Some writing-mode questions

[kl...@club-internet.fr]

Dear editors,

I've got a couple of issues regarding writing-mode where I'd like to
make sure I'm interpreting the spec as you intended.
-------------------------------------------
Issue 1: whose writing-mode determines the value of corresponding
absolute properties.

Section 4.2.3 states:
"For purposes of this definition, the content-rectangle of an area uses
the inline-progression-direction and block-progression-direction of that
area; but the border-rectangle, padding-rectangle, and
allocation-rectangle use the directions of its parent area."

I assume this implies that when calculating the corresponding absolute
properties for properties such as padding-start, border-start-*,
space-*, start-indent as described in Chapter 5.3 one uses the
writing-mode of the nearest ancestor reference area-creating FO rather
than the FO's own writing-mode (assuming the current FO also creates
reference areas).

Referring to the figure in section 4.2.3, where a "tb-rl" area is nested
in a "lr-tb" one, start-indent for the inner area would thus be measured
from the left side of the outer content rectangle to the left side of
the inner content rectangle. Padding-start and border-start-width for
the inner area area would be equivalent to padding-left and
border-left-width and not padding-top and border-top-width.

On the other hand, if inline-progression-dimension or
block-progression-dimension are specified on an FO which establishes a
reference area and specifies a writing-mode, these are calculated in
that writing-mode. (Section 5.3.3 uses the phrase "the writing-mode in
effect for the formatting object".) In the figure described above,
inline-progression-dimension for the inner rectangle would thus be the
vertical dimension.

Is that the correct reading?
-------------------------------------------
Issue 2. Writing-mode on region-master vs. writing-mode on flow and its
descendants.

In 7.27.7 the recommendation states: 'The "writing-mode" property
applies only to formatting objects that set up a reference-area (for XSL
these are: fo:simple-page-master, fo:region-*, fo:table,
fo:block-container, and fo:inline-container. '

Since the writing-mode property isn't listed as applying to flow or
static-content objects, this would seem to imply that text in a flow
(outside of a table, block-container or inline-container which can
specify its own writing-mode) is supposed to get its writing mode from
the fo:region-* into which it is laid out!

This doesn't seem reasonable since the writing-mode should be determined
by the content of the flow and not the page-masters into which one flows
it. If that were the case, there would be no way to calculate
corresponding absolute property values until an area were placed on a
page. As an implementator, this gives me nightmares.

I would prefer to think of writing-mode as applying to the flow, which
is indirectly generating reference areas in the region-body. It would
still be possible to have a pathological situation where the flow
writing-mode was different from the region-body writing mode. This could
produce strange layout effects, but it wouldn't influence the property
value calculations.

What was the intention?
-------------------------------------------
Thanks in advance for clarifying these points,


Karen Lease
FOP'er
Senior Software Developer/Consultant
SPX Valley Forge

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