it is /allowable/ to defer footnotes (am I authorized to
> defer footnotes if any), or if it is /possible/ (are there footnotes to
> defer). Ok, this is a bit subtile, but understanding that would help me
> get the intent of the algorithm.

The former one, the method purpose is to determine if the algorithm is 
allowed to break the foonote once again, which can happen only if we have 
added only the slightest bit of normal lines () and the remaining space is 
not enough.

If there are no old footnotes the method return false (which is maybe not 
very clear), but has no effect.

HTH

     Luca

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