Adding New Shapes

ParticleScattering includes functions for drawing squircles, rounded stars, and ellipses. New shape functions can be added, provided they have the following structure:

function my_shape(args, N)
    t = Float64[π*j/N for j = 0:(2*N-1)] # or t = 0:π/N:π*(2-1/N)
    ft =  [x    y]
    dft = [dx/dt    dy/dt]
    ShapeParams(t, ft, dft)
end

Where t is the parametrization variable, ft[i,:] = [x(t[i]) y(t[i])] contains the coordinates, and dft contains the derivative of ft with respect to t. In particular, the quadrature used by ParticleScattering assumes t are equidistantly distributed in $[0, 2\pi)$, and that none of the points ft lie on the origin.