change orientation of contour clabel text objects
<p>I'm using Python Matplotlib to plot contours. Here's some code I have below as a basis. If you run this, you'll see that the labels are almost at vertical. I'd like to get the labels orientated horizontal, but I have no idea how can achieve this. I've tried with <code>ClabelText</code>, which the documentation suggests, but don't understand how this is supposed to work. I'd appreciate if someone could suggest a way to orientate the labels, either with or without ClabelText.</p>

<pre><code>import itertools as it
import numpy as np
from matplotlib.ticker import FuncFormatter
from matplotlib.contour import ClabelText
import matplotlib.pyplot as plt
from math import pi, log 

def getTime(data):
    M = data['weight']
    Tei  = data['temp']
    Twasser = 99.8
    Teikl = 86.0  ## max allowed temp
    k = 0.262 ## estimate was 0.3 W/(m.K),
    Crho = 3.18 # (KJ/kgC)
    const = pow(Crho, 1.0/3) / (pi*pi*k*pow(4*pi/3,2.0/3))
    Tval = const*pow(M,2.0/3)*log(0.76*(Tei-Twasser)/(Teikl-Twasser))
    return Tval # coo time in minutes

def contourFmt(val, posn):
    mins = int(val // 1)
    secs = int(val % 1 *60)
    return '{0:d}mm{1:d}ss'.format(mins, secs)

def labeler(val): #is this any use??
    print(val)
    return

#weights = np.array(range(40, 80, 5))*1.0
#temps = np.array(range(0, 30, 5))*1.0
weights = np.arange(40.0, 80.0, 5.0)
temps = np.arange(0.0, 25.01, 5.0)

X = temps
Y = weights
Z = np.zeros((len(X), len(Y))) 
xx = [{'temp':i} for i in X]
yy = [{'weight':i} for i in Y]
plt.figure()

##zz = it.product(xx,yy)

for i, xdicts in enumerate(xx):
    for j, ydicts in enumerate(yy):
        zd = {}
        zd.update(xdicts)
        zd.update(ydicts)
        zval = getTime(zd)
        Z[i,j] = zval

times = np.arange(4.00, 6.50, 0.25)
CS = plt.contour(Y, X, Z, levels=times, colors='b')

lbl = ClabelText(labeler)
lbl.set_rotation('horizontal')
formatter = FuncFormatter(contourFmt)  
#plt.clabel(CS, inline=True, fmt=formatter, fontsize=12)
plt.clabel(CS, inline=True, use_clabeltext=True, fmt=formatter, fontsize=12)

plt.grid(True)
plt.clabel(CS, inline=1, fontsize=12)
plt.show()
</code></pre>