assymetry of {} @Scale

[Jeff Kingston]

Scaling to available horizontal space, which is what {} @Scale does,
happens to be well-defined in Lout because, in Lout, everything is
inside a galley and every gally has a fixed width.  Scaling to
available vertical space is rather problematic:  what if the current
page is half full and the next page is empty, do we scale to half
page size or give a page break and scale to full page size?  Anyway
Lout doesn't offer either solution; you can't do it.

If you happen to know, yourself, how much vertical space is available,
for example if you want the include to occupy a full page, then
(assuming that this space is, say, 15c) the solution is
 
   -90d @Rotate 15c @Wide {} @Scale 90d @Rotate @IncludeGraphic zog.eps
 
which artfully switches vertical to horizontal, scales to the wanted
size, and switches back again.  Stupid, but it worked for me once
long ago.  Naturally, make a definition out of this:
 
   def @HeightLimiteIncludeGraphic
      left height
      right filename
   {
      -90d @Rotate height @Wide {} @Scale 90d @Rotate @IncludeGraphic filename
   }
 
put it in your mydefs file, and use it as

   15c @HeightLimiteIncludeGraphic zog.eps

Of course, you run the risk of scaling such that the final width is too
wide for the column.  The ideal, scaling to a fixed height but less if
the result would be too wide, is not possible, I believe.

Jeff