# Builds a polar graph in a square Canvas.

from ROOT import TGraphPolar, TCanvas, TMath
from array import array

c = TCanvas("myCanvas","myCanvas",600,600)
rmin = 0.
rmax = TMath.Pi()*6.
npoints = 300
r = array('d',[0]*npoints)
theta  = array('d',[0]*npoints)
for ipt in xrange(0,npoints):
    r[ipt] = ipt*(rmax-rmin)/npoints+rmin
    theta[ipt] = TMath.Sin(r[ipt])

grP1 = TGraphPolar(npoints,r,theta)
grP1.SetTitle("A Fan")
grP1.SetLineWidth(3)
grP1.SetLineColor(2)
grP1.DrawClone("L")
raw_input("Press enter to exit.")