animation_motion_trail.py

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#
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bl_info = {
    "name": "Motion Trail",
    "author": "Bart Crouch",
    "version": (3, 1, 3),
    "blender": (2, 80, 0),
    "location": "View3D > Toolbar > Motion Trail tab",
    "warning": "Needs bgl draw update",
    "description": "Display and edit motion trails in the 3D View",
    "doc_url": "https://wiki.blender.org/index.php/Extensions:2.6/Py/"
               "Scripts/Animation/Motion_Trail",
    "tracker_url": "https://developer.blender.org/maniphest/task/edit/form/2/",
    "category": "Animation",
}


import bgl
import blf
import bpy
from bpy_extras import view3d_utils
import math
import mathutils
from bpy.props import (
        BoolProperty,
        EnumProperty,
        FloatProperty,
        IntProperty,
        StringProperty,
        PointerProperty,
        )


# fake fcurve class, used if no fcurve is found for a path
class fake_fcurve():
    def __init__(self, object, index, rotation=False, scale=False):
        # location
        if not rotation and not scale:
            self.loc = object.location[index]
        # scale
        elif scale:
            self.loc = object.scale[index]
        # rotation
        elif rotation == 'QUATERNION':
            self.loc = object.rotation_quaternion[index]
        elif rotation == 'AXIS_ANGLE':
            self.loc = object.rotation_axis_angle[index]
        else:
            self.loc = object.rotation_euler[index]
        self.keyframe_points = []

    def evaluate(self, frame):
        return(self.loc)

    def range(self):
        return([])


# get location curves of the given object
def get_curves(object, child=False):
    if object.animation_data and object.animation_data.action:
        action = object.animation_data.action
        if child:
            # posebone
            curves = [
                    fc for fc in action.fcurves if len(fc.data_path) >= 14 and
                    fc.data_path[-9:] == '.location' and
                    child.name in fc.data_path.split("\"")
                    ]
        else:
            # normal object
            curves = [fc for fc in action.fcurves if fc.data_path == 'location']

    elif object.animation_data and object.animation_data.use_nla:
        curves = []
        strips = []
        for track in object.animation_data.nla_tracks:
            not_handled = [s for s in track.strips]
            while not_handled:
                current_strip = not_handled.pop(-1)
                if current_strip.action:
                    strips.append(current_strip)
                if current_strip.strips:
                    # meta strip
                    not_handled += [s for s in current_strip.strips]

        for strip in strips:
            if child:
                # posebone
                curves = [
                        fc for fc in strip.action.fcurves if
                        len(fc.data_path) >= 14 and fc.data_path[-9:] == '.location' and
                        child.name in fc.data_path.split("\"")
                        ]
            else:
                # normal object
                curves = [fc for fc in strip.action.fcurves if fc.data_path == 'location']
            if curves:
                # use first strip with location fcurves
                break
    else:
        # should not happen?
        curves = []

    # ensure we have three curves per object
    fcx = None
    fcy = None
    fcz = None
    for fc in curves:
        if fc.array_index == 0:
            fcx = fc
        elif fc.array_index == 1:
            fcy = fc
        elif fc.array_index == 2:
            fcz = fc
    if fcx is None:
        fcx = fake_fcurve(object, 0)
    if fcy is None:
        fcy = fake_fcurve(object, 1)
    if fcz is None:
        fcz = fake_fcurve(object, 2)

    return([fcx, fcy, fcz])


# turn screen coordinates (x,y) into world coordinates vector
def screen_to_world(context, x, y):
    depth_vector = view3d_utils.region_2d_to_vector_3d(
                            context.region, context.region_data, [x, y]
                            )
    vector = view3d_utils.region_2d_to_location_3d(
                            context.region, context.region_data, [x, y],
                            depth_vector
                            )

    return(vector)


# turn 3d world coordinates vector into screen coordinate integers (x,y)
def world_to_screen(context, vector):
    prj = context.region_data.perspective_matrix * \
        mathutils.Vector((vector[0], vector[1], vector[2], 1.0))
    width_half = context.region.width / 2.0
    height_half = context.region.height / 2.0

    x = int(width_half + width_half * (prj.x / prj.w))
    y = int(height_half + height_half * (prj.y / prj.w))

    # correction for corner cases in perspective mode
    if prj.w < 0:
        if x < 0:
            x = context.region.width * 2
        else:
            x = context.region.width * -2
        if y < 0:
            y = context.region.height * 2
        else:
            y = context.region.height * -2

    return(x, y)


# calculate location of display_ob in worldspace
def get_location(frame, display_ob, offset_ob, curves):
    if offset_ob:
        bpy.context.scene.frame_set(frame)
        display_mat = getattr(display_ob, "matrix", False)
        if not display_mat:
            # posebones have "matrix", objects have "matrix_world"
            display_mat = display_ob.matrix_world
        if offset_ob:
            loc = display_mat.to_translation() + \
                offset_ob.matrix_world.to_translation()
        else:
            loc = display_mat.to_translation()
    else:
        fcx, fcy, fcz = curves
        locx = fcx.evaluate(frame)
        locy = fcy.evaluate(frame)
        locz = fcz.evaluate(frame)
        loc = mathutils.Vector([locx, locy, locz])

    return(loc)


# get position of keyframes and handles at the start of dragging
def get_original_animation_data(context, keyframes):
    keyframes_ori = {}
    handles_ori = {}

    if context.active_object and context.active_object.mode == 'POSE':
        armature_ob = context.active_object
        objects = [[armature_ob, pb, armature_ob] for pb in
                    context.selected_pose_bones]
    else:
        objects = [[ob, False, False] for ob in context.selected_objects]

    for action_ob, child, offset_ob in objects:
        if not action_ob.animation_data:
            continue
        curves = get_curves(action_ob, child)
        if len(curves) == 0:
            continue
        fcx, fcy, fcz = curves
        if child:
            display_ob = child
        else:
            display_ob = action_ob

        # get keyframe positions
        frame_old = context.scene.frame_current
        keyframes_ori[display_ob.name] = {}
        for frame in keyframes[display_ob.name]:
            loc = get_location(frame, display_ob, offset_ob, curves)
            keyframes_ori[display_ob.name][frame] = [frame, loc]

        # get handle positions
        handles_ori[display_ob.name] = {}
        for frame in keyframes[display_ob.name]:
            handles_ori[display_ob.name][frame] = {}
            left_x = [frame, fcx.evaluate(frame)]
            right_x = [frame, fcx.evaluate(frame)]
            for kf in fcx.keyframe_points:
                if kf.co[0] == frame:
                    left_x = kf.handle_left[:]
                    right_x = kf.handle_right[:]
                    break
            left_y = [frame, fcy.evaluate(frame)]
            right_y = [frame, fcy.evaluate(frame)]
            for kf in fcy.keyframe_points:
                if kf.co[0] == frame:
                    left_y = kf.handle_left[:]
                    right_y = kf.handle_right[:]
                    break
            left_z = [frame, fcz.evaluate(frame)]
            right_z = [frame, fcz.evaluate(frame)]
            for kf in fcz.keyframe_points:
                if kf.co[0] == frame:
                    left_z = kf.handle_left[:]
                    right_z = kf.handle_right[:]
                    break
            handles_ori[display_ob.name][frame]["left"] = [left_x, left_y,
                left_z]
            handles_ori[display_ob.name][frame]["right"] = [right_x, right_y,
                right_z]

        if context.scene.frame_current != frame_old:
            context.scene.frame_set(frame_old)

    return(keyframes_ori, handles_ori)


# callback function that calculates positions of all things that need be drawn
def calc_callback(self, context):
    if context.active_object and context.active_object.mode == 'POSE':
        armature_ob = context.active_object
        objects = [
                [armature_ob, pb, armature_ob] for pb in
                context.selected_pose_bones
                ]
    else:
        objects = [[ob, False, False] for ob in context.selected_objects]
    if objects == self.displayed:
        selection_change = False
    else:
        selection_change = True

    if self.lock and not selection_change and \
    context.region_data.perspective_matrix == self.perspective and not \
    context.window_manager.motion_trail.force_update:
        return

