On 20.03.2007 22:54:30 Andreas L Delmelle wrote:
> On Mar 20, 2007, at 21:55, Andreas L Delmelle wrote:
>
> > On Mar 20, 2007, at 17:47, Chris Bowditch wrote:
> >
> >> <snip />
> >> Have you actually checked the code to see the difference in
> >> handling between absolute-position="absolute" and absolute-
> >> position="fixed"?
> >
> > Errm, that would be a no. I've checked: a) the Recommendation and
> > b) the resulting output.
> > I never trust code. Not someone else's, but especially not my own. ;)
>
> FWIW: re-reading the description of the value of "fixed" for absolute-
> position, I think the key difference between "absolute" and "fixed"
> can be made clearer by an example. It is a minor, yet possibly very
> important nuance.
>
> "In the case of continuous media, the area is fixed with respect to
> the viewport (and doesn't move when scrolled)."
> Suppose you are viewing the output in Adobe Reader and zoom to fit-to-
> page-width. If you scroll down, a block-container with absolute-
> position="absolute" would 'stick to' the page, while "fixed" would
> make that same block-container "absolute-positioned" relative to the
> viewport of the viewer application (until the whole page goes out of
> scope?)
Why are leaving out the paged media here? Continuous media is not really
the issue here.
> At least, that's what the example seems to want to point out, for
> AFAICT ("Authors may wish to specify 'fixed' in a media-dependent way.")
>
> OTOH, there is the following consequence
>
> >> Leaves my original question:
> >> What I'm still not sure about is: "Absolutely positioned areas are
> >> taken out of the normal flow." Does that mean that percentages on
> >> any block-container with position="absolute" should always be
> >> based on the containing page?
> >
> > I think so, but like yourself I'm not 100% certain. I think it
> > would certainly meet user expectations.
>
> The counter-intuitive answer is in the second additional restriction
> imposed by the XSL Rec.
>
> "The area generated is a descendant of the page-area where the first
> area from the object would have been placed had the object had
> absolute-position='auto' specified."
>
> This means that:
>
> <fo:block-container absolute-position="absolute" top="5mm">
> <fo:block>
> <fo:block-container absolute-position="absolute" top="5mm">
> ...
>
> is semantically equivalent to
>
> <fo:block-container absolute-position="absolute" top="5mm">
> <fo:block />
> </fo:block-container>
> <fo:block-container absolute-position="absolute" top="5mm">
> ...
I strongly disagree because the outer block-container creates a
reference area which means the second block-container would be
positioned differently in the two cases. If you talked about fixed
block-containers, then yes, the outcome would be the same, as both would
be positioned relative to the page and not the nearest ancestor
reference area.
> The offsets are, in BOTH cases relative to the containing page,
> unless absolute-position="auto".
Nonono.
> Correct?
>
>
> Cheers,
>
> Andreas
Jeremias Maerki
