On Thu, 31 Mar 2016 21:49:56 -0400 (EDT)
Aditya Mahajan <adityam@umich.edu> wrote:

On Thu, 31 Mar 2016, Alan BRASLAU wrote:

On Thu, 31 Mar 2016 17:51:07 -0400
Aditya Mahajan <adityam@umich.edu> wrote:

@Hans: Does it make sense to disable \incrementcounter if
\trialtypesetting is active?

I was going to suggest such things...

My motivation is different. If you have any macro in a table (or anything
that requires multiple runs to get the size right) that uses a counter
(e.g., enumeration), then the numbers will be off. That would not happen
if a counter is frozen when trialtypesetting is on.

P.S. Would not the use of \startcombination\stopcombination be an
alternative to the placefigures within a table?

And \startcombination\stopcombination fails when you use \placefigure instead of \externalfigure because you want the captions to be numbered and included in the list of figures. You get an error like this one 

      > tex error on line 7 in file virtual: . . .  ! You can't use `\prevdepth' in restricted horizontal mode

Using \startfloatcombinations\stopfloatcombination (which appears to be undocumented) avoids this error.



combinations only give regular grid. Sometimes you want an irregular grid.
For example, the OP wanted

+-------+------+
|          |         |
|          | Fig2 |
| Fig1 +-------+
|          | Fig3 |
|          |         |
+------+-------+

Such layouts are not possible using combinations.

I thought that nesting combinations might enable this type of combination but it didn’t work. see
https://mailman.ntg.nl/pipermail/ntg-context/2016/084926.html

Using tables is a better solution because it has the syntax to handle figures that span rows or columns


Aditya

Lots of things seem to work well with external figures but as soon as you embed them in a \placefigure, which makes them a float, you make things more complex and run into the possibility of triggering the restricted horizontal mode  error.

It seems to me that once you place an object that is normally a float inside another float you want the inner one to lose it floating characteristics. Is there a way do this explicitly i.e. instead of creating an inner float with

\placefigure[force][ref1]{this is the caption }{\externalfigure[cow][width=3in,height=1in]}

could we create a non-floating version with something explicit like

\externalfigure[cow][width=3in,height=1in]
\addcaption[figure][ref1]{this is the caption }

Aidan