    # dictionaries with key: objectname
    self.paths = {}      # value: list of lists with x, y, color
    self.keyframes = {}  # value: dict with frame as key and [x,y] as value
    self.handles = {}    # value: dict of dicts
    self.timebeads = {}  # value: dict with frame as key and [x,y] as value
    self.click = {}      # value: list of lists with frame, type, loc-vector
    if selection_change:
        # value: editbone inverted rotation matrix or None
        self.edit_bones = {}
    if selection_change or not self.lock or context.window_manager.\
    motion_trail.force_update:
        # contains locations of path, keyframes and timebeads
        self.cached = {
                "path": {}, "keyframes": {}, "timebeads_timing": {},
                "timebeads_speed": {}
                }
    if self.cached["path"]:
        use_cache = True
    else:
        use_cache = False
    self.perspective = context.region_data.perspective_matrix.copy()
    self.displayed = objects  # store, so it can be checked next time
    context.window_manager.motion_trail.force_update = False
    try:
        global_undo = context.preferences.edit.use_global_undo
        context.preferences.edit.use_global_undo = False

        for action_ob, child, offset_ob in objects:
            if selection_change:
                if not child:
                    self.edit_bones[action_ob.name] = None
                else:
                    bpy.ops.object.mode_set(mode='EDIT')
                    editbones = action_ob.data.edit_bones
                    mat = editbones[child.name].matrix.copy().to_3x3().inverted()
                    bpy.ops.object.mode_set(mode='POSE')
                    self.edit_bones[child.name] = mat

            if not action_ob.animation_data:
                continue
            curves = get_curves(action_ob, child)
            if len(curves) == 0:
                continue

            if context.window_manager.motion_trail.path_before == 0:
                range_min = context.scene.frame_start
            else:
                range_min = max(
                            context.scene.frame_start,
                            context.scene.frame_current -
                            context.window_manager.motion_trail.path_before
                            )
            if context.window_manager.motion_trail.path_after == 0:
                range_max = context.scene.frame_end
            else:
                range_max = min(context.scene.frame_end,
                            context.scene.frame_current +
                            context.window_manager.motion_trail.path_after
                            )
            fcx, fcy, fcz = curves
            if child:
                display_ob = child
            else:
                display_ob = action_ob

            # get location data of motion path
            path = []
            speeds = []
            frame_old = context.scene.frame_current
            step = 11 - context.window_manager.motion_trail.path_resolution

            if not use_cache:
                if display_ob.name not in self.cached["path"]:
                    self.cached["path"][display_ob.name] = {}
            if use_cache and range_min - 1 in self.cached["path"][display_ob.name]:
                prev_loc = self.cached["path"][display_ob.name][range_min - 1]
            else:
                prev_loc = get_location(range_min - 1, display_ob, offset_ob, curves)
                self.cached["path"][display_ob.name][range_min - 1] = prev_loc

            for frame in range(range_min, range_max + 1, step):
                if use_cache and frame in self.cached["path"][display_ob.name]:
                    loc = self.cached["path"][display_ob.name][frame]
                else:
                    loc = get_location(frame, display_ob, offset_ob, curves)
                    self.cached["path"][display_ob.name][frame] = loc
                if not context.region or not context.space_data:
                    continue
                x, y = world_to_screen(context, loc)
                if context.window_manager.motion_trail.path_style == 'simple':
                    path.append([x, y, [0.0, 0.0, 0.0], frame, action_ob, child])
                else:
                    dloc = (loc - prev_loc).length
                    path.append([x, y, dloc, frame, action_ob, child])
                    speeds.append(dloc)
                    prev_loc = loc

            # calculate color of path
            if context.window_manager.motion_trail.path_style == 'speed':
                speeds.sort()
                min_speed = speeds[0]
                d_speed = speeds[-1] - min_speed
                for i, [x, y, d_loc, frame, action_ob, child] in enumerate(path):
                    relative_speed = (d_loc - min_speed) / d_speed  # 0.0 to 1.0
                    red = min(1.0, 2.0 * relative_speed)
                    blue = min(1.0, 2.0 - (2.0 * relative_speed))
                    path[i][2] = [red, 0.0, blue]
            elif context.window_manager.motion_trail.path_style == 'acceleration':
                accelerations = []
                prev_speed = 0.0
                for i, [x, y, d_loc, frame, action_ob, child] in enumerate(path):
                    accel = d_loc - prev_speed
                    accelerations.append(accel)
                    path[i][2] = accel
                    prev_speed = d_loc
                accelerations.sort()
                min_accel = accelerations[0]
                max_accel = accelerations[-1]
                for i, [x, y, accel, frame, action_ob, child] in enumerate(path):
                    if accel < 0:
                        relative_accel = accel / min_accel  # values from 0.0 to 1.0
                        green = 1.0 - relative_accel
                        path[i][2] = [1.0, green, 0.0]
                    elif accel > 0:
                        relative_accel = accel / max_accel  # values from 0.0 to 1.0
                        red = 1.0 - relative_accel
                        path[i][2] = [red, 1.0, 0.0]
                    else:
                        path[i][2] = [1.0, 1.0, 0.0]
            self.paths[display_ob.name] = path

            # get keyframes and handles
            keyframes = {}
            handle_difs = {}
            kf_time = []
            click = []
            if not use_cache:
                if display_ob.name not in self.cached["keyframes"]:
                    self.cached["keyframes"][display_ob.name] = {}

            for fc in curves:
                for kf in fc.keyframe_points:
                    # handles for location mode
                    if context.window_manager.motion_trail.mode == 'location':
                        if kf.co[0] not in handle_difs:
                            handle_difs[kf.co[0]] = {"left": mathutils.Vector(),
                                "right": mathutils.Vector(), "keyframe_loc": None}
                        handle_difs[kf.co[0]]["left"][fc.array_index] = \
                            (mathutils.Vector(kf.handle_left[:]) -
                            mathutils.Vector(kf.co[:])).normalized()[1]
                        handle_difs[kf.co[0]]["right"][fc.array_index] = \
                            (mathutils.Vector(kf.handle_right[:]) -
                            mathutils.Vector(kf.co[:])).normalized()[1]
                    # keyframes
                    if kf.co[0] in kf_time:
                        continue
                    kf_time.append(kf.co[0])
                    co = kf.co[0]

                    if use_cache and co in \
                    self.cached["keyframes"][display_ob.name]:
                        loc = self.cached["keyframes"][display_ob.name][co]
                    else:
                        loc = get_location(co, display_ob, offset_ob, curves)
                        self.cached["keyframes"][display_ob.name][co] = loc
                    if handle_difs:
                        handle_difs[co]["keyframe_loc"] = loc

                    x, y = world_to_screen(context, loc)
                    keyframes[kf.co[0]] = [x, y]
                    if context.window_manager.motion_trail.mode != 'speed':
                        # can't select keyframes in speed mode
                        click.append([kf.co[0], "keyframe",
                            mathutils.Vector([x, y]), action_ob, child])
            self.keyframes[display_ob.name] = keyframes

            # handles are only shown in location-altering mode
            if context.window_manager.motion_trail.mode == 'location' and \
            context.window_manager.motion_trail.handle_display:
                # calculate handle positions
                handles = {}
                for frame, vecs in handle_difs.items():
                    if child:
                        # bone space to world space
                        mat = self.edit_bones[child.name].copy().inverted()
                        vec_left = vecs["left"] * mat
                        vec_right = vecs["right"] * mat
                    else:
                        vec_left = vecs["left"]
                        vec_right = vecs["right"]
                    if vecs["keyframe_loc"] is not None:
                        vec_keyframe = vecs["keyframe_loc"]
                    else:
                        vec_keyframe = get_location(frame, display_ob, offset_ob,
                            curves)
                    x_left, y_left = world_to_screen(
                                            context, vec_left * 2 + vec_keyframe
                                            )
                    x_right, y_right = world_to_screen(
                                            context, vec_right * 2 + vec_keyframe
                                            )
                    handles[frame] = {"left": [x_left, y_left],
                                    "right": [x_right, y_right]}
                    click.append([frame, "handle_left",
                        mathutils.Vector([x_left, y_left]), action_ob, child])
                    click.append([frame, "handle_right",
                        mathutils.Vector([x_right, y_right]), action_ob, child])
                self.handles[display_ob.name] = handles

