Thanks, Rory. In hind-sight I guess my presumptions look pretty silly. The
reason I'm making mistakes like this is that I can't find any introductory
text along the lines of 'TeX for programmers'; i.e. people coming from your
typical modern imperative languages, who will (after looking at TeX
Hi again,
Another METAPOST problem. For the sake of curiosity, I've been looking at
and playing with the superellipse() function in plain METAPOST. This is all
fine and dandy until I try values of 'superness' less than 0.5, in which
case it generates shapes that are seemingly not
I should say that the vertices of the superellipse are calculated
correctly. The problem, it seems, is that for the vertices at right, top,
left, and bottom, the angles of entry and exit need to be explicitly
defined, rather than just relying on the '...' which coincidentally works
for s=0.5.
I
James's explanation appears to be right.
On p 126 of the METAFONTbook Knuth says that the superness should be
between 0.5 (when you get a diamond) and 1.0 (when you get a square).
Exercise 14.6 asks the reader to Try superellimpse with superness
values less than 0.5 or greater than 1.0; explain
I've come up with a crude function that's doing more like what I want. I
have two problems with it:
1. The most important: I need to differentiate the equations that generate a
superellipse, in order to find the tangent at the defined vertices. I have
failed to do this and so use a crude
For 2: I think Metafont makes more sense if you don't think of a macro
as a function that does some work in its own context and returns a
value, but as something that expands textually in place. So there
isn't any concept of return as there aren't separate stack frames to
return from or to.
So
