def generate_target_line(self, n_samples=100):
        """
        Using object trajectory (self.poses), build a line to compare to for frechet distance.
        Updates this attribute on object.
        :param n_samples: number of samples for target line. Defaults to 100
        """
        x_vals, y_vals = aplt.get_direction(self.trial_translation, n_samples)

        target_line = np.column_stack((x_vals, y_vals))

        # get last object pose and use it for determining how far target line should go
        last_obj_pose = self.poses.tail(1).to_numpy()[0]

        target_line_length = acalc.narrow_target(last_obj_pose, target_line)

        if target_line_length:
            distance_travelled = acalc.t_distance(
                [0, 0], target_line[target_line_length + 1])
            final_target_ln = target_line[:target_line_length]
        else:
            distance_travelled = acalc.t_distance([0, 0], target_line[0])
            final_target_ln = target_line[:1]

        # TODO: distance travelled has error because it is built of target line... maybe use last_obj_pose instead?
        return final_target_ln, distance_travelled
    def plot_direction(self,
                       translation,
                       rotation="n",
                       show_plot=True,
                       save_plot=False):
        """
        Plot the average path for each hand data object contained in this object for a specific
        translation rotation pair.
        """
        colors = [
            "tab:blue", "tab:purple", "tab:red", "tab:olive", "tab:cyan",
            "tab:green", "tab:pink", "tab:orange"
        ]

        # grab the average values from all hands
        avg_label = f"{translation}_{rotation}"
        averages_to_plot = []
        hand_order = []

        for h in self.hands:
            hand_order.append(h.hand.get_name())

            for a in h.averages:
                a_label = f"{a.trial_translation}_{a.trial_rotation}"

                if a_label == avg_label:
                    averages_to_plot.append(a)

        for i, a in enumerate(averages_to_plot):
            a_x, a_y, _ = a.get_poses()

            plt.plot(a_x, a_y, color=colors[i], label=hand_order[i])

        # plot the straight line
        t_x, t_y = AsteriskPlotting.get_direction(translation)
        plt.plot(t_x, t_y, color="r", linestyle="dashed")

        if save_plot:
            # added the zero to guarantee that it comes first
            plt.savefig(f"pics/0all_{rotation}.jpg", format='jpg')
            # name -> tuple: subj, hand  names
            print("Figure saved.")
            print(" ")

        if show_plot:
            plt.legend()
            plt.show()

        return plt