            # calculate timebeads for timing mode
            if context.window_manager.motion_trail.mode == 'timing':
                timebeads = {}
                n = context.window_manager.motion_trail.timebeads * (len(kf_time) - 1)
                dframe = (range_max - range_min) / (n + 1)
                if not use_cache:
                    if display_ob.name not in self.cached["timebeads_timing"]:
                        self.cached["timebeads_timing"][display_ob.name] = {}

                for i in range(1, n + 1):
                    frame = range_min + i * dframe
                    if use_cache and frame in \
                            self.cached["timebeads_timing"][display_ob.name]:
                        loc = self.cached["timebeads_timing"][display_ob.name][frame]
                    else:
                        loc = get_location(frame, display_ob, offset_ob, curves)
                        self.cached["timebeads_timing"][display_ob.name][frame] = loc
                    x, y = world_to_screen(context, loc)
                    timebeads[frame] = [x, y]
                    click.append(
                            [frame, "timebead", mathutils.Vector([x, y]),
                            action_ob, child]
                            )
                self.timebeads[display_ob.name] = timebeads

            # calculate timebeads for speed mode
            if context.window_manager.motion_trail.mode == 'speed':
                angles = dict([[kf, {"left": [], "right": []}] for kf in
                              self.keyframes[display_ob.name]])
                for fc in curves:
                    for i, kf in enumerate(fc.keyframe_points):
                        if i != 0:
                            angle = mathutils.Vector([-1, 0]).angle(
                                                mathutils.Vector(kf.handle_left) -
                                                mathutils.Vector(kf.co), 0
                                                )
                            if angle != 0:
                                angles[kf.co[0]]["left"].append(angle)
                        if i != len(fc.keyframe_points) - 1:
                            angle = mathutils.Vector([1, 0]).angle(
                                                mathutils.Vector(kf.handle_right) -
                                                mathutils.Vector(kf.co), 0
                                                )
                            if angle != 0:
                                angles[kf.co[0]]["right"].append(angle)
                timebeads = {}
                kf_time.sort()
                if not use_cache:
                    if display_ob.name not in self.cached["timebeads_speed"]:
                        self.cached["timebeads_speed"][display_ob.name] = {}

                for frame, sides in angles.items():
                    if sides["left"]:
                        perc = (sum(sides["left"]) / len(sides["left"])) / \
                            (math.pi / 2)
                        perc = max(0.4, min(1, perc * 5))
                        previous = kf_time[kf_time.index(frame) - 1]
                        bead_frame = frame - perc * ((frame - previous - 2) / 2)
                        if use_cache and bead_frame in \
                        self.cached["timebeads_speed"][display_ob.name]:
                            loc = self.cached["timebeads_speed"][display_ob.name][bead_frame]
                        else:
                            loc = get_location(bead_frame, display_ob, offset_ob,
                                curves)
                            self.cached["timebeads_speed"][display_ob.name][bead_frame] = loc
                        x, y = world_to_screen(context, loc)
                        timebeads[bead_frame] = [x, y]
                        click.append(
                                [bead_frame, "timebead",
                                mathutils.Vector([x, y]),
                                action_ob, child]
                                )
                    if sides["right"]:
                        perc = (sum(sides["right"]) / len(sides["right"])) / \
                            (math.pi / 2)
                        perc = max(0.4, min(1, perc * 5))
                        next = kf_time[kf_time.index(frame) + 1]
                        bead_frame = frame + perc * ((next - frame - 2) / 2)
                        if use_cache and bead_frame in \
                        self.cached["timebeads_speed"][display_ob.name]:
                            loc = self.cached["timebeads_speed"][display_ob.name][bead_frame]
                        else:
                            loc = get_location(bead_frame, display_ob, offset_ob,
                                curves)
                            self.cached["timebeads_speed"][display_ob.name][bead_frame] = loc
                        x, y = world_to_screen(context, loc)
                        timebeads[bead_frame] = [x, y]
                        click.append(
                                [bead_frame, "timebead",
                                mathutils.Vector([x, y]),
                                action_ob, child]
                                )
                self.timebeads[display_ob.name] = timebeads

            # add frame positions to click-list
            if context.window_manager.motion_trail.frame_display:
                path = self.paths[display_ob.name]
                for x, y, color, frame, action_ob, child in path:
                    click.append(
                            [frame, "frame",
                            mathutils.Vector([x, y]),
                            action_ob, child]
                            )

            self.click[display_ob.name] = click

            if context.scene.frame_current != frame_old:
                context.scene.frame_set(frame_old)

        context.preferences.edit.use_global_undo = global_undo

    except:
        # restore global undo in case of failure (see T52524)
        context.preferences.edit.use_global_undo = global_undo


# draw in 3d-view
def draw_callback(self, context):
    # polling
    if (context.mode not in ('OBJECT', 'POSE') or
            not context.window_manager.motion_trail.enabled):
        return

    # display limits
    if context.window_manager.motion_trail.path_before != 0:
        limit_min = context.scene.frame_current - \
            context.window_manager.motion_trail.path_before
    else:
        limit_min = -1e6
    if context.window_manager.motion_trail.path_after != 0:
        limit_max = context.scene.frame_current + \
            context.window_manager.motion_trail.path_after
    else:
        limit_max = 1e6

    # draw motion path
    bgl.glEnable(bgl.GL_BLEND)
    bgl.glLineWidth(context.window_manager.motion_trail.path_width)
    alpha = 1.0 - (context.window_manager.motion_trail.path_transparency / 100.0)

    if context.window_manager.motion_trail.path_style == 'simple':
        bgl.glColor4f(0.0, 0.0, 0.0, alpha)
        for objectname, path in self.paths.items():
            bgl.glBegin(bgl.GL_LINE_STRIP)
            for x, y, color, frame, action_ob, child in path:
                if frame < limit_min or frame > limit_max:
                    continue
                bgl.glVertex2i(x, y)
            bgl.glEnd()
    else:
        for objectname, path in self.paths.items():
            for i, [x, y, color, frame, action_ob, child] in enumerate(path):
                if frame < limit_min or frame > limit_max:
                    continue
                r, g, b = color
                if i != 0:
                    prev_path = path[i - 1]
                    halfway = [(x + prev_path[0]) / 2, (y + prev_path[1]) / 2]
                    bgl.glColor4f(r, g, b, alpha)
                    bgl.glBegin(bgl.GL_LINE_STRIP)
                    bgl.glVertex2i(int(halfway[0]), int(halfway[1]))
                    bgl.glVertex2i(x, y)
                    bgl.glEnd()
                if i != len(path) - 1:
                    next_path = path[i + 1]
                    halfway = [(x + next_path[0]) / 2, (y + next_path[1]) / 2]
                    bgl.glColor4f(r, g, b, alpha)
                    bgl.glBegin(bgl.GL_LINE_STRIP)
                    bgl.glVertex2i(x, y)
                    bgl.glVertex2i(int(halfway[0]), int(halfway[1]))
                    bgl.glEnd()

    # draw frames
    if context.window_manager.motion_trail.frame_display:
        bgl.glColor4f(1.0, 1.0, 1.0, 1.0)
        bgl.glPointSize(1)
        bgl.glBegin(bgl.GL_POINTS)
        for objectname, path in self.paths.items():
            for x, y, color, frame, action_ob, child in path:
                if frame < limit_min or frame > limit_max:
                    continue
                if self.active_frame and objectname == self.active_frame[0] \
                and abs(frame - self.active_frame[1]) < 1e-4:
                    bgl.glEnd()
                    bgl.glColor4f(1.0, 0.5, 0.0, 1.0)
                    bgl.glPointSize(3)
                    bgl.glBegin(bgl.GL_POINTS)
                    bgl.glVertex2i(x, y)
                    bgl.glEnd()
                    bgl.glColor4f(1.0, 1.0, 1.0, 1.0)
                    bgl.glPointSize(1)
                    bgl.glBegin(bgl.GL_POINTS)
                else:
                    bgl.glVertex2i(x, y)
        bgl.glEnd()

    # time beads are shown in speed and timing modes
    if context.window_manager.motion_trail.mode in ('speed', 'timing'):
        bgl.glColor4f(0.0, 1.0, 0.0, 1.0)
        bgl.glPointSize(4)
        bgl.glBegin(bgl.GL_POINTS)
        for objectname, values in self.timebeads.items():
            for frame, coords in values.items():
                if frame < limit_min or frame > limit_max:
                    continue
                if self.active_timebead and \
                objectname == self.active_timebead[0] and \
                abs(frame - self.active_timebead[1]) < 1e-4:
                    bgl.glEnd()
                    bgl.glColor4f(1.0, 0.5, 0.0, 1.0)
                    bgl.glBegin(bgl.GL_POINTS)
                    bgl.glVertex2i(coords[0], coords[1])
                    bgl.glEnd()
                    bgl.glColor4f(0.0, 1.0, 0.0, 1.0)
                    bgl.glBegin(bgl.GL_POINTS)
                else:
                    bgl.glVertex2i(coords[0], coords[1])
        bgl.glEnd()

