blender8r

import bpy

gpencil_data = bpy.data.grease_pencils.new("GPencil")
gpencil = bpy.data.objects.new(gpencil_data.name, gpencil_data)
bpy.context.collection.objects.link(gpencil)

gp_layer = gpencil_data.layers.new("lines")

gp_frame = gp_layer.frames.new(bpy.context.scene.frame_current)

blender8r

# Generates grease pencil points with random position, size and color

import bpy
import random


sel_obj = None  
sel_objs = bpy.context.selected_objects

if sel_objs:

blender8r

# Generates grease pencil line 

import bpy
import random


def line(gp_frame, start_pos, end_pos, num_pts):
    gp_stroke = gp_frame.strokes.new()
    gp_stroke.line_width = 30
    

blender8r

# Generates grease pencil line with random noise on z axis

import bpy
import random


def line(gp_frame, start_pos, end_pos, num_pts):
    gp_stroke = gp_frame.strokes.new()
    gp_stroke.line_width = 30
    

blender8r

# Generates grease pencil line with random noise on z axis (alternate method)

import bpy
import random


def line(gp_frame, start_pos, end_pos, num_pts):
    gp_stroke = gp_frame.strokes.new()
    gp_stroke.line_width = 30
    

blender8r

# Generates grease pencil line with random noise on x and z axes

import bpy
import random
from mathutils import Vector


def line(gp_frame, start_pos, end_pos, num_pts):
    gp_stroke = gp_frame.strokes.new()
    gp_stroke.line_width = 30

blender8r

# adds a grease pencil noise modifier to the selected grease pencil object

import bpy
import random, math
from mathutils import Vector


def line(gp_frame, start_pos, end_pos, num_pts):
    gp_stroke = gp_frame.strokes.new()
    gp_stroke.line_width = 30

blender8r

import bpy
from math import pi, sin, cos


num_points = 48
center = (0.0, 0.0, 0.0)


def ellipse(gp_frame, center, radius_x, radius_z, num_points):
    gp_stroke = gp_frame.strokes.new()

blender8r

import bpy
from math import pi, sin, cos


num_points = 48
center = (0.0, 0.0, 0.0)


def ellipse(gp_frame, center, radius_x, radius_z, num_points):
    gp_stroke = gp_frame.strokes.new()

blender8r

import bpy
from math import pi, sin, cos

num_points = 10
center = (0.0, 0.0, 0.0)
    
def star(gp_frame, center, radius_x, radius_z, num_points, offset=0.75):
    gp_stroke = gp_frame.strokes.new()
    gp_stroke.line_width = 30
    gp_stroke.use_cyclic = True