本节书摘来自异步社区《Python极客项目编程 》一书中的第2章，第2.4节，作者 [美] Mahesh Venkitachalam，王海鹏 译，更多章节内容可以访问云栖社区“异步社区”公众号查看。

2.4　完整代码

下面是完整的万花尺程序。也可以从https://github.com/electronut/pp/blob/master/ spirograph/spiro.py 下载该项目的代码。

import sys, random, argparse
import numpy as np
import math
import turtle
import random
from PIL import Image
from datetime import datetime
from fractions import gcd# a class that draws a Spirograph
class Spiro:# constructordef __init__(self, xc, yc, col, R, r, l):# create the turtle objectself.t = turtle.Turtle()# set the cursor shapeself.t.shape('turtle')# set the step in degreesself.step = 5# set the drawing complete flagself.drawingComplete = False# set the parametersself.setparams(xc, yc, col, R, r, l)# initialize the drawingself.restart()# set the parametersdef setparams(self, xc, yc, col, R, r, l):# the Spirograph parametersself.xc = xcself.yc = ycself.R = int(R)self.r = int(r)self.l = lself.col = col# reduce r/R to its smallest form by dividing with the GCDgcdVal = gcd(self.r, self.R)self.nRot = self.r//gcdVal# get ratio of radiiself.k = r/float(R)# set the colorself.t.color(*col)# store the current angleself.a = 0# restart the drawingdef restart(self):# set the flagself.drawingComplete = False# show the turtleself.t.showturtle()# go to the first pointself.t.up()R, k, l = self.R, self.k, self.la = 0.0x = R*((1-k)*math.cos(a) + l*k*math.cos((1-k)*a/k))y = R*((1-k)*math.sin(a) - l*k*math.sin((1-k)*a/k))self.t.setpos(self.xc + x, self.yc + y)self.t.down()# draw the whole thingdef draw(self):# draw the rest of the pointsR, k, l = self.R, self.k, self.lfor i in range(0, 360*self.nRot + 1, self.step):a = math.radians(i)x = R*((1-k)*math.cos(a) + l*k*math.cos((1-k)*a/k))y = R*((1-k)*math.sin(a) - l*k*math.sin((1-k)*a/k))self.t.setpos(self.xc + x, self.yc + y)# drawing is now done so hide the turtle cursorself.t.hideturtle()# update by one stepdef update(self):# skip the rest of the steps if doneif self.drawingComplete:return# increment the angleself.a += self.step# draw a stepR, k, l = self.R, self.k, self.l# set the anglea = math.radians(self.a)x = self.R*((1-k)*math.cos(a) + l*k*math.cos((1-k)*a/k))y = self.R*((1-k)*math.sin(a) - l*k*math.sin((1-k)*a/k))self.t.setpos(self.xc + x, self.yc + y)# if drawing is complete, set the flagif self.a >= 360*self.nRot:self.drawingComplete = True# drawing is now done so hide the turtle cursorself.t.hideturtle()# clear everythingdef clear(self):self.t.clear()# a class for animating Spirographs
class SpiroAnimator:# constructordef __init__(self, N):# set the timer value in millisecondsself.deltaT = 10# get the window dimensionsself.width = turtle.window_width()self.height = turtle.window_height()# create the Spiro objectsself.spiros = []for i in range(N):# generate random parametersrparams = self.genRandomParams()# set the spiro parametersspiro = Spiro(*rparams)self.spiros.append(spiro)# call timerturtle.ontimer(self.update, self.deltaT)# restart spiro drawingdef restart(self):for spiro in self.spiros:# clearspiro.clear()# generate random parametersrparams = self.genRandomParams()# set the spiro parametersspiro.setparams(*rparams)# restart drawingspiro.restart()# generate random parametersdef genRandomParams(self):width, height = self.width, self.heightR = random.randint(50, min(width, height)//2)r = random.randint(10, 9*R//10)l = random.uniform(0.1, 0.9)xc = random.randint(-width//2, width//2)yc = random.randint(-height//2, height//2)col = (random.random(),random.random(),random.random())return (xc, yc, col, R, r, l)def update(self):# update all spirosnComplete = 0for spiro in self.spiros:# updatespiro.update()# count completed spirosif spiro.drawingComplete:nComplete += 1# restart if all spiros are completeif nComplete == len(self.spiros):self.restart()# call the timerturtle.ontimer(self.update, self.deltaT)# toggle turtle cursor on and offdef toggleTurtles(self):for spiro in self.spiros:if spiro.t.isvisible():spiro.t.hideturtle()else:spiro.t.showturtle()# save drawings as PNG files
def saveDrawing():# hide the turtle cursorturtle.hideturtle()# generate unique filenamesdateStr = (datetime.now()).strftime("%d%b%Y-%H%M%S")fileName = 'spiro-' + dateStrprint('saving drawing to %s.eps/png' % fileName)# get the tkinter canvascanvas = turtle.getcanvas()# save the drawing as a postscipt imagecanvas.postscript(file = fileName + '.eps')# use the Pillow module to convert the poscript image file to PNGimg = Image.open(fileName + '.eps')img.save(fileName + '.png', 'png')# show the turtle cursorturtle.showturtle()# main() function
def main():# use sys.argv if neededprint('generating spirograph...')# create parserdescStr = """This program draws Spirographs using the Turtle module.When run with no arguments, this program draws random Spirographs.Terminology:R: radius of outer circler: radius of inner circlel: ratio of hole distance to r"""parser = argparse.ArgumentParser(description=descStr)# add expected argumentsparser.add_argument('--sparams', nargs=3, dest='sparams', required=False,help="The three arguments in sparams: R, r, l.")# parse argsargs = parser.parse_args()# set the width of the drawing window to 80 percent of the screen widthturtle.setup(width=0.8)# set the cursor shape to turtleturtle.shape('turtle')# set the title to Spirographs!turtle.title("Spirographs!")# add the key handler to save our drawingsturtle.onkey(saveDrawing, "s")# start listeningturtle.listen()# hide the main turtle cursorturtle.hideturtle()# check for any arguments sent to --sparams and draw the Spirographif args.sparams:params = [float(x) for x in args.sparams]# draw the Spirograph with the given parameterscol = (0.0, 0.0, 0.0)spiro = Spiro(0, 0, col, *params)spiro.draw()else:# create the animator objectspiroAnim = SpiroAnimator(4)# add a key handler to toggle the turtle cursorturtle.onkey(spiroAnim.toggleTurtles, "t")# add a key handler to restart the animationturtle.onkey(spiroAnim.restart, "space")# start the turtle main loopturtle.mainloop()# call main
if __name__ == '__main__':main()