A Concise Introduction to Programming in Python

Chapter 22

Image Synthesis

The Mandelbrot set is an interesting mathematical object that owes much

of its popularity to the computer programs that create images of it.

Listing 22.1: Mandelbrot Set

1 # mandelbrot.py

2 from image import ImagePPM

3

4 def lerp(frac, low, high):

5 return low + frac

*

(high - low)

6

7 def testpoint(c, maxreps):

8 z = 0

9 reps = 0

10 while abs(z) < 2 and reps < maxreps:

11 z = z

**

2 + c

12 reps += 1

13 frac = reps / maxreps

14 return (0, 0, int(lerp(frac, 0, 255)))

15

16 def mandelbrot(xint, yint, size, maxreps):

17 width, height = size

18 img = ImagePPM.new(size)

19 for i in range(width):

20 for j in range(height):

21 a = lerp(i / width, xint[0], ...