Compute bounding box for an ellipse.

ellipse_bounding_box.ipynb

This can return min values that are greater than their corresponding max values, e.g. when a negative angle is supplied. Recommend you wrap these lines in sorted(), e.g.

    [max_x, min_x] = sorted([x + major / 2 * np.cos(t) * np.cos(np.radians(angle_deg)) -
                      minor / 2 * np.sin(t) * np.sin(np.radians(angle_deg)) for t in (t, t + np.pi)],reverse=True)
    t = np.arctan(minor / 2 * 1. / np.tan(np.radians(angle_deg)) / (major / 2))
    [max_y, min_y] = sorted([y + minor / 2 * np.sin(t) * np.cos(np.radians(angle_deg)) +
                      major / 2 * np.cos(t) * np.sin(np.radians(angle_deg)) for t in (t, t + np.pi)],reverse=True)

Thanks @drscotthawley! I fixed the notebook with slightly modified code.

@smidm what happens if angle_dim==0? I get NaNs with a warning:

RuntimeWarning: invalid value encountered in double_scalars
  t = np.arctan(-minor / 2 * np.tan(np.radians(angle_deg)) / (major / 2))

To avoid this, I just added a little fudge factor above that line:

    if 0==angle_deg: angle_deg = 1e-8      # slight fudge to avoid division by zero