page-viewport-area content-rectangle

Resending due to mail problems.  My apologies for any multiple occurrences.

-------- Original Message --------
Subject: page-viewport-area content-rectangle
Date: Thu, 19 Feb 2004 10:31:14 +1000
From: Peter B. West <[email protected]>
To: xsl-editors <[email protected]>
CC: fop-dev <[email protected]>

The editors,

The nub of my question is, "Why do the page margins establish a distance
between the content rectangle of the page-viewport-area and the
page-reference-area, when for other viewport/reference pairs, they
establish a distance between both the viewport and reference content
rectangle and some enclosing reference area, at least for some dimension?"

For example, in "6.4.12 fo:simple-page-master", "Constraints applicable
to regions", it is stated that "If the flow assigned to the
corresponding region is an fo:flow formatting object, then
     *
       If the value of the media-usage trait is paginate, or the value
of the overflow trait is visible, hidden, or error-if-overflow, then the
block-progression-dimension of the region-reference-area is constrained
to be no greater than the block-progression-dimension of the
region-viewport-area."

An number of conditions concerning media-usage and the block-progression
dimension of the region-reference-area are stated, but, it seems to me,
the margins which were specified on the region-master play no part in
the development of that dimension, apart from providing a common
starting point for both the region-viewport-area and the
region-reference-area.  This is seen in the definitions for region-body,
where the margins (defined on the region-master for the region-body,
with respect to the content-rectangle of the page-reference-area) are to
accommodate the four boundary regions.
http://www.w3.org/TR/xsl/slice6.html#fo_simple-page-master
Region-viewport-areas diagram, and in the 'Margins of a page'
(MediaReferenceArea.html) and 'Two page model examples'
(PageAndRegion-bodyWithOrientationOnPage.html) diagrams, and in
http://www.w3.org/TR/xsl/slice6.html#fo_region-body in the diagram 'A
close-up of the first case in the previous figure'
(PageAndRegion-bodyMargins.html).

Is there an inconsistency between the page-level viewport/reference pair
ans other viewport/reference pairs, notably the region-body pair?  If
so, is it intentional?  To what purpose?

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