Hi,
I'll answer to my own contribution! After isolating the cause of the
problem (making a line coexist with an insert), we can see that the
solution does not completely solve the problem, since we can see in the
PDF output of the MWE that there is something wrong with the transition
between page 1 and page 2.
After applying the macro that measures the height of the
|\placesidebyside| material and places the marginal with
|voffset=-\ht<box>|, most of the original problem is solved: the
marginal is correctly aligned with the side-by-side block and no longer
drifts to the bottom of the page. However, there is still a residual
issue at a page boundary. In the PDF output, one can observe that at the
transition from page 1 to page 2, the side-by-side material (the
orange/black rules) is placed at the bottom of page 1, while the
marginal (|MARG|) is deferred and appears at the top of page 2. This
happens only at the page break and breaks the visual association once.
This behavior is still consistent with ConTeXt’s page-builder logic. In
the current macro, the order is essentially:
1.
register the marginal as an insert,
2.
then add the measured box to the vertical list.
In my opinion if the page is nearly full at that point and the box does
not fit, the page builder decides to break /before/ the box. The box is
moved to the next page, but the insert has already been registered for
the current page and is therefore separated.
In other words: measuring the box is not sufficient if the insert is
emitted before the page decision is final.
I may be mistaken here, but after looking at the remaining page-break
behavior, it seems that the core issue might not be the measurement
itself, but /when/ the marginal is emitted with respect to the
page-builder’s decision. My current hypothesis is that, as long as the
marginal is registered as an insert *before* the page break is
finalized, it can still be separated from the following material — even
if its vertical position is computed correctly. This would explain why
the alignment works in most cases, yet still fails exactly at a page
boundary. If that reading is correct, then the only way to guarantee
that the marginal and the side-by-side material are never separated
would be to make them belong to the same placement unit from the page
builder’s point of view.
One possible approach would be to construct a single |\vbox| that
already contains both the marginal and the |\placesidebyside| material,
and then let ConTeXt place that box as a whole. For example:
|\def\SideBySideWithInnerMarg#1#2#3{%\begingroup\setbox0\vbox{%\ininner{#1}%\placesidebyside{#2}{#3}%}%\box0
\endgroup} |
In this setup (assuming my understanding is correct):
*
the marginal is emitted /inside/ the box,
*
the page builder no longer has the option to place the insert and
the block independently,
*
either the whole unit fits on the current page, or it is moved
entirely to the next page.
Regarding positioning and alignment, once the marginal is inside the
|\vbox|, it seems that manual |voffset| on the insert itself should no
longer be the right tool. Instead, alignment would need to be handled by:
*
adjusting the internal layout of the box (e.g. struts or vertical
spacing),
*
or, if necessary, by measuring and shifting the /box as a whole/.
If this reasoning holds, the important point is that any recalculation
now applies to the |\vbox|, not to an insert whose page placement has
already been decided. I would be very interested to know whether this
matches how others understand the page-builder behavior, or if I am
missing something obvious here.
Best//JP
Le 18/02/2026 à 21:45, Jean-Pierre Delange via ntg-context a écrit :
Hraban,
From what I understand, the marginal is an insert attached to a line,
and |\placesidebyside| is a vertical block; without a reliable line
anchor, ConTeXt pushes it away. A solution? Either force a line anchor
(|\dontleavehmode ... \par|), or (better) encapsulate
|\placesidebyside| in a box and apply a |voffset| calculated on |\ht|
of the box (so the marginal follows the block, even if it jumps from
page to page). I don't know if the following MWE is the most elegant
or effective (or robust) approach, but it seems to work (at least for
me, the test is functional, even though I haven't tested it beyond two
pages). I don't know if that's really the goal you're looking for
either...You'll tell me !
Best//JP
\starttext
\def\SideBySideWithInnerMarg#1#2#3{%
\begingroup
\setbox0\vbox{%
\placesidebyside{#2}{#3}%
}%
% On place le marginal "après", mais on le remonte d'une hauteur de box
\ininner[voffset=-\ht0]{#1}%
\box0
\endgroup
}
\input{ward}
\dorecurse{7}{%
\SideBySideWithInnerMarg
{MARG}
{\blackrule[width=3cm,height=3cm,color=orange]}
{\blackrule[width=3cm,height=2cm]}
\par
\input{ward}\par
}
\stoptext
Le 18/02/2026 à 18:33, Henning Hraban Ramm a écrit :
Hi,
if I call a marginal before a \placesidebyside (don’t know how to
call that more generally), it gets placed only at the bottom, and
sometimes on the next page (couldn’t reproduce that in the MWE).
If I use the voffset option, I can move it up, but only manually,
since I don’t know the height of the following construct – in my
book, that’s a code example beside the result. And voffset doesn’t
help if the marginal moved to the next page.
Do you have a solution?
"""
\starttext
\ininner{MARG}
\input{ward}
\dorecurse{7}{
%\ininner[voffset=-3cm]{MARG}
\ininner{MARG}
\placesidebyside
{\blackrule[width=3cm,height=3cm,color=orange]}
{\blackrule[width=3cm,height=2cm]}
\input{ward}\par
}
\stoptext
"""
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If your question is of interest to others as well, please add an entry to the
Wiki!
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