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# examples derived from
# Visual Modeling with Logo: A Structural Approach to Seeing
# by James Clayson
from wrappers import Turtle
import math
from math import pi, sin
class GonTurtle(Turtle):
# same as polygon, but without the efficiency ;-)
def ngon(self, n, edge):
for i in range(n):
self.fd(edge)
self.rt(360.0 / n)
# draw a n-sided polygon with radius rad
# p. 30
def cngon(self, n, rad):
self.pu()
self.fd(rad)
angle = 180 - (90 * (n - 2) / n)
self.rt(angle)
self.pd()
edge = 2 * rad * sin(pi / n) # logo uses sin(180 / n); Python uses radians
self.ngon(n, edge)
self.left(angle)
self.pu()
self.bk(rad)
self.pd()
# p. 22
def spingon(self, n, edge, angle, growth, times):
if times < 1:
return
self.ngon(n, edge)
self.rt(angle)
self.spingon(n, edge * growth, angle, growth, times - 1)
# another way to do recursion, though the way above seems best
"""
def spingon(self, n, edge, angle, growth, times):
if times > 0:
self.ngon(n, edge)
self.rt(angle)
self.spingon(n, edge * growth, angle, growth, times - 1)
"""
def draw(canvas):
t = GonTurtle(canvas)
t.cls()
# check that variations of plot works
"""
t.plot() # uses current x, y #t.plot(375, 300)
t.plot(None,10)
t.plot(10,None)
"""
# p. 21
#t.spingon(50, 3, 10, 1.02, 95)
radius = 150
# check the radius by uncommenting this
"""
t.color('blue')
for i in range(36):
t.fd(radius)
t.bk(radius)
t.rt(10)
"""
"""
# show that as the number of sides increases
# the distance traveled approaches the circumference
# of the circle
# use the built-in cPolygon (centered-Polygon aTurtle class method)
# output is sent to the console window
print "circumference: %f" % (2 * pi * radius)
for i in range(3, 30):
t.resetOdometer()
t.resumeOdometer()
t.cPolygon(i, radius)
dist = t.getOdometer() - (2 * radius)
print "sides: %d, distance: %f" % (i, dist)
t.suspendOdometer()
"""
# same as t.color('black')
t.color(0, 0, 0)
# any r, g, b values between 0 - 255 are valid
t.color(50, 100, 200)
""""""
for i in range(10):
t.cngon(8, radius)
#t.cngon(6, radius)
#t.cngon(5, radius)
#t.cngon(4, radius)
#t.cngon(3, radius)
t.rt(5)
radius = radius - 5
""""""
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