I am trying to animate the movement of a polygon and thought a sound approach would be to in a loop where I redraw after altering the offsets value.  However I seem to not be able to scale the polygon correctly.  Here is an example of only trying to place a polygon (square) at 1,1.  You can see the translation is correct, but the scaling is wrong--the polygon is only about a pixel high & wide.

Dave

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import pylab as P
from matplotlib import collections, axes, transforms
import matplotlib.numerix as N

fig = P.figure()
a = fig.add_subplot(1,1,1)

verts = N.array([[0,0],[1,0],[1,1],[0,1]])
offsets = [[1,1]]
col = collections.PolyCollection([verts], offsets=offsets,
                                transOffset=a.transData)
a.add_collection(col)
trans = transforms.scale_transform(transforms.Value(1),transforms.Value(1))
col.set_transform(trans)
a.set_xlim([-5,5])
a.set_ylim([-5,5])
P.show()

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