    # handles are only shown in location mode
    if context.window_manager.motion_trail.mode == 'location':
        # draw handle-lines
        bgl.glColor4f(0.0, 0.0, 0.0, 1.0)
        bgl.glLineWidth(1)
        bgl.glBegin(bgl.GL_LINES)
        for objectname, values in self.handles.items():
            for frame, sides in values.items():
                if frame < limit_min or frame > limit_max:
                    continue
                for side, coords in sides.items():
                    if self.active_handle and \
                    objectname == self.active_handle[0] and \
                    side == self.active_handle[2] and \
                    abs(frame - self.active_handle[1]) < 1e-4:
                        bgl.glEnd()
                        bgl.glColor4f(.75, 0.25, 0.0, 1.0)
                        bgl.glBegin(bgl.GL_LINES)
                        bgl.glVertex2i(self.keyframes[objectname][frame][0],
                            self.keyframes[objectname][frame][1])
                        bgl.glVertex2i(coords[0], coords[1])
                        bgl.glEnd()
                        bgl.glColor4f(0.0, 0.0, 0.0, 1.0)
                        bgl.glBegin(bgl.GL_LINES)
                    else:
                        bgl.glVertex2i(self.keyframes[objectname][frame][0],
                            self.keyframes[objectname][frame][1])
                        bgl.glVertex2i(coords[0], coords[1])
        bgl.glEnd()

        # draw handles
        bgl.glColor4f(1.0, 1.0, 0.0, 1.0)
        bgl.glPointSize(4)
        bgl.glBegin(bgl.GL_POINTS)
        for objectname, values in self.handles.items():
            for frame, sides in values.items():
                if frame < limit_min or frame > limit_max:
                    continue
                for side, coords in sides.items():
                    if self.active_handle and \
                    objectname == self.active_handle[0] and \
                    side == self.active_handle[2] and \
                    abs(frame - self.active_handle[1]) < 1e-4:
                        bgl.glEnd()
                        bgl.glColor4f(1.0, 0.5, 0.0, 1.0)
                        bgl.glBegin(bgl.GL_POINTS)
                        bgl.glVertex2i(coords[0], coords[1])
                        bgl.glEnd()
                        bgl.glColor4f(1.0, 1.0, 0.0, 1.0)
                        bgl.glBegin(bgl.GL_POINTS)
                    else:
                        bgl.glVertex2i(coords[0], coords[1])
        bgl.glEnd()

    # draw keyframes
    bgl.glColor4f(1.0, 1.0, 0.0, 1.0)
    bgl.glPointSize(6)
    bgl.glBegin(bgl.GL_POINTS)
    for objectname, values in self.keyframes.items():
        for frame, coords in values.items():
            if frame < limit_min or frame > limit_max:
                continue
            if self.active_keyframe and \
            objectname == self.active_keyframe[0] and \
            abs(frame - self.active_keyframe[1]) < 1e-4:
                bgl.glEnd()
                bgl.glColor4f(1.0, 0.5, 0.0, 1.0)
                bgl.glBegin(bgl.GL_POINTS)
                bgl.glVertex2i(coords[0], coords[1])
                bgl.glEnd()
                bgl.glColor4f(1.0, 1.0, 0.0, 1.0)
                bgl.glBegin(bgl.GL_POINTS)
            else:
                bgl.glVertex2i(coords[0], coords[1])
    bgl.glEnd()

    # draw keyframe-numbers
    if context.window_manager.motion_trail.keyframe_numbers:
        blf.size(0, 12, 72)
        bgl.glColor4f(1.0, 1.0, 0.0, 1.0)
        for objectname, values in self.keyframes.items():
            for frame, coords in values.items():
                if frame < limit_min or frame > limit_max:
                    continue
                blf.position(0, coords[0] + 3, coords[1] + 3, 0)
                text = str(frame).split(".")
                if len(text) == 1:
                    text = text[0]
                elif len(text[1]) == 1 and text[1] == "0":
                    text = text[0]
                else:
                    text = text[0] + "." + text[1][0]
                if self.active_keyframe and \
                objectname == self.active_keyframe[0] and \
                abs(frame - self.active_keyframe[1]) < 1e-4:
                    bgl.glColor4f(1.0, 0.5, 0.0, 1.0)
                    blf.draw(0, text)
                    bgl.glColor4f(1.0, 1.0, 0.0, 1.0)
                else:
                    blf.draw(0, text)

    # restore opengl defaults
    bgl.glLineWidth(1)
    bgl.glDisable(bgl.GL_BLEND)
    bgl.glColor4f(0.0, 0.0, 0.0, 1.0)
    bgl.glPointSize(1)


# change data based on mouse movement
def drag(context, event, drag_mouse_ori, active_keyframe, active_handle,
active_timebead, keyframes_ori, handles_ori, edit_bones):
    # change 3d-location of keyframe
    if context.window_manager.motion_trail.mode == 'location' and \
    active_keyframe:
        objectname, frame, frame_ori, action_ob, child = active_keyframe
        if child:
            mat = action_ob.matrix_world.copy().inverted() * \
                edit_bones[child.name].copy().to_4x4()
        else:
            mat = 1

        mouse_ori_world = screen_to_world(context, drag_mouse_ori[0],
            drag_mouse_ori[1]) * mat
        vector = screen_to_world(context, event.mouse_region_x,
            event.mouse_region_y) * mat
        d = vector - mouse_ori_world

        loc_ori_ws = keyframes_ori[objectname][frame][1]
        loc_ori_bs = loc_ori_ws * mat
        new_loc = loc_ori_bs + d
        curves = get_curves(action_ob, child)

        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if kf.co[0] == frame:
                    kf.co[1] = new_loc[i]
                    kf.handle_left[1] = handles_ori[objectname][frame]["left"][i][1] + d[i]
                    kf.handle_right[1] = handles_ori[objectname][frame]["right"][i][1] + d[i]
                    break

    # change 3d-location of handle
    elif context.window_manager.motion_trail.mode == 'location' and active_handle:
        objectname, frame, side, action_ob, child = active_handle
        if child:
            mat = action_ob.matrix_world.copy().inverted() * \
                edit_bones[child.name].copy().to_4x4()
        else:
            mat = 1

        mouse_ori_world = screen_to_world(context, drag_mouse_ori[0],
            drag_mouse_ori[1]) * mat
        vector = screen_to_world(context, event.mouse_region_x,
            event.mouse_region_y) * mat
        d = vector - mouse_ori_world
        curves = get_curves(action_ob, child)

        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if kf.co[0] == frame:
                    if side == "left":
                        # change handle type, if necessary
                        if kf.handle_left_type in (
                                'AUTO',
                                'AUTO_CLAMPED',
                                'ANIM_CLAMPED'):
                            kf.handle_left_type = 'ALIGNED'
                        elif kf.handle_left_type == 'VECTOR':
                            kf.handle_left_type = 'FREE'
                        # change handle position(s)
                        kf.handle_left[1] = handles_ori[objectname][frame]["left"][i][1] + d[i]
                        if kf.handle_left_type in (
                                'ALIGNED',
                                'ANIM_CLAMPED',
                                'AUTO',
                                'AUTO_CLAMPED'):
                            dif = (
                                abs(handles_ori[objectname][frame]["right"][i][0] -
                                kf.co[0]) / abs(kf.handle_left[0] -
                                kf.co[0])
                                ) * d[i]
                            kf.handle_right[1] = handles_ori[objectname][frame]["right"][i][1] - dif
                    elif side == "right":
                        # change handle type, if necessary
                        if kf.handle_right_type in (
                                'AUTO',
                                'AUTO_CLAMPED',
                                'ANIM_CLAMPED'):
                            kf.handle_left_type = 'ALIGNED'
                            kf.handle_right_type = 'ALIGNED'
                        elif kf.handle_right_type == 'VECTOR':
                            kf.handle_left_type = 'FREE'
                            kf.handle_right_type = 'FREE'
                        # change handle position(s)
                        kf.handle_right[1] = handles_ori[objectname][frame]["right"][i][1] + d[i]
                        if kf.handle_right_type in (
                                'ALIGNED',
                                'ANIM_CLAMPED',
                                'AUTO',
                                'AUTO_CLAMPED'):
                            dif = (
                                abs(handles_ori[objectname][frame]["left"][i][0] -
                                kf.co[0]) / abs(kf.handle_right[0] -
                                kf.co[0])
                                ) * d[i]
                            kf.handle_left[1] = handles_ori[objectname][frame]["left"][i][1] - dif
                    break

