Re: Percentages in CommonAbsolutePosition?

[Vincent Hennebert <vi...@anyware-tech.com>]

Hi,

Manuel Mall a écrit :
> On Tuesday 20 March 2007 04:10, Andreas L Delmelle wrote:
<snip/>
>> A fix for the left-percentage is setting the PercentBase on the
>> PropertyMaker for "left" to LengthBase.CONTAINING_BLOCK_WIDTH in
>> FOPropertyMapping.createAbsolutePositionProperties().
>> Although I'm not sure whether that is completely correct. Should the
>> 16% be relative to the outer block-container, or to the page (since
>> the inner block-containers' positions are also absolute)?

To the outer block-container, which generates a ref-area. That would be
relative to the page if the value of "absolute-position" were "fixed".
If I'm correct...

However, the following statement in §7.6.5 of the XSL-FO rec is a bit
unclear:
"The left, right, top, and bottom are interpreted in the prevailing
coordinate system (established by the nearest ancestor reference area)
and not relative to the "containing block" as in CSS."
Does that apply only to the edge from which the block should be shifted,
or also to the length?
It seems you chose the nearest ref-area in your patch, but I can't have
a definite opinion towards one or the other possibility.


>> Anyway, for the top-percentage, setting the percent-base still
>> doesn't seem to be enough, although it fixes the issue described
>> above. The parsed property is no longer a FixedLength.
>>
>> I'll see if I can track that last one down as well.
>>
> 
> My understanding of the spec is that for "top" and "bottom" percentages 
> only make sense if the containing block has a fixed height. If the 
> containing block has a variable height percentages are suppose to be 
> ignored and the property value assumed to be "auto".

I second that, see the CSS2 spec [1]: "For 'top' and 'bottom', if the
height of the containing block is not specified explicitly (i.e., it
depends on content height), the percentage value is interpreted like
'auto'."

[1] http://www.w3.org/TR/1998/REC-CSS2-19980512/visuren.html#position-props


Vincent

Re: Percentages in CommonAbsolutePosition?

[Jeremias Maerki <de...@jeremias-maerki.ch>]

On 20.03.2007 11:56:10 a_l.delmelle wrote:
> >----- Oorspronkelijk bericht -----
> >Van: Vincent Hennebert [mailto:vincent.hennebert@anyware-tech.com]
> 
> >Manuel Mall a écrit :
> >> 
> >> My understanding of the spec is that for "top" and "bottom" percentages 
> >> only make sense if the containing block has a fixed height. If the 
> >> containing block has a variable height percentages are suppose to be 
> >> ignored and the property value assumed to be "auto".
> >
> >I second that, see the CSS2 spec [1]: "For 'top' and 'bottom', if the
> >height of the containing block is not specified explicitly (i.e., it
> >depends on content height), the percentage value is interpreted like
> >'auto'."
> >
> >[1] http://www.w3.org/TR/1998/REC-CSS2-19980512/visuren.html#position-props
> 
> CSS doesn't have the last word here. See the definition for the 'left'
> property (XSL-FO 1.1 - §7.6.5) all the way at the bottom. In XSL, these
> are interpreted relative to the prevailing coördinate system. Not to
> the containing block as in CSS, but to the nearest ancestor reference area.
> 
> I'd think a similar substitution holds for the definition of a
> <percentage> value a bit higher up, so that "the offset is a percentage
> of the /nearest ancestor reference area/'s width"
> 
> Agreed?

Yes. This part about the "prevailing coordinate system" is an addition
of XSL 1.1. The WG tried to make this clearer. See:
http://www.w3.org/TR/xsl11/#change10

Jeremias Maerki