On Mar 26, 2007, at 11:47, [EMAIL PROTECTED] wrote:
If I understand you correctly, what you're saying is that if the
fixed
positioned block's nearest ref-area is not initially visible, then
the
top/left/etc. properties should be taken WRT the region-viewport-
area?
Almost... What I'm saying is that if the fixed-positioned block's
nearest ancestor reference area is not visible, then the viewport-
area will also not be visible. I've been searching around, but
could not immediately find an example of a situation where a
reference-area is established without an accompanying viewport-
area. Regular fo:blocks generate normal block areas, which are not
reference-areas...
Diving into the viewport/reference-area relation some more, I think
what I could as well have said from the beginning was:
If the nearest ancestor reference area is the region-reference-area,
then the position of a fixed-positioned area in the viewport is
initially identical to that of an absolute-positioned area.
By means of an example, if you have:
<fo:block>
<fo:block-container absolute-position="absolute" top="5%" left="5%">
...</fo:block-container>
<fo:block-container absolute-position="fixed" top="5%" left="15%">
...</fo:block-container>
Rest of block
</fo:block>
Then the areas corresponding to the block-containers will be
positioned at the resolved coördinates in the nearest ancestor
reference area, whatever that is. In this case, the same top,
slightly different left.
My point: Even if the rest of the block's content gets clipped or
even if the content gets clipped somewhere way above the block, both
block-containers should still be rendered at the specified
coördinates in the reference-area and so, initially also in the
viewport-area.
Those coördinates specify an absolute position in the reference-area
for absolute-position="absolute" and a fixed position in the
accompanying viewport-area for absolute-position="fixed".
See the light? I don't think it overcomplicates the situation, quite
on the contrary. To the renderers, maybe, since many of them need to
process that "relative-absolute" position into one that maps to
absolute positions on the page...
Cheers,
Andreas
