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Posted to fop-dev@xmlgraphics.apache.org by Glen Mazza <gr...@yahoo.com> on 2003/11/10 22:46:31 UTC

(Joerg) Re: space-before in 1.0Dev

Question, Joerg, we implement fo:block as multiple
Area.Blocks in those cases where an fo:block would
consume more than one page (or, more precisely, its
assigned region on the page).  One Area.Block for each
page the fo:block consumes.

I am assuming this is just an implementation
convenience for us--just to confirm, the spec does
allow for an fo:block to consume more than one page,
correct?  I wasn't able to find otherwise.

Glen

--- "J.Pietschmann" <j3...@yahoo.de> wrote:
> 
> First lets get it working, worry later about memory.
> The current state
> of the art is already wasting ressources.
> 

+1

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Re: (Joerg) Re: space-before in 1.0Dev

Posted by "Peter B. West" <pb...@powerup.com.au>.
As I read it, no more than normal.  If a block contains text, the 
individual glyph areas will, conceptually, be assembled into line-areas. 
  There is no FO corresponding to a line-area.  Where side-floats are 
introduced, intrusion adjustment occurs, which may affect the placement 
of text in line-areas, by affecting the appropriate intrusion-adjustment 
of the block andor line areas.  The overall IPDir geometry of the block 
area is not affected.

Peter

Jeremias Maerki wrote:
> Not that I'm a specialist in this area, but won't fo:float also cause an
> fo:block to be split into multiple areas even if the block itself
> doesn't span multiple pages?

-- 
Peter B. West <http://www.powerup.com.au/~pbwest/resume.html>


Re: (Joerg) Re: space-before in 1.0Dev

Posted by Glen Mazza <gr...@yahoo.com>.
Possibly (I haven't studied fo:float at this
time)--but we were speaking about a very specific
case, there may be many others that cause fo:blocks to
be split into multiple areas.

--- Jeremias Maerki <de...@greenmail.ch> wrote:
> Not that I'm a specialist in this area, but won't
> fo:float also cause an
> fo:block to be split into multiple areas even if the
> block itself
> doesn't span multiple pages?
> 
> On 11.11.2003 01:30:18 Peter B. West wrote:
> > I've always assumed that the one or more areas are
> a logical consequence 
> > of the fact that generating FOs may overflow a
> page.
> 
> Jeremias Maerki
> 


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Re: (Joerg) Re: space-before in 1.0Dev

Posted by Jeremias Maerki <de...@greenmail.ch>.
Not that I'm a specialist in this area, but won't fo:float also cause an
fo:block to be split into multiple areas even if the block itself
doesn't span multiple pages?

On 11.11.2003 01:30:18 Peter B. West wrote:
> I've always assumed that the one or more areas are a logical consequence 
> of the fact that generating FOs may overflow a page.

Jeremias Maerki


Re: (Joerg) Re: space-before in 1.0Dev

Posted by "J.Pietschmann" <j3...@yahoo.de>.
Peter B. West wrote:
> Recall that the contents of fo:block are defined as
> 
> (#PCDATA|%inline;|%block;)*
> 
> and that there are some interesting complications in the contents of 
> "&inline;" which, frankly, I still don't understand in spite of 
> clarifications from the editors.

One complication is whitespace because of the unfortunate mix of
block level FO and text. There's also the unpleasant problem that
  <fo:block>
     <fo:marker...
may unexpectedly trigger a fatal error because of the whitespace
before the fo:marker.
Yeah, unintended consequences of seemingly easy and straightforward
definitions. Doh.

J.Pietschmann



Re: (Joerg) Re: space-before in 1.0Dev

Posted by "Peter B. West" <pb...@powerup.com.au>.
Glen Mazza wrote:
> Thank you both for the clarifications.
> 
> --- "Peter B. West" <pb...@powerup.com.au> wrote:
> 
>> The area tree 
>>describes laid-out areas to be rendered on some
>>medium, and

as

>> every area 
>>which describes a mark on a page must have a region
>>in its ancestry, we 
>>are obliged to consider individual FOs fragmented
>>into more than one area.
>>
> 
> 
> I see...so there is a parent-child relationship
> between a region and area, meaning larger fo:blocks
> will need to be broken up into multiple areas so those
> areas can be applied to the regions on the following
> pages.  

That's it.  In general, there is an active hierarchy of FOs at any page 
break.  Recall that the contents of fo:block are defined as

(#PCDATA|%inline;|%block;)*

and that there are some interesting complications in the contents of 
"&inline;" which, frankly, I still don't understand in spite of 
clarifications from the editors.  Pages can break in the most 
unfortunate places.

Peter
-- 
Peter B. West <http://www.powerup.com.au/~pbwest/resume.html>


Re: (Joerg) Re: space-before in 1.0Dev

Posted by Glen Mazza <gr...@yahoo.com>.
Thank you both for the clarifications.

--- "Peter B. West" <pb...@powerup.com.au> wrote:
>  The area tree 
> describes laid-out areas to be rendered on some
> medium, and every area 
> which describes a mark on a page must have a region
> in its ancestry, we 
> are obliged to consider individual FOs fragmented
> into more than one area.
> 

I see...so there is a parent-child relationship
between a region and area, meaning larger fo:blocks
will need to be broken up into multiple areas so those
areas can be applied to the regions on the following
pages.  

Glen


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Re: (Joerg) Re: space-before in 1.0Dev

Posted by "Peter B. West" <pb...@powerup.com.au>.
I've always assumed that the one or more areas are a logical consequence 
of the fact that generating FOs may overflow a page.  The area tree 
describes laid-out areas to be rendered on some medium, and every area 
which describes a mark on a page must have a region in its ancestry, we 
are obliged to consider individual FOs fragmented into more than one area.

Peter

J.Pietschmann wrote:
> Glen Mazza wrote:
> 
>> I am assuming this is just an implementation
>> convenience for us--just to confirm, the spec does
>> allow for an fo:block to consume more than one page,
>> correct?  I wasn't able to find otherwise.
> 
> 
> Well, the spec always has this phrase "one or more areas".
> It doesn't really explicitely deal with how multiple areas
> come into existence and whether it is "one area per page",
> although there are the constraints on the area tree which
> indicate it has to be this way.
> 
> J.Pietschmann

-- 
Peter B. West <http://www.powerup.com.au/~pbwest/resume.html>


Re: (Joerg) Re: space-before in 1.0Dev

Posted by "J.Pietschmann" <j3...@yahoo.de>.
Glen Mazza wrote:
> I am assuming this is just an implementation
> convenience for us--just to confirm, the spec does
> allow for an fo:block to consume more than one page,
> correct?  I wasn't able to find otherwise.

Well, the spec always has this phrase "one or more areas".
It doesn't really explicitely deal with how multiple areas
come into existence and whether it is "one area per page",
although there are the constraints on the area tree which
indicate it has to be this way.

J.Pietschmann