'**SUMMARY**
Given a set of new corner points in clockwise order, return a shear-ed image
that transforms the image contents.  The returned image is the same
dimensions.
**PARAMETERS**
* *cornerpoints* - a 2x4 tuple of points. The order is (top_left, top_right, bottom_left, bottom_right)
**RETURNS**
A simpleCV image.
**EXAMPLE**
>>> img = Image("lenna")
>>> points = ((50,0),(img.width+50,0),(img.width,img.height),(0,img.height))
>>> img.shear(points).show()
**SEE ALSO**
:py:meth:`transformAffine`
:py:meth:`warp`
:py:meth:`rotate`
http://en.wikipedia.org/wiki/Transformation_matrix'

def shear(self, cornerpoints):

    src = ((0, 0), ((self.width - 1), 0), ((self.width - 1), (self.height - 1)))
    aWarp = cv.CreateMat(2, 3, cv.CV_32FC1)
    cv.GetAffineTransform(src, cornerpoints, aWarp)
    return self.transformAffine(aWarp)
