# Recursively draw the Mandelbrot set
# Dependencies: Python 2.7.5, PyGame 1.9.1
import pygame
from pygame.locals import QUIT
from sys import exit
# size must be a power of 2 or you will get rounding errors in the image
# E.g. 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, ...
size = 512
pygame.init()
surface = pygame.display.set_mode((size, size), 0, 32)
# Mandelbrot drawing area
xa = -2.0
xb = 1.0
ya = -1.5
yb = 1.5
# maximum iterations
maxIt = 256
def pump():
# pump the event queue so the window is responsive, exit if signaled
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
exit()
def point(x, y):
# get the escape value of a specific coordinate in the Mandelbrot set
zy = y * (yb - ya) / size + ya
zx = x * (xb - xa) / size + xa
z = zx + zy * 1j
c = z
for i in range(maxIt):
if abs(z) > 2.0: break
z = z * z + c
return i
def col(i):
# return a color variable computed from a escape value
return (i % 4 * 64, i % 8 * 32, i % 16 * 16)
def mandel(x, y, i_size):
p1 = point(x, y)
# test if the square needs to be further sub-divided
# test every pixel around the square, if they are all the same color fill
test = False
for i in range(i_size):
t1 = point(x, y + i)
t2 = point(x + i, y)
t3 = point(x + i_size, y + i)
t4 = point(x + i, y + i_size)
if (p1 != t1 or p1 != t2 or p1 !=t3 or p1 != t4):
test = True
break
if test:
# plot corner points and sub-divide area
p2 = point(x + i_size, y)
p3 = point(x + i_size, y + i_size)
p4 = point(x, y + i_size)
surface.lock()
surface.set_at((x, y), col(p1))
surface.set_at((x + i_size, y), col(p2))
surface.set_at((x + i_size, y + i_size), col(p3))
surface.set_at((x, y + i_size), col(p4))
surface.unlock()
# base case, dividing by 2: when 1 / 2 = 0.5 is floored to 0
half = i_size / 2
if half != 0:
mandel(x, y, half)
mandel(x + half, y, half)
mandel(x + half, y + half, half)
mandel(x, y + half, half)
else:
return
else:
# all square border points are same color, fill area
surface.fill(col(p1), (x, y, i_size, i_size))
pygame.display.update()
pump()
# calculate the image
mandel(0, 0, size)
# Wait for user to click close widget on window
while True:
pump()
Diff to Previous Revision
--- revision 4 2013-08-10 06:14:53
+++ revision 5 2013-08-10 06:16:55
@@ -61,8 +61,6 @@
if test:
# plot corner points and sub-divide area
- half = i_size / 2
-
p2 = point(x + i_size, y)
p3 = point(x + i_size, y + i_size)
p4 = point(x, y + i_size)
@@ -75,6 +73,7 @@
surface.unlock()
# base case, dividing by 2: when 1 / 2 = 0.5 is floored to 0
+ half = i_size / 2
if half != 0:
mandel(x, y, half)
mandel(x + half, y, half)