Andreas,

Thanks for the prompt help.  It's pretty close to what I need.

For those not interested in the arcane details of what I'm trying to do
with these forms, skip the rest of this message.

What I've done is written a simple "tool" in Squeak that allows someone
to select  a folder full of full-sized digital images and generate
a set of web pages for viewing those images.  These web pages have 
simple
navigation tools and thumbnails for each digital image, allowing simple 
selection for viewing.

It's not a new concept.  I just prefer to do this sort of thing with
Squeak.  And I get to learn a little bit more about Form and BitBlt.

Here's an example of the application of my first pass at this tool:
http://w3.one.net/~swessels/pages/steve/family-vac-2002/index.html

To make that work I used a pixel copy technique.  It's pretty slow.  
Hence the request
for help.

Here (http://w3.one.net/~swessels/images/other/example.jpg) is a screen 
capture of
trying to use BitBlt without doing pixel copies.  Using Andreas' 
suggestion,
you can see the bottom of the workspace and the displayed results.

The original digital photograph is a large JPEG image.  The first form,
"scaledForm", is the original photograph drawn in the proper smaller
size for my intended thumbnail.

"newForm" is showing several steps combined.  It is a white form of the
final size for the thumbnail.  "scaledForm" was drawn onto "newForm", 
then
using round mask forms I white-out the four corners to make them round.
The CornerRounder morph is not used for several reasons.  Although I 
could
probably extend that morph's utility methods to operate on Forms now.  
That's
another discussion.

The "shadowForm" is a composite drawn from several smaller Forms.  I 
did not
adopt the shadow methods from Morphs.  I wanted a subtle but different 
look.

"maskForm" is like "newForm" except the drawing pixels are all black.  
It is
a 1-bit deep form.

"tempForm" is the result of applying Form erase with BitBlt, using the
"scaledForm" and "maskForm".

"destForm" is the result of applying "tempForm" with the Form paint 
rule.
Note from the workspace code shown that "shadowForm" had been drawn 
there
first.  It's very close to what I want.  However, the lower right corner
of the drawing shows bleed-through of the original "shadowForm" because
"scaledForm" has black pixels in that corner.  When I make these 
thumbnails
larger it's very obvious.

The "pixelCopied" drawing is what I want (and am currently using).  
It's the
goal-image and is drawn in the slower manner.  I walk through the 
"scaledForm"
pixel-by-pixel, check if the "maskForm" is black for that same pixel, 
and then copy it
to the final form.  This keeps the corner shadow images intact since 
they
are masked out and it rounds off the corners using the mask itself as
a guide.

So, not quite there yet.

  - Steve