def get_rotation_and_scale(header, skew_threshold=0.001):
    ((xrot, yrot),
     (cdelt1, cdelt2)) = get_xy_rotation_and_scale(header)

    if math.fabs(xrot - yrot) > skew_threshold:
        raise ValueError("Skew detected: xrot=%.4f yrot=%.4f" % (
            xrot, yrot))
    rot = yrot

    lonpole = float(header.get('LONPOLE', 180.0))
    if lonpole != 180.0:
        rot += 180.0 - lonpole

    return (rot, cdelt1, cdelt2)
Test if VTK object changes when trait is changed.
dataset/ETHPy150Open ejeschke/ginga/ginga/util/wcs.py/get_rotation_and_scale--crossover with--dataset/ETHPy150Open enthought/mayavi/tvtk/tests/test_tvtk.py/TestTVTK.test_do_change