Re: Plotting TODO

[Nils Barth <nbarth@fas.harvard.edu>]

Thus spake Aaron Lehmann:
> I looked at this dir, some plots look pretty hard. However, if you can
> compute vector fields, I can draw them into a drawing area fairly easily
> :).

hehe -- well, you wanted a challenge, eh?
re: vector fields.
computing them is trivial:
given two functions (the x-component and the y-component):
(f(x,y),g(x,y)), just evaluate f and g at a bunch of points.
For example, if f(x,y)=sin(x), g(x,y)=cos(x*y), to plot the vector
field, just choose a bunch of points
(say, (0,0), (1,0), (2,0), ... (5,0), (0,1), ... (5,1), ... (0,2)
.. (5,2), ... (5,5))
and then at the point (x,y), put the vector (f(x,y),g(x,y))

Is this what you're looking for w/r/t `computing vector fields'?

The other concerns with plotting vector fields are the assorted
scaling options (this is easy to add in later -- for instance, you
might ask to scale all vectors by a factor of 1/2 so they don't crash
into each other or something), and rotated arrowheads (which is a bit
harder, but should be easy with any library that offers affine
transforms -- what's the GNOME replacement for Imlib?)

-- 
  -nils