On Sep 30, 2007, at 22:03, Simon Pepping wrote:
On Sat, Sep 29, 2007 at 08:59:36AM +0200, Andreas L Delmelle wrote:
Either the code in ListItemLM and others needs to be adapted to
deal with
ListElements instead of KnuthElements, or the ParagraphListElement
needs to
subclass KnuthElement instead of ListElement directly.
ParagraphListElements are not supposed be KnuthElements. The error is
genuine. After linebreaking has been applied to ParagraphListElements,
they have been replaced by KnuthBlockBoxes and similar
KnuthElements. Then the CCE will have been removed.
OK, I see. Just got to the conclusion myself that it looks quite
simple though: at some point in the process, doLineBreaking() needs
to be called to substitute the ParagraphListElements with the
corresponding list of KnuthElements. I'm just not sure where to
integrate it, yet.
One thing I was wondering about: doLineBreaking() is parameterless
for the moment. Do you see this changing in the future? i.e. If this
method can be called multiple times on the same paragraph, give it a
position to start from the second time? So something like
doLineBreaking(LayoutContext, Position)...?
If I get it correctly now, the LayoutContext is still handled through
the LineLM, while somehow I would see the LineLM as receiving the
LayoutContext only at the very latest instance. For example, the
paragraph-linefiller-width would no longer be stored in the
KnuthParagraph itself, but passed into the doLineBreaking() method.
(Long shot :S)
Concerning an earlier question/remark by Chris:
On Sep 25, 2007, at 10:19, Chris Bowditch wrote:
The page breaker can implement both the total fit strategy for a page
sequence and the best fit strategy for one page (or a range of
pages). The latter strategy allows one to have different widths for
different pages.
I am curious to know how this works. So if I want to allow changing
IPD in a page-sequence, I specify a property on the page-sequence
to indicate best-fit instead of total-fit?
I wouldn't think so. Total-fit for me precisely implies taking into
account the fact that the available IPD may alter from one page to
another. What FOP Trunk currently does in that scenario is definitely
not a total-fit, or at least, only in the case the available IPD does
not change between pages.
The key to that is the fact that FlowLM.getNextKnuthElements() gets
called only once per fo:flow, and in the base-loop passes on a
LayoutContext to its descendants with the IPD of the first page in
the page-sequence. This IPD (or a portion thereof) is ultimately used
by *all* descendant LineLayoutManagers...
Cheers
Andreas