    # change position of all keyframes on timeline
    elif context.window_manager.motion_trail.mode == 'timing' and \
    active_timebead:
        objectname, frame, frame_ori, action_ob, child = active_timebead
        curves = get_curves(action_ob, child)
        ranges = [val for c in curves for val in c.range()]
        ranges.sort()
        range_min = round(ranges[0])
        range_max = round(ranges[-1])
        range = range_max - range_min
        dx_screen = -(mathutils.Vector([event.mouse_region_x,
            event.mouse_region_y]) - drag_mouse_ori)[0]
        dx_screen = dx_screen / context.region.width * range
        new_frame = frame + dx_screen
        shift_low = max(1e-4, (new_frame - range_min) / (frame - range_min))
        shift_high = max(1e-4, (range_max - new_frame) / (range_max - frame))

        new_mapping = {}
        for i, curve in enumerate(curves):
            for j, kf in enumerate(curve.keyframe_points):
                frame_map = kf.co[0]
                if frame_map < range_min + 1e-4 or \
                frame_map > range_max - 1e-4:
                    continue
                frame_ori = False
                for f in keyframes_ori[objectname]:
                    if abs(f - frame_map) < 1e-4:
                        frame_ori = keyframes_ori[objectname][f][0]
                        value_ori = keyframes_ori[objectname][f]
                        break
                if not frame_ori:
                    continue
                if frame_ori <= frame:
                    frame_new = (frame_ori - range_min) * shift_low + \
                        range_min
                else:
                    frame_new = range_max - (range_max - frame_ori) * \
                        shift_high
                frame_new = max(
                            range_min + j, min(frame_new, range_max -
                            (len(curve.keyframe_points) - j) + 1)
                            )
                d_frame = frame_new - frame_ori
                if frame_new not in new_mapping:
                    new_mapping[frame_new] = value_ori
                kf.co[0] = frame_new
                kf.handle_left[0] = handles_ori[objectname][frame_ori]["left"][i][0] + d_frame
                kf.handle_right[0] = handles_ori[objectname][frame_ori]["right"][i][0] + d_frame
        del keyframes_ori[objectname]
        keyframes_ori[objectname] = {}
        for new_frame, value in new_mapping.items():
            keyframes_ori[objectname][new_frame] = value

    # change position of active keyframe on the timeline
    elif context.window_manager.motion_trail.mode == 'timing' and \
    active_keyframe:
        objectname, frame, frame_ori, action_ob, child = active_keyframe
        if child:
            mat = action_ob.matrix_world.copy().inverted() * \
                edit_bones[child.name].copy().to_4x4()
        else:
            mat = action_ob.matrix_world.copy().inverted()

        mouse_ori_world = screen_to_world(context, drag_mouse_ori[0],
            drag_mouse_ori[1]) * mat
        vector = screen_to_world(context, event.mouse_region_x,
            event.mouse_region_y) * mat
        d = vector - mouse_ori_world

        locs_ori = [[f_ori, coords] for f_mapped, [f_ori, coords] in
                    keyframes_ori[objectname].items()]
        locs_ori.sort()
        direction = 1
        range = False
        for i, [f_ori, coords] in enumerate(locs_ori):
            if abs(frame_ori - f_ori) < 1e-4:
                if i == 0:
                    # first keyframe, nothing before it
                    direction = -1
                    range = [f_ori, locs_ori[i + 1][0]]
                elif i == len(locs_ori) - 1:
                    # last keyframe, nothing after it
                    range = [locs_ori[i - 1][0], f_ori]
                else:
                    current = mathutils.Vector(coords)
                    next = mathutils.Vector(locs_ori[i + 1][1])
                    previous = mathutils.Vector(locs_ori[i - 1][1])
                    angle_to_next = d.angle(next - current, 0)
                    angle_to_previous = d.angle(previous - current, 0)
                    if angle_to_previous < angle_to_next:
                        # mouse movement is in direction of previous keyframe
                        direction = -1
                    range = [locs_ori[i - 1][0], locs_ori[i + 1][0]]
                break
        direction *= -1  # feels more natural in 3d-view
        if not range:
            # keyframe not found, is impossible, but better safe than sorry
            return(active_keyframe, active_timebead, keyframes_ori)
        # calculate strength of movement
        d_screen = mathutils.Vector([event.mouse_region_x,
            event.mouse_region_y]) - drag_mouse_ori
        if d_screen.length != 0:
            d_screen = d_screen.length / (abs(d_screen[0]) / d_screen.length *
                      context.region.width + abs(d_screen[1]) / d_screen.length *
                      context.region.height)
            d_screen *= direction  # d_screen value ranges from -1.0 to 1.0
        else:
            d_screen = 0.0
        new_frame = d_screen * (range[1] - range[0]) + frame_ori
        max_frame = range[1]
        if max_frame == frame_ori:
            max_frame += 1
        min_frame = range[0]
        if min_frame == frame_ori:
            min_frame -= 1
        new_frame = min(max_frame - 1, max(min_frame + 1, new_frame))
        d_frame = new_frame - frame_ori
        curves = get_curves(action_ob, child)

        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if abs(kf.co[0] - frame) < 1e-4:
                    kf.co[0] = new_frame
                    kf.handle_left[0] = handles_ori[objectname][frame_ori]["left"][i][0] + d_frame
                    kf.handle_right[0] = handles_ori[objectname][frame_ori]["right"][i][0] + d_frame
                    break
        active_keyframe = [objectname, new_frame, frame_ori, action_ob, child]

    # change position of active timebead on the timeline, thus altering speed
    elif context.window_manager.motion_trail.mode == 'speed' and \
    active_timebead:
        objectname, frame, frame_ori, action_ob, child = active_timebead
        if child:
            mat = action_ob.matrix_world.copy().inverted() * \
                edit_bones[child.name].copy().to_4x4()
        else:
            mat = 1

        mouse_ori_world = screen_to_world(context, drag_mouse_ori[0],
            drag_mouse_ori[1]) * mat
        vector = screen_to_world(context, event.mouse_region_x,
            event.mouse_region_y) * mat
        d = vector - mouse_ori_world

        # determine direction (to next or previous keyframe)
        curves = get_curves(action_ob, child)
        fcx, fcy, fcz = curves
        locx = fcx.evaluate(frame_ori)
        locy = fcy.evaluate(frame_ori)
        locz = fcz.evaluate(frame_ori)
        loc_ori = mathutils.Vector([locx, locy, locz])  # bonespace
        keyframes = [kf for kf in keyframes_ori[objectname]]
        keyframes.append(frame_ori)
        keyframes.sort()
        frame_index = keyframes.index(frame_ori)
        kf_prev = keyframes[frame_index - 1]
        kf_next = keyframes[frame_index + 1]
        vec_prev = (
                mathutils.Vector(keyframes_ori[objectname][kf_prev][1]) *
                mat - loc_ori
                ).normalized()
        vec_next = (mathutils.Vector(keyframes_ori[objectname][kf_next][1]) *
                mat - loc_ori
                ).normalized()
        d_normal = d.copy().normalized()
        dist_to_next = (d_normal - vec_next).length
        dist_to_prev = (d_normal - vec_prev).length
        if dist_to_prev < dist_to_next:
            direction = 1
        else:
            direction = -1

        if (kf_next - frame_ori) < (frame_ori - kf_prev):
            kf_bead = kf_next
            side = "left"
        else:
            kf_bead = kf_prev
            side = "right"
        d_frame = d.length * direction * 2  # * 2 to make it more sensitive

        angles = []
        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if abs(kf.co[0] - kf_bead) < 1e-4:
                    if side == "left":
                        # left side
                        kf.handle_left[0] = min(
                                            handles_ori[objectname][kf_bead]["left"][i][0] +
                                            d_frame, kf_bead - 1
                                            )
                        angle = mathutils.Vector([-1, 0]).angle(
                                            mathutils.Vector(kf.handle_left) -
                                            mathutils.Vector(kf.co), 0
                                            )
                        if angle != 0:
                            angles.append(angle)
                    else:
                        # right side
                        kf.handle_right[0] = max(
                                            handles_ori[objectname][kf_bead]["right"][i][0] +
                                            d_frame, kf_bead + 1
                                            )
                        angle = mathutils.Vector([1, 0]).angle(
                                            mathutils.Vector(kf.handle_right) -
                                            mathutils.Vector(kf.co), 0
                                            )
                        if angle != 0:
                            angles.append(angle)
                    break

