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from wrappers import Turtle
def draw(canvas):
t = Turtle(canvas)
t.cls()
autoRefreshTemp = t.canvas.autoRefresh
t.canvas.autoRefresh = 0
xOffset = 50
yOffset = 0
scale = 1.0
r = 2.9
# when r was 4.0 I got an exception when doing the int
# conversion below, so I need to consider the appropriate
# behaviour when x or y is out of bounds for an int
# and also out of bounds of the current cliprect or frame
steps = 400
inc = (4.0 - 2.9) / steps
for j in range(steps):
r += inc
x = 0.3
y = j + 30
for i in range(200):
x = r * x * (1 - x)
for i in range(300):
x = r * x * (1 - x)
x1 = int(500 * x)
# originally self.plot(dc, x1, y1, xOffset, yOffset, scale)
# the scale and offset stuff should probably
# be part of the turtle or coordinate space
x2 = int(xOffset + scale * x1)
y2 = int(yOffset + scale * y)
t.plot(x2, y2)
t.canvas.refresh()
t.canvas.autoRefresh = autoRefreshTemp
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