On Wed, 19 Oct 2005 05:44 am, Jeremias Maerki wrote:
> I've started to comment on the individual issues you listed and only
> when I got to the examples I realized there must be something wrong.
> You place the white-space-treatment after the white-space-collapse
> but I think it is clear that the latter comes last ("during area tree
> construction" =after line breaking vs. "during line-building and
> inline-building" =before line-breaking). That's why you run into
> problems explaining why there is no line generated by the white space
> between the two starting block elements. Maybe clearing this up might
> clear up some of the other issues.
>
Jeremias,yes I agree that this is a critical interpretation issue and I expected that part of the algorithm to be controversial. The problem is that in the description of value "true" for the white-space-collapse property it clearly refers to the fo tree and fo:character siblings in the tree. That was further clarified by an e-mail on the xsl editor list http://lists.w3.org/Archives/Public/xsl-editors/2002OctDec/0004. Once we have done line-building the fo tree (at fo:character level) is largely gone, we have now glyph areas which could have been merged, ligatures combined, etc.. That means referring at this stage back to fo:character siblings in the fo tree seems lets say unusual. The fact that we are dealing with glyph areas and not fo:character elements in line-building / area tree construction is further emphasised by the description of the handling for the white-space-treatment property. It is all defined in terms of glyph areas not fo:characters. Further to this it doesn't make sense to me to collapse white space after line breaking as is implied by your interpretation because the amount of white space does contribute to the line breaking decisions. If we remove white space after line breaking we would IMO get sub optimal line breaks. In summary I think white space must be collapsed before or at least during line breaking but not after. Another related issue is the description of collapsing white space around a linefeed in the spec under white-space-collapse. The spec is very specific and refers to U+000A (linefeed) fo:character siblings in the fo tree. This is obviously very different to removing white space around a line break generated during line building. Also in the default case by the time we get to white-space-collapse handling all linefeeds would have been replaced by spaces during refinement. Which leads to the question do they really mean that in the spec or do they really meant to remove white space around a line break? But then again that is really dealt with by the white-space-treatment property in much more detail. But why then do we need the duplication of white-space-collapse removing white space around a linefeed character and white-space-treatment removing white space (not quite actually - it removes characters with the suppress-at-line-break property being true) around line breaks? <snip/> >> Manuel > > Jeremias Maerki Manuel