        # update frame of active_timebead
        perc = (sum(angles) / len(angles)) / (math.pi / 2)
        perc = max(0.4, min(1, perc * 5))
        if side == "left":
            bead_frame = kf_bead - perc * ((kf_bead - kf_prev - 2) / 2)
        else:
            bead_frame = kf_bead + perc * ((kf_next - kf_bead - 2) / 2)
        active_timebead = [objectname, bead_frame, frame_ori, action_ob, child]

    return(active_keyframe, active_timebead, keyframes_ori)


# revert changes made by dragging
def cancel_drag(context, active_keyframe, active_handle, active_timebead,
keyframes_ori, handles_ori, edit_bones):
    # revert change in 3d-location of active keyframe and its handles
    if context.window_manager.motion_trail.mode == 'location' and \
    active_keyframe:
        objectname, frame, frame_ori, active_ob, child = active_keyframe
        curves = get_curves(active_ob, child)
        loc_ori = keyframes_ori[objectname][frame][1]
        if child:
            loc_ori = loc_ori * edit_bones[child.name] * \
                active_ob.matrix_world.copy().inverted()
        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if kf.co[0] == frame:
                    kf.co[1] = loc_ori[i]
                    kf.handle_left[1] = handles_ori[objectname][frame]["left"][i][1]
                    kf.handle_right[1] = handles_ori[objectname][frame]["right"][i][1]
                    break

    # revert change in 3d-location of active handle
    elif context.window_manager.motion_trail.mode == 'location' and \
    active_handle:
        objectname, frame, side, active_ob, child = active_handle
        curves = get_curves(active_ob, child)
        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if kf.co[0] == frame:
                    kf.handle_left[1] = handles_ori[objectname][frame]["left"][i][1]
                    kf.handle_right[1] = handles_ori[objectname][frame]["right"][i][1]
                    break

    # revert position of all keyframes and handles on timeline
    elif context.window_manager.motion_trail.mode == 'timing' and \
    active_timebead:
        objectname, frame, frame_ori, active_ob, child = active_timebead
        curves = get_curves(active_ob, child)
        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                for kf_ori, [frame_ori, loc] in keyframes_ori[objectname].\
                items():
                    if abs(kf.co[0] - kf_ori) < 1e-4:
                        kf.co[0] = frame_ori
                        kf.handle_left[0] = handles_ori[objectname][frame_ori]["left"][i][0]
                        kf.handle_right[0] = handles_ori[objectname][frame_ori]["right"][i][0]
                        break

    # revert position of active keyframe and its handles on the timeline
    elif context.window_manager.motion_trail.mode == 'timing' and \
    active_keyframe:
        objectname, frame, frame_ori, active_ob, child = active_keyframe
        curves = get_curves(active_ob, child)
        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if abs(kf.co[0] - frame) < 1e-4:
                    kf.co[0] = keyframes_ori[objectname][frame_ori][0]
                    kf.handle_left[0] = handles_ori[objectname][frame_ori]["left"][i][0]
                    kf.handle_right[0] = handles_ori[objectname][frame_ori]["right"][i][0]
                    break
        active_keyframe = [objectname, frame_ori, frame_ori, active_ob, child]

    # revert position of handles on the timeline
    elif context.window_manager.motion_trail.mode == 'speed' and \
    active_timebead:
        objectname, frame, frame_ori, active_ob, child = active_timebead
        curves = get_curves(active_ob, child)
        keyframes = [kf for kf in keyframes_ori[objectname]]
        keyframes.append(frame_ori)
        keyframes.sort()
        frame_index = keyframes.index(frame_ori)
        kf_prev = keyframes[frame_index - 1]
        kf_next = keyframes[frame_index + 1]
        if (kf_next - frame_ori) < (frame_ori - kf_prev):
            kf_frame = kf_next
        else:
            kf_frame = kf_prev
        for i, curve in enumerate(curves):
            for kf in curve.keyframe_points:
                if kf.co[0] == kf_frame:
                    kf.handle_left[0] = handles_ori[objectname][kf_frame]["left"][i][0]
                    kf.handle_right[0] = handles_ori[objectname][kf_frame]["right"][i][0]
                    break
        active_timebead = [objectname, frame_ori, frame_ori, active_ob, child]

    return(active_keyframe, active_timebead)


# return the handle type of the active selection
def get_handle_type(active_keyframe, active_handle):
    if active_keyframe:
        objectname, frame, side, action_ob, child = active_keyframe
        side = "both"
    elif active_handle:
        objectname, frame, side, action_ob, child = active_handle
    else:
        # no active handle(s)
        return(False)

    # properties used when changing handle type
    bpy.context.window_manager.motion_trail.handle_type_frame = frame
    bpy.context.window_manager.motion_trail.handle_type_side = side
    bpy.context.window_manager.motion_trail.handle_type_action_ob = \
        action_ob.name
    if child:
        bpy.context.window_manager.motion_trail.handle_type_child = child.name
    else:
        bpy.context.window_manager.motion_trail.handle_type_child = ""

    curves = get_curves(action_ob, child=child)
    for c in curves:
        for kf in c.keyframe_points:
            if kf.co[0] == frame:
                if side in ("left", "both"):
                    return(kf.handle_left_type)
                else:
                    return(kf.handle_right_type)

    return("AUTO")


# turn the given frame into a keyframe
def insert_keyframe(self, context, frame):
    objectname, frame, frame, action_ob, child = frame
    curves = get_curves(action_ob, child)
    for c in curves:
        y = c.evaluate(frame)
        if c.keyframe_points:
            c.keyframe_points.insert(frame, y)

    bpy.context.window_manager.motion_trail.force_update = True
    calc_callback(self, context)


# change the handle type of the active selection
def set_handle_type(self, context):
    if not context.window_manager.motion_trail.handle_type_enabled:
        return
    if context.window_manager.motion_trail.handle_type_old == \
    context.window_manager.motion_trail.handle_type:
        # function called because of selection change, not change in type
        return
    context.window_manager.motion_trail.handle_type_old = \
        context.window_manager.motion_trail.handle_type

    frame = bpy.context.window_manager.motion_trail.handle_type_frame
    side = bpy.context.window_manager.motion_trail.handle_type_side
    action_ob = bpy.context.window_manager.motion_trail.handle_type_action_ob
    action_ob = bpy.data.objects[action_ob]
    child = bpy.context.window_manager.motion_trail.handle_type_child
    if child:
        child = action_ob.pose.bones[child]
    new_type = context.window_manager.motion_trail.handle_type

    curves = get_curves(action_ob, child=child)
    for c in curves:
        for kf in c.keyframe_points:
            if kf.co[0] == frame:
                # align if necessary
                if side in ("right", "both") and new_type in (
                            "AUTO", "AUTO_CLAMPED", "ALIGNED"):
                    # change right handle
                    normal = (kf.co - kf.handle_left).normalized()
                    size = (kf.handle_right[0] - kf.co[0]) / normal[0]
                    normal = normal * size + kf.co
                    kf.handle_right[1] = normal[1]
                elif side == "left" and new_type in (
                            "AUTO", "AUTO_CLAMPED", "ALIGNED"):
                    # change left handle
                    normal = (kf.co - kf.handle_right).normalized()
                    size = (kf.handle_left[0] - kf.co[0]) / normal[0]
                    normal = normal * size + kf.co
                    kf.handle_left[1] = normal[1]
                # change type
                if side in ("left", "both"):
                    kf.handle_left_type = new_type
                if side in ("right", "both"):
                    kf.handle_right_type = new_type

    context.window_manager.motion_trail.force_update = True


class MotionTrailOperator(bpy.types.Operator):
    bl_idname = "view3d.motion_trail"
    bl_label = "Motion Trail"
    bl_description = "Edit motion trails in 3d-view"

    _handle_calc = None
    _handle_draw = None

    @staticmethod
    def handle_add(self, context):
        MotionTrailOperator._handle_calc = bpy.types.SpaceView3D.draw_handler_add(
            calc_callback, (self, context), 'WINDOW', 'POST_VIEW')
        MotionTrailOperator._handle_draw = bpy.types.SpaceView3D.draw_handler_add(
            draw_callback, (self, context), 'WINDOW', 'POST_PIXEL')

