On figures and clipping

[Giuseppe Bilotta <gip.bilotta@iol.it>]

Hello,

I have some problems with the way to put clipped images in ConTeXt
documents; for what I can see the correct way to do it is via
something like:

\clip
  [width=6.3cm,height=10.5cm,hoffset=0.5cm,voffset=1cm]
  {\externalfigure[ciccione_03.pdf]}

Now suppose that I wanted to put the above thing zoomed 200%;
and here I have two problems:

(a) I can't seem to find the proper number to pass on to scale= or
factor= in the \externalfigure options

(b) AFAICS I need to scale all the clipping parameters as well.

Point (b) is particularly annoying; is there a way to "pre-clip"
an image, without touching the original file? It should be
possible to specify clipping area at inclusion time (LaTeX's
graphicx package can do that ...), and therefore in a
scale-independent way (this is especially important when the scale
factor is something like "max" or "fit" or "broad").

-- 
Giuseppe "Oblomov" Bilotta