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# another example that doesn't actually use the turtle for drawing
import math
import sys
from wrappers import Turtle
class ChaosTurtle(Turtle):
def chaos(self, a=1.5732, xOrig=0.0, yOrig=0.0, endRange=38,
xOffset=250, yOffset=250, scale=200.0):
mult = 1.2 / endRange
tempAutoRefresh = self.canvas.autoRefresh
self.canvas.autoRefresh = False
for j in range(1, endRange + 1):
x = xOrig + mult * j
y = yOrig + mult * j
for i in range(1000):
temp = x * math.cos(a) - (y - (x * x)) * math.sin(a)
y = x * math.sin(a) + (y - (x * x)) * math.cos(a)
x = temp
try:
self.canvas.drawPoint((xOffset + scale * x, yOffset + scale * y))
except OverflowError:
pass
self.canvas.refresh()
self.canvas.autoRefresh = tempAutoRefresh
# this is an alternate implementation of the method above,
# but it uses drawPointList instead. in order to avoid
# an OverflowError exception in drawPointList an explicit
# check that x1 and y1 are in the maxint conversion range
# must be done. at least on my machine the need to create
# the temporary variables x1, y1 and the conversion check
# ends up making this method slower that the method above
def chaosWithList(self, a=1.5732, xOrig=0.0, yOrig=0.0, endRange=38,
xOffset=250, yOffset=250, scale=200.0):
mult = 1.2 / endRange
points = []
maxint = sys.maxint
for j in range(1, endRange + 1):
x = xOrig + mult * j
y = yOrig + mult * j
for i in range(1000):
temp = x * math.cos(a) - (y - (x * x)) * math.sin(a)
y = x * math.sin(a) + (y - (x * x)) * math.cos(a)
x = temp
x1 = xOffset + scale * x
y1 = yOffset + scale * y
if x1 > -maxint and x1 < maxint and y1 > -maxint and y1 < maxint:
points.append((x1, y1))
self.canvas.drawPointList(points)
def draw(canvas):
t = ChaosTurtle(canvas)
t.cls()
#t.chaos(1.5732, 0.0, 0.0, 38, 250, 250, 200)
t.chaos(1.1111, 0.0, 0.0, 38, 250, 250, 200)
# zoom in on one section of the same set as above
#t.chaos(1.1111, 0.74, 0.27, 500, 0, 0, 500)
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