    @staticmethod
    def handle_remove():
        if MotionTrailOperator._handle_calc is not None:
            bpy.types.SpaceView3D.draw_handler_remove(MotionTrailOperator._handle_calc, 'WINDOW')
        if MotionTrailOperator._handle_draw is not None:
            bpy.types.SpaceView3D.draw_handler_remove(MotionTrailOperator._handle_draw, 'WINDOW')
        MotionTrailOperator._handle_calc = None
        MotionTrailOperator._handle_draw = None

    def modal(self, context, event):
        # XXX Required, or custom transform.translate will break!
        # XXX If one disables and re-enables motion trail, modal op will still be running,
        # XXX default translate op will unintentionally get called, followed by custom translate.
        if not context.window_manager.motion_trail.enabled:
            MotionTrailOperator.handle_remove()
            context.area.tag_redraw()
            return {'FINISHED'}

        if not context.area or not context.region or event.type == 'NONE':
            context.area.tag_redraw()
            return {'PASS_THROUGH'}

        wm = context.window_manager
        keyconfig = wm.keyconfigs.active
        select = getattr(keyconfig.preferences, "select_mouse", "LEFT")

        if (not context.active_object or
                context.active_object.mode not in ('OBJECT', 'POSE')):
            if self.drag:
                self.drag = False
                self.lock = True
                context.window_manager.motion_trail.force_update = True
            # default hotkeys should still work
            if event.type == self.transform_key and event.value == 'PRESS':
                if bpy.ops.transform.translate.poll():
                    bpy.ops.transform.translate('INVOKE_DEFAULT')
            elif event.type == select + 'MOUSE' and event.value == 'PRESS' \
            and not self.drag and not event.shift and not event.alt \
            and not event.ctrl:
                if bpy.ops.view3d.select.poll():
                    bpy.ops.view3d.select('INVOKE_DEFAULT')
            elif event.type == 'LEFTMOUSE' and event.value == 'PRESS' and not\
            event.alt and not event.ctrl and not event.shift:
                if eval("bpy.ops." + self.left_action + ".poll()"):
                    eval("bpy.ops." + self.left_action + "('INVOKE_DEFAULT')")
            return {'PASS_THROUGH'}
        # check if event was generated within 3d-window, dragging is exception
        if not self.drag:
            if not (0 < event.mouse_region_x < context.region.width) or \
            not (0 < event.mouse_region_y < context.region.height):
                return {'PASS_THROUGH'}

        if (event.type == self.transform_key and event.value == 'PRESS' and
               (self.active_keyframe or
                self.active_handle or
                self.active_timebead or
                self.active_frame)):
            # override default translate()
            if not self.drag:
                # start drag
                if self.active_frame:
                    insert_keyframe(self, context, self.active_frame)
                    self.active_keyframe = self.active_frame
                    self.active_frame = False
                self.keyframes_ori, self.handles_ori = \
                    get_original_animation_data(context, self.keyframes)
                self.drag_mouse_ori = mathutils.Vector([event.mouse_region_x,
                    event.mouse_region_y])
                self.drag = True
                self.lock = False
            else:
                # stop drag
                self.drag = False
                self.lock = True
                context.window_manager.motion_trail.force_update = True
        elif event.type == self.transform_key and event.value == 'PRESS':
            # call default translate()
            if bpy.ops.transform.translate.poll():
                bpy.ops.transform.translate('INVOKE_DEFAULT')
        elif (event.type == 'ESC' and self.drag and event.value == 'PRESS') or \
             (event.type == 'RIGHTMOUSE' and self.drag and event.value == 'PRESS'):
            # cancel drag
            self.drag = False
            self.lock = True
            context.window_manager.motion_trail.force_update = True
            self.active_keyframe, self.active_timebead = cancel_drag(context,
                self.active_keyframe, self.active_handle,
                self.active_timebead, self.keyframes_ori, self.handles_ori,
                self.edit_bones)
        elif event.type == 'MOUSEMOVE' and self.drag:
            # drag
            self.active_keyframe, self.active_timebead, self.keyframes_ori = \
                drag(context, event, self.drag_mouse_ori,
                self.active_keyframe, self.active_handle,
                self.active_timebead, self.keyframes_ori, self.handles_ori,
                self.edit_bones)
        elif event.type == select + 'MOUSE' and event.value == 'PRESS' and \
        not self.drag and not event.shift and not event.alt and not \
        event.ctrl:
            # select
            treshold = 10
            clicked = mathutils.Vector([event.mouse_region_x,
                event.mouse_region_y])
            self.active_keyframe = False
            self.active_handle = False
            self.active_timebead = False
            self.active_frame = False
            context.window_manager.motion_trail.force_update = True
            context.window_manager.motion_trail.handle_type_enabled = True
            found = False

            if context.window_manager.motion_trail.path_before == 0:
                frame_min = context.scene.frame_start
            else:
                frame_min = max(
                            context.scene.frame_start,
                            context.scene.frame_current -
                            context.window_manager.motion_trail.path_before
                            )
            if context.window_manager.motion_trail.path_after == 0:
                frame_max = context.scene.frame_end
            else:
                frame_max = min(
                            context.scene.frame_end,
                            context.scene.frame_current +
                            context.window_manager.motion_trail.path_after
                            )

            for objectname, values in self.click.items():
                if found:
                    break
                for frame, type, coord, action_ob, child in values:
                    if frame < frame_min or frame > frame_max:
                        continue
                    if (coord - clicked).length <= treshold:
                        found = True
                        if type == "keyframe":
                            self.active_keyframe = [objectname, frame, frame,
                                action_ob, child]
                        elif type == "handle_left":
                            self.active_handle = [objectname, frame, "left",
                                action_ob, child]
                        elif type == "handle_right":
                            self.active_handle = [objectname, frame, "right",
                                action_ob, child]
                        elif type == "timebead":
                            self.active_timebead = [objectname, frame, frame,
                                action_ob, child]
                        elif type == "frame":
                            self.active_frame = [objectname, frame, frame,
                                action_ob, child]
                        break
            if not found:
                context.window_manager.motion_trail.handle_type_enabled = False
                # no motion trail selections, so pass on to normal select()
                if bpy.ops.view3d.select.poll():
                    bpy.ops.view3d.select('INVOKE_DEFAULT')
            else:
                handle_type = get_handle_type(self.active_keyframe,
                    self.active_handle)
                if handle_type:
                    context.window_manager.motion_trail.handle_type_old = \
                        handle_type
                    context.window_manager.motion_trail.handle_type = \
                        handle_type
                else:
                    context.window_manager.motion_trail.handle_type_enabled = \
                        False
        elif event.type == 'LEFTMOUSE' and event.value == 'PRESS' and \
        self.drag:
            # stop drag
            self.drag = False
            self.lock = True
            context.window_manager.motion_trail.force_update = True
        elif event.type == 'LEFTMOUSE' and event.value == 'PRESS' and not\
        event.alt and not event.ctrl and not event.shift:
            if eval("bpy.ops." + self.left_action + ".poll()"):
                eval("bpy.ops." + self.left_action + "('INVOKE_DEFAULT')")

        if context.area:  # not available if other window-type is fullscreen
            context.area.tag_redraw()

        return {'PASS_THROUGH'}

    def invoke(self, context, event):
        if context.area.type != 'VIEW_3D':
            self.report({'WARNING'}, "View3D not found, cannot run operator")
            return {'CANCELLED'}

