# ------------------------------------------------------------------------------
# Rotate all markers in the active path tracer marker set.
#
def rotate_markers(xform):

    from VolumePath import volume_path_dialog
    d = volume_path_dialog()
    if d == None:
        return          # No marker sets exist.

    ms = d.active_marker_set
    if ms == None:
        return          # No marker set chosen in dialog.

    from chimera import Point
    for m in ms.markers():
        xyz = m.xyz()   # Python tuple
        txyz = xform.apply(Point(*xyz)).data()
        m.set_xyz(txyz)

# ------------------------------------------------------------------------------
# Convert Euler angles to an equivalent Chimera transformation matrix.
#
# Angles must be in degrees, not radians.
#
# Uses the most common Euler angle convention (the chi-convention) described at
#
#   http://mathworld.wolfram.com/EulerAngles.html
#
def euler_transform(phi, theta, psi):

    from chimera import Xform, Vector
    xf1 = Xform.rotation(Vector(0,0,1), phi)    # Rotate about z-axis
    xp = xf1.apply(Vector(1,0,0))               # New x-axis
    xf2 = Xform.rotation(xp, theta)             # Rotate about new x-axis
    zp = xf2.apply(Vector(0,0,1))               # New z-axis
    xf3 = Xform.rotation(zp, psi)               # Rotate about new z-axis

    xf = Xform()
    xf.premultiply(xf1)
    xf.premultiply(xf2)
    xf.premultiply(xf3)

    return xf

# ------------------------------------------------------------------------------
#
xf = euler_transform(30, 60, 45)
rotate_markers(xf)