Matplotlib: Rotating a figure (patch) and applying

I want to apply different transformations to a patch, including rotating and changing the fill color. Hier is the piece of code already inspired by Matplotlib: rotating a patch

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import matplotlib as mpl
from matplotlib.collections import PatchCollection

fig = plt.figure()
ax = fig.add_subplot(111)

myAngles=[0, -45, -90]
myColors=[30, 40, 50]
myPatches=[]

for color, angle in zip (myColors,myAngles):
    #r2 = patches.Rectangle((0,0), 20, 40, color=color,  alpha=0.50)
    r2 = patches.Rectangle((0,0), 20, 40)
    t2 = mpl.transforms.Affine2D().rotate_deg(angle) + ax.transData
    r2.set_transform(t2)
    #ax.add_patch(r2)
    myPatches.append(r2)

    plt.xlim(-20, 60)
    plt.ylim(-20, 60)

    plt.grid(True)


collection = PatchCollection(myPatches, cmap=mpl.cm.jet, alpha=0.5)
collection.set_array(np.array(myColors))
ax.add_collection(collection)

plt.show()

Unfortunatly, the transformation is lost when I get out of the for loop. If I add the patch to the ax inside the loop, then everything is fine. But I have to do it at the end, because the colors are collected in the loop and should be applied later on.

Advices of any kind are highly appreciated

Cheers

Armel

I get this figure:

when I comment out the +ax.transData from the transform definition:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import matplotlib as mpl
from matplotlib.collections import PatchCollection

fig = plt.figure()
ax = fig.add_subplot(111)

myAngles=[0, -45, -90]
myColors=[30, 40, 50]
myPatches=[]

for color, angle in zip (myColors,myAngles):
    #r2 = patches.Rectangle((0,0), 20, 40, color=color,  alpha=0.50)
    r2 = patches.Rectangle((0,0), 20, 40)
    t2 = mpl.transforms.Affine2D().rotate_deg(angle) #+ ax.transData
    r2.set_transform(t2)
    #ax.add_patch(r2)
    myPatches.append(r2)

    plt.xlim(-20, 60)
    plt.ylim(-20, 60)

    plt.grid(True)


collection = PatchCollection(myPatches, cmap=mpl.cm.jet, alpha=0.5)
collection.set_array(np.array(myColors))
ax.add_collection(collection)

fig.savefig('withoutTransData.png')
plt.show()