        # get clashing keymap items
        wm = context.window_manager
        keyconfig = wm.keyconfigs.active
        select = getattr(keyconfig.preferences, "select_mouse", "LEFT")
        kms = [
            bpy.context.window_manager.keyconfigs.active.keymaps['3D View'],
            bpy.context.window_manager.keyconfigs.active.keymaps['Object Mode']
            ]
        kmis = []
        self.left_action = None
        self.right_action = None
        for km in kms:
            for kmi in km.keymap_items:
                if kmi.idname == "transform.translate" and \
                kmi.map_type == 'KEYBOARD' and not \
                kmi.properties.texture_space:
                    kmis.append(kmi)
                    self.transform_key = kmi.type
                elif (kmi.type == 'ACTIONMOUSE' and select == 'RIGHT') \
                and not kmi.alt and not kmi.any and not kmi.ctrl \
                and not kmi.shift:
                    kmis.append(kmi)
                    self.left_action = kmi.idname
                elif kmi.type == 'SELECTMOUSE' and not kmi.alt and not \
                kmi.any and not kmi.ctrl and not kmi.shift:
                    kmis.append(kmi)
                    if select == 'RIGHT':
                        self.right_action = kmi.idname
                    else:
                        self.left_action = kmi.idname
                elif kmi.type == 'LEFTMOUSE' and not kmi.alt and not \
                kmi.any and not kmi.ctrl and not kmi.shift:
                    kmis.append(kmi)
                    self.left_action = kmi.idname

        if not context.window_manager.motion_trail.enabled:
            # enable
            self.active_keyframe = False
            self.active_handle = False
            self.active_timebead = False
            self.active_frame = False
            self.click = {}
            self.drag = False
            self.lock = True
            self.perspective = context.region_data.perspective_matrix
            self.displayed = []
            context.window_manager.motion_trail.force_update = True
            context.window_manager.motion_trail.handle_type_enabled = False
            self.cached = {
                    "path": {}, "keyframes": {},
                    "timebeads_timing": {}, "timebeads_speed": {}
                    }

            for kmi in kmis:
                kmi.active = False

            MotionTrailOperator.handle_add(self, context)
            context.window_manager.motion_trail.enabled = True

            if context.area:
                context.area.tag_redraw()

            context.window_manager.modal_handler_add(self)
            return {'RUNNING_MODAL'}

        else:
            # disable
            for kmi in kmis:
                kmi.active = True
            MotionTrailOperator.handle_remove()
            context.window_manager.motion_trail.enabled = False

            if context.area:
                context.area.tag_redraw()

            return {'FINISHED'}


class MotionTrailPanel(bpy.types.Panel):
    bl_idname = "VIEW3D_PT_motion_trail"
    bl_category = "Animation"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_label = "Motion Trail"
    bl_options = {'DEFAULT_CLOSED'}

    @classmethod
    def poll(cls, context):
        if context.active_object is None:
            return False
        return context.active_object.mode in ('OBJECT', 'POSE')

    def draw(self, context):
        col = self.layout.column()
        if not context.window_manager.motion_trail.enabled:
            col.operator("view3d.motion_trail", text="Enable motion trail")
        else:
            col.operator("view3d.motion_trail", text="Disable motion trail")

        box = self.layout.box()
        box.prop(context.window_manager.motion_trail, "mode")
        # box.prop(context.window_manager.motion_trail, "calculate")
        if context.window_manager.motion_trail.mode == 'timing':
            box.prop(context.window_manager.motion_trail, "timebeads")

        box = self.layout.box()
        col = box.column()
        row = col.row()

        if context.window_manager.motion_trail.path_display:
            row.prop(context.window_manager.motion_trail, "path_display",
                icon="DOWNARROW_HLT", text="", emboss=False)
        else:
            row.prop(context.window_manager.motion_trail, "path_display",
                icon="RIGHTARROW", text="", emboss=False)

        row.label(text="Path options")

        if context.window_manager.motion_trail.path_display:
            col.prop(context.window_manager.motion_trail, "path_style",
                text="Style")
            grouped = col.column(align=True)
            grouped.prop(context.window_manager.motion_trail, "path_width",
                text="Width")
            grouped.prop(context.window_manager.motion_trail,
                "path_transparency", text="Transparency")
            grouped.prop(context.window_manager.motion_trail,
                "path_resolution")
            row = grouped.row(align=True)
            row.prop(context.window_manager.motion_trail, "path_before")
            row.prop(context.window_manager.motion_trail, "path_after")
            col = col.column(align=True)
            col.prop(context.window_manager.motion_trail, "keyframe_numbers")
            col.prop(context.window_manager.motion_trail, "frame_display")

        if context.window_manager.motion_trail.mode == 'location':
            box = self.layout.box()
            col = box.column(align=True)
            col.prop(context.window_manager.motion_trail, "handle_display",
                text="Handles")
            if context.window_manager.motion_trail.handle_display:
                row = col.row()
                row.enabled = context.window_manager.motion_trail.\
                    handle_type_enabled
                row.prop(context.window_manager.motion_trail, "handle_type")


class MotionTrailProps(bpy.types.PropertyGroup):
    def internal_update(self, context):
        context.window_manager.motion_trail.force_update = True
        if context.area:
            context.area.tag_redraw()

    # internal use
    enabled: BoolProperty(default=False)

    force_update: BoolProperty(name="internal use",
        description="Force calc_callback to fully execute",
        default=False)

    handle_type_enabled: BoolProperty(default=False)
    handle_type_frame: FloatProperty()
    handle_type_side: StringProperty()
    handle_type_action_ob: StringProperty()
    handle_type_child: StringProperty()

    handle_type_old: EnumProperty(
            items=(
                ("AUTO", "", ""),
                ("AUTO_CLAMPED", "", ""),
                ("VECTOR", "", ""),
                ("ALIGNED", "", ""),
                ("FREE", "", "")),
            default='AUTO'
            )
    # visible in user interface
    calculate: EnumProperty(name="Calculate", items=(
            ("fast", "Fast", "Recommended setting, change if the "
                             "motion path is positioned incorrectly"),
            ("full", "Full", "Takes parenting and modifiers into account, "
                             "but can be very slow on complicated scenes")),
            description="Calculation method for determining locations",
            default='full',
            update=internal_update
            )
    frame_display: BoolProperty(name="Frames",
            description="Display frames, \n test",
            default=True,
            update=internal_update
            )
    handle_display: BoolProperty(name="Display",
            description="Display handles",
            default=True,
            update=internal_update
            )
    handle_type: EnumProperty(name="Type", items=(
            ("AUTO", "Automatic", ""),
            ("AUTO_CLAMPED", "Auto Clamped", ""),
            ("VECTOR", "Vector", ""),
            ("ALIGNED", "Aligned", ""),
            ("FREE", "Free", "")),
            description="Set handle type for the selected handle",
            default='AUTO',
            update=set_handle_type
            )
    keyframe_numbers: BoolProperty(name="Keyframe numbers",
            description="Display keyframe numbers",
            default=False,
            update=internal_update
            )
    mode: EnumProperty(name="Mode", items=(
            ("location", "Location", "Change path that is followed"),
            ("speed", "Speed", "Change speed between keyframes"),
            ("timing", "Timing", "Change position of keyframes on timeline")),
            description="Enable editing of certain properties in the 3d-view",
            default='location',
            update=internal_update
            )
    path_after: IntProperty(name="After",
            description="Number of frames to show after the current frame, "
                        "0 = display all",
            default=50,
            min=0,
            update=internal_update
            )
    path_before: IntProperty(name="Before",
            description="Number of frames to show before the current frame, "
                        "0 = display all",
            default=50,
            min=0,
            update=internal_update
            )
    path_display: BoolProperty(name="Path options",
            description="Display path options",
            default=True
            )
    path_resolution: IntProperty(name="Resolution",
            description="10 is smoothest, but could be "
                        "slow when adjusting keyframes, handles or timebeads",
            default=10,
            min=1,
            max=10,
            update=internal_update
            )
    path_style: EnumProperty(name="Path style", items=(
            ("acceleration", "Acceleration", "Gradient based on relative acceleration"),
            ("simple", "Simple", "Black line"),
            ("speed", "Speed", "Gradient based on relative speed")),
            description="Information conveyed by path color",
            default='simple',
            update=internal_update
            )
    path_transparency: IntProperty(name="Path transparency",
            description="Determines visibility of path",
            default=0,
            min=0,
            max=100,
            subtype='PERCENTAGE',
            update=internal_update
            )
    path_width: IntProperty(name="Path width",
            description="Width in pixels",
            default=1,
            min=1,
            soft_max=5,
            update=internal_update
            )
    timebeads: IntProperty(name="Time beads",
            description="Number of time beads to display per segment",
            default=5,
            min=1,
            soft_max=10,
            update=internal_update
            )


classes = (
        MotionTrailProps,
        MotionTrailOperator,
        MotionTrailPanel,
        )


def register():
    for cls in classes:
        bpy.utils.register_class(cls)

    bpy.types.WindowManager.motion_trail = PointerProperty(
                                                type=MotionTrailProps
                                                )


def unregister():
    MotionTrailOperator.handle_remove()
    for cls in classes:
        bpy.utils.unregister_class(cls)

    del bpy.types.WindowManager.motion_trail


if __name__ == "__main__":
    register()