Separate state generation from UI.

Now the UI loads instantaneously (the starfield takes noticable time to
generate with the Poisson process.)

data.py

@@ -0,0 +1,13 @@
+'''
+I could use SQLite for a data file format, or just pickle.
+'''
+
+from pickle import load as pload, dump
+
+def save(fn, game_state):
+    with open(fn, 'wb') as f:
+        dump(game_state, f, protocol=0)
+
+def load(fn):
+    with open(fn, 'rb') as f:
+        return pload(f)

server.py

@@ -0,0 +1,23 @@
+from random import randint, expovariate, seed
+from data import save
+from poisson import poisson
+
+
+MINIMUM_DISTANCE_BETWEEN_STARS = 160
+WIDTH, HEIGHT = 10240, 7680
+
+
+seed(23)
+
+print('Generating data.')
+state = dict(
+    width = WIDTH,
+    height = HEIGHT,
+    stars = {
+        (x, y): round(1 + expovariate(1))
+        for x, y in poisson(WIDTH, HEIGHT, MINIMUM_DISTANCE_BETWEEN_STARS)
+        },
+    )
+
+print('Saving game.state')
+save('game.state', state)

ui.py

@@ -3,7 +3,7 @@ from tkinter import *
 from PIL import Image
 from PIL.ImageTk import PhotoImage
 
-from poisson import poisson
+from data import load
 
 
 class App:
@@ -44,21 +44,14 @@ class App:
 
 
 
-from random import randint, expovariate, seed
+state = load('game.state')
+width, height = state['width'], state['height']
 
-seed(23)
-
-width, height = 10240, 7680
 root = Tk()
 app = App(root, bg='black', scrollregion=(0, 0, width, height))
 app.frame.pack(expand=True, fill=BOTH)
 
-k = poisson(width, height, 160)
-
-for x, y in k:
-    #x, y = randint(0, width - 1), randint(0, height - 1)
-    #radius = randint(2, 10) // 2
-    radius = round(1 + expovariate(1))
+for (x, y), radius in state['stars'].items():
     app.canvas.create_oval(
         x - radius, y - radius,
         x + radius, y + radius,