'''
FIREWORKS SIMULATION WITH TKINTER
*self-containing code
*to run: simply type python simple.py in your console
*compatible with both Python 2 and Python 3
*Dependencies: tkinter, Pillow (only for background image)
*The design is based on high school physics, with some small twists only for aesthetics purpose
 
import tkinter as tk
#from tkinter import messagebox
#from tkinter import PhotoImage
from PIL import Image, ImageTk
from time import time, sleep
from random import choice, uniform, randint
from math import sin, cos, radians
# gravity, act as our constant g, you can experiment by changing it
GRAVITY = 0.05
# list of color, can choose randomly or use as a queue (FIFO)
colors = ['red', 'blue', 'yellow', 'white', 'green', 'orange', 'purple', 'seagreen','indigo', 'cornflowerblue']
Generic class for particles
particles are emitted almost randomly on the sky, forming a round of circle (a star) before falling and getting removed
from canvas
Attributes:
  - id: identifier of a particular particle in a star
  - x, y: x,y-coordinate of a star (point of explosion)
  - vx, vy: speed of particle in x, y coordinate
  - total: total number of particle in a star
  - age: how long has the particle last on canvas
  - color: self-explantory
  - cv: canvas
  - lifespan: how long a particle will last on canvas
class part:
  def __init__(self, cv, idx, total, explosion_speed, x=0., y=0., vx = 0., vy = 0., size=2., color = 'red', lifespan = 2, **kwargs):
    self.id = idx
    self.x = x
    self.y = y
    self.initial_speed = explosion_speed
    self.vx = vx
    self.vy = vy
    self.total = total
    self.age = 0
    self.color = color
    self.cv = cv
    self.cid = self.cv.create_oval(
      x - size, y - size, x + size,
      y + size, fill=self.color)
    self.lifespan = lifespan
  def update(self, dt):
    self.age += dt
    # particle expansions
    if self.alive() and self.expand():
      move_x = cos(radians(self.id*360/self.total))*self.initial_speed
      move_y = sin(radians(self.id*360/self.total))*self.initial_speed
      self.cv.move(self.cid, move_x, move_y)
      self.vx = move_x/(float(dt)*1000)
    # falling down in projectile motion
    elif self.alive():
      move_x = cos(radians(self.id*360/self.total))
      # we technically don't need to update x, y because move will do the job
      self.cv.move(self.cid, self.vx + move_x, self.vy+GRAVITY*dt)
      self.vy += GRAVITY*dt
    # remove article if it is over the lifespan
    elif self.cid is not None:
      cv.delete(self.cid)
      self.cid = None
  # define time frame for expansion
  def expand (self):
    return self.age <= 1.2
  # check if particle is still alive in lifespan
  def alive(self):
    return self.age <= self.lifespan
Firework simulation loop:
Recursively call to repeatedly emit new fireworks on canvas
a list of list (list of stars, each of which is a list of particles)
is created and drawn on canvas at every call, 
via update protocol inside each 'part' object 
def simulate(cv):
  t = time()
  explode_points = []
  wait_time = randint(10,100)
  numb_explode = randint(6,10)
  # create list of list of all particles in all simultaneous explosion
  for point in range(numb_explode):
    objects = []
    x_cordi = randint(50,550)
    y_cordi = randint(50, 150)
    speed = uniform (0.5, 1.5)     
    size = uniform (0.5,3)
    color = choice(colors)
    explosion_speed = uniform(0.2, 1)
    total_particles = randint(10,50)
    for i in range(1,total_particles):
      r = part(cv, idx = i, total = total_particles, explosion_speed = explosion_speed, x = x_cordi, y = y_cordi, 
        vx = speed, vy = speed, color=color, size = size, lifespan = uniform(0.6,1.75))
      objects.append(r)
    explode_points.append(objects)
  total_time = .0
  # keeps undate within a timeframe of 1.8 second
  while total_time < 1.8:
    sleep(0.01)
    tnew = time()
    t, dt = tnew, tnew - t
    for point in explode_points:
      for item in point:
        item.update(dt)
    cv.update()
    total_time += dt
  # recursive call to continue adding new explosion on canvas
  root.after(wait_time, simulate, cv)
def close(*ignore):
  """Stops simulation loop and closes the window."""
  global root
  root.quit()
  
if __name__ == '__main__':
  root = tk.Tk()
  cv = tk.Canvas(root, height=600, width=600)
  # use a nice background image
  image = Image.open("./image1.jpg")#背景照片路径自行选择，可以选择酷炫一点的，看起来效果会#更好
  photo = ImageTk.PhotoImage(image)
  cv.create_image(0, 0, image=photo, anchor='nw')
  cv.pack()
  root.protocol("WM_DELETE_WINDOW", close)
  root.after(100, simulate, cv)
  root.mainloop()