xkcd-ify a plot

xkcd-style.py

from pylab import *
import scipy.signal as signal
from scipy.stats import norm
import matplotlib.font_manager as fm

def rand_func(data):
    """ multiply data by low-pas filtered random values 
        data - input data array
    """
    length=size(data)
    coeffs = norm.rvs(loc = 0, scale = 1e-2, size = length) # random values
    b = signal.firwin(80, min(1,30./length))
    response = signal.lfilter(b,1,coeffs)+1 # use low pass filter to smooth variations
    return data*response

def make_xkcd(ax,x_label='',y_label=''):
    """ make an xkcd style plot
        ax - axis element
        x_label, y_label - optional text for x and y axis
    """

    # add randomness to x and y of plotted lines
    pltlist=ax.get_lines()
    for p in pltlist:
        x = p.get_xdata()
        y = p.get_ydata()
        x = rand_func(x)
        y = rand_func(y)
        p.set_xdata(x)
        p.set_ydata(y)

    ax.axison = False
    # get boundaries for x and y axis
    xmin, xmax = ax.get_xlim()
    ymin, ymax = ax.get_ylim()
    xsize=xmax-xmin
    ysize=ymax-ymin
    # Increase figure size to fit new custom axes
    BORDER=10. # border size
    xmin -=xsize/BORDER
    xmax +=xsize/BORDER
    ymin -=ysize/BORDER
    ymax +=ysize/BORDER
    ax.set_xlim(xmin, xmax)
    ax.set_ylim(ymin, ymax)
    
    # Poor man's x-axis
    xlen=size(x)
    xaxis = linspace(xmin,xmax-xsize/BORDER,xlen)
    yaxis = rand_func([ysize] * xlen)-ysize+ymin+ysize/BORDER
    ax.plot(xaxis, yaxis, 'k', lw=2)
    ax.arrow(xaxis[-1], yaxis[-1], 1e-6, 0, fc='k', lw=2, head_width=ysize/30, head_length=xsize/BORDER)

    # Poor man's y-axis
    xaxis = rand_func([xsize] * xlen)-xsize+xmin+xsize/BORDER
    yaxis = linspace(ymin,ymax-ysize/BORDER,xlen) 
    ax.plot(xaxis, yaxis, 'k', lw=2)
    ax.arrow(xaxis[-1], yaxis[-1],0, 1e-6, fc='k', lw=2, head_width=xsize/40, head_length=ysize/BORDER);
    
    # Add axis description text
    # The font is available here: http://antiyawn.com/uploads/Humor-Sans.ttf
    prop = fm.FontProperties(fname='c://windows/fonts/Humor-Sans.ttf')
    a=ax.text(xmax, ymin, x_label, fontproperties=prop, size=14,rotation=2,horizontalalignment='right')
    ax.text(xmin, ymax, y_label, fontproperties=prop, size=14, rotation=88,verticalalignment='top');