# coding: utf-8
#!/usr/bin/env python
from __future__ import division
import matplotlib.pyplot as plt
from matplotlib.pyplot import annotate
from matplotlib.colors import rgb_to_hsv, hsv_to_rgb, ColorConverter, rgb2hex
from numpy import array, sin, cos, pi

def pie_colors(n, base_color='#1241dd'):
    """ Generate suitable colors, adapted from:
    http://stackoverflow.com/a/5651670/878419 """

    cc = ColorConverter()
    r, g, b = cc.to_rgb(base_color)
    color = array([[r, g, b]])
    hue = rgb_to_hsv(color)[0, 0, 0]
    colors = []
    step = 1 / n
    for i in range(n):
        next_color = rgb_to_hsv(color)
        next_color[0, 0, 0] = (hue + step*i) % 1.0
        rgb_color = hsv_to_rgb(next_color)
        r = rgb_color[0, 0, 0]
        g = rgb_color[0, 0, 1]
        b = rgb_color[0, 0, 2]
        colors.append(rgb2hex((r, g, b)))
    return colors

fig = plt.figure(figsize=(7, 4))
ax = fig.add_subplot(111)

# Data
fracs = [45, 34, 10, 8, 1, 1, 1]
labels = ("USA", "Deutschland", "Taiwan", "Norwegen", "Japan", "Spanien",
          u"Großbritannien")
pieColors = pie_colors(len(fracs))

ax.set_position([0.2, 0.0, 0.4, 0.75])
p = plt.pie(fracs, startangle=90, colors=pieColors)
plt.axis("equal")

# Annotations
y1s = []
for p1, l1, f1 in zip(p[0], labels, fracs):
    r = p1.r
    dr = r*0.1
    t1, t2 = p1.theta1, p1.theta2
    theta = (t1+t2)/2.

    xc, yc = r/2.*cos(theta/180.*pi), r/2.*sin(theta/180.*pi)
    x1, y1 = (r+dr)*cos(theta/180.*pi), (r+dr)*sin(theta/180.*pi)
    if x1 > 0 :
        x1 = r+2*dr
        ha, va = "left", "center"
        tt = -180
        cstyle = "angle,angleA=0,angleB=%f" % (theta,)
    else:
        x1 = -(r+2*dr)
        ha, va = "right", "center"
        tt = 0
        cstyle = "angle,angleA=0,angleB=%f" % (theta,)

    # Prevent overlapping text
    y1 = round(y1*10)/10
    if any([(abs(y1 - y) < 0.15) for y in y1s]):
        y1 = max(y1s) + 0.15

    l1 = l1 + '; ' + str(f1) + '%'
    annotate(l1, (xc, yc), xycoords="data", xytext=(x1, y1), textcoords="data",
             ha=ha, va=va, arrowprops=dict(arrowstyle="-",
             connectionstyle=cstyle, patchB=p1))

    y1s.append(y1)

plt.title(u"Länderaufteilung 2010", y = 1.2)
plt.savefig("pv-global-2010.svg", transparent=True, bbox_inches='tight')