XKCD-style graphs in matplotlib

xkcd.py

import numpy as np
from matplotlib import rcParams
rcParams['text.usetex'] = False
from matplotlib.backends.backend_agg import FigureCanvasAgg as fc
from matplotlib.figure import Figure
import matplotlib.font_manager as fm

# Function to draw a random function. Yo dawg...
def rand_func():
    # Some random Fourier coefficients
    coeffs = 0.0 + 1j * np.random.random(129)

    for i in range(len(coeffs)):
        if i == 0:
            coeffs[i] = 0.0
        elif i == (len(coeffs) / 2) + 1:
            coeffs[i] = 0.0
        else:
            # Make those bad boys decay. Fo' regularity, yo.
            coeffs[i] /= float(i) ** 1

    f = np.fft.irfft(coeffs, 256)
    return np.append(f, f[0])

# Make some data
x = np.linspace(1.0, 9.0, num=257, endpoint=True)
y1 = 1.5 + 10.0 * (np.sin(x) * np.sin(x) / np.sqrt(x)) * np.exp(-0.5 * (x - 5.0) * (x - 5.0))
y2 = 3.0 + 10.0 * (np.sin(x) * np.sin(x) / np.sqrt(x)) * np.exp(-0.5 * (x - 7.0) * (x - 7.0))

# Add the jiggles
scale = 25.0
y1 += rand_func() * scale
y2 += rand_func() * scale

# Set up a figure
fig = Figure()
canvas = fc(fig)

# Plot the data
ax = fig.add_subplot(1, 1, 1)
ax.plot(x[5:-5], y1[5:-5], 'c', lw=2)
ax.plot(x[5:-5], y2[5:-5], 'white', lw=7)
ax.plot(x[5:-5], y2[5:-5], 'r', lw=2)
ax.set_ylim(0, 10)

# Poor man's x-axis. There's probably a better way of doing this.
xaxis = [0.0] * 257
xaxis += rand_func() * 10.0
ax.plot(x[3:-3], xaxis[3:-3], 'k', lw=2)
ax.arrow(8.75, xaxis[-3], 0.1, 0, fc='k', head_width=0.2, head_length=0.15)

# Poor man's x-tick
x = [4.75, 4.75]
yaxis = [-0.1, 0.1]
ax.plot(x, yaxis, 'k', lw=1.5)

# XKCD font. This won't work on your machine. Install the font
# and change the path to the place where you installed it.
prop = fm.FontProperties(fname='/Users/damon/Library/Fonts/Humor-Sans.ttf')
ax.text(4.5, -0.5, 'PEAK', fontproperties=prop, size=11)

# Turn off decoration
ax.set_xticks([])
ax.set_yticks([])
ax.set_xticklabels([])
ax.set_yticklabels([])
ax.set_frame_on(False)

# Turn off all clipping
def noclip(ax): 
     "Turn off all clipping in axes ax; call immediately before drawing" 
     ax.set_clip_on(False) 
     artists = [] 
     artists.extend(ax.collections) 
     artists.extend(ax.patches) 
     artists.extend(ax.lines) 
     artists.extend(ax.texts) 
     artists.extend(ax.artists) 
     for a in artists: 
         a.set_clip_on(False) 
noclip(ax)

# Save
fig.savefig('xkcd.png')