Chemical Engineering package

[Federico Zenith <zenith chemeng ntnu no>]

Hi all,
I developed a collection of Dia shapes useful in drawing
chemical-engineering process-flow diagrams. Here they are:
http://www.nt.ntnu.no/~zenith/dia/dia.html

I already used the package for some real work, i. e. a few redrawings of
process flow diagrams for my academic tutor's second edition of his book
prosessteknikk (in Norwegian), and in minor extent to draw a detailed
scheme of a sieve-tray distillation column for a student lab I'll be an
assistant for.

I developed the package either at home or overtime at work, so any IP
claims from the university are not feasible. Anyway this place is the
last in the world where they would make such claims, so no problem.

Some comments about my experience:

The .shape export is a bit strange. All elements tend to get a
style="fill: none; stroke-width: 0.1; stroke: #000000": I had to change
them all manually to "fill: default", which would allow the user to
change the figure's colour. While having more than one colour definable
in a single picture would be nice, I understand that it implies much
more work.
Anyway, what about dispensing with that 0.1-stroke stuff? The
modification would be much simpler and that would make production of new
figures easier for beginners.

I noticed that when I tell the program to draw a figure with 0 line
thickness, it draws it with 0.01. I must admit I do not know whether the
issue has been debated before, so don't flame me please...:-) But
figures with no borders are indeed useful and I used them plenty of
times in .shape files (where I had to insert style="fill:default;
stroke:none").

About dotted/dashed lines et similia: what about implementing the
possibility of a dotting/dashing pattern related to the actual size of
the object, to improve scalability? A 1 meter long line with 1 mm dashes
is one thing, but when it scales down to 1 cm the visual effect is
definitely different. Maybe it should be possible for the user to choose
either "x mm" (or inches, feet, middle fingers or whatever insane unit
the Americans use :-), or a given fraction of the line length, say x/100
line length for instance.

Cheers everybody!
-Federico