Offset and slip ALL OF EM KEYFRAMES on nodes

slip.py

import nuke, re

def start_anim_at(node, frame):
    """
    Will move all the animations of the passed node so that they start at the passed frame instead of the
    current ont
    """
    slip_by = frame - first_keyframe_location(node)
    slip_animations_of_node(node, slip_by)
    
def first_keyframe_location(node):
    """
    Returns the first frame which contains an animated keyframe for the selected node
    """
    first_frames = []
    # Walk all the knobs of the object and check if they are animated.
    for knob_name in node.knobs():
        k = node[knob_name]
        if k.isAnimated():
            for curve in k.animations():
                first_frames.append(curve.keys()[0].x)
    return min(first_frames)
    
def slip_animations_of_node(node, by_offset):
    """
    This function will slip all the animations of the passed node by a passed
    offset in frames
    """
    # Offsets the frames in the passed curve TCL script
    def offset_frames_in_curve(curve_str, offset):
        def offset_replace(m):
            if "." in m.group(1):
                return "x%0.3f" % (float(m.group(1)) + offset)
            else:
                return "x%d" % (int(m.group(1)) + offset)
        return re.sub(r"x([-+]?\d*\.\d+|\d+)", offset_replace, curve_str)
    
    # Walk all the knobs of the object and check if they are animated.
    for knob_name in node.knobs():
        k = node[knob_name]
        if k.isAnimated():
            k.fromScript(offset_frames_in_curve(k.toScript(), int(by_offset)))


def align_camera_to_read():
    """
    Will detect the first Camera node in selection and align it's keyframes to start
    at the first frame of the first selected Read node. Useful if you got a camera track
    starting at 1 and a Read node starting at an arbitrary frame
    """
    read, cam = None, None
    for node in nuke.selectedNodes():
        if "camera" in re.node.Class().lowercase():
            cam = node
        if node.Class() == "Read":
            read = node

    if cam and read:
        # Get the start frame of the Read
        start = int(read["frame"].getValue())
        # And BAM - let the camera start there
        start_anim_at(cam, start)