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下列turtle库的简单常用指令
?forward(distance) #将箭头移到某一指定坐标
?left(angel) right(angel)
?penup() #提起笔,用于另起一个地方绘制时用,与pendown()配对使用
?goto(x,y)
?home()
?circle(radius)
?speed()
1 #五角星图形 2 from turtle import Turtle 3 4 p = Turtle() 5 p.speed(3) 6 p.pensize(5) 7 p.color("black", ‘yellow‘) 8 #p.fillcolor("red") 9 p.begin_fill() 10 for i in range(5): 11 p.forward(200) #将箭头移到某一指定坐标 12 p.right(144) #当前方向上向右转动角度 13 p.end_fill()
树的绘制
?观察:对称树, 从主杆出发以一定角度向左向右生成对称的枝丫, 且每一棵枝杈上以相同的角度生成更小的左右枝杈,如此往复。
联系:所学内容,易想到利用递归程序实现;
1 # drawtree.py 2 3 from turtle import Turtle, mainloop 4 5 def tree(plist, l, a, f): 6 """ plist is list of pens 7 l is length of branch 8 a is half of the angle between 2 branches 9 f is factor by which branch is shortened 10 from level to level.""" 11 if l > 5: # 12 lst = [] 13 for p in plist: 14 p.forward(l)#沿着当前的方向画画Move the turtle forward by the specified distance, in the direction the turtle is headed. 15 q = p.clone()#Create and return a clone of the turtle with same position, heading and turtle properties. 16 p.left(a) #Turn turtle left by angle units 17 q.right(a)#Turn turtle right by angle units, nits are by default degrees, but can be set via the degrees() and radians() functions. 18 lst.append(p)#将元素增加到列表的最后 19 lst.append(q) 20 tree(lst, l*f, a, f) 21 22 23 24 def main(): 25 p = Turtle() 26 p.color("green") 27 p.pensize(5) 28 #p.setundobuffer(None) 29 p.hideturtle() #Make the turtle invisible. It’s a good idea to do this while you’re in the middle of doing some complex drawing, 30 #because hiding the turtle speeds up the drawing observably. 31 32 p.getscreen().tracer(10,0) 33 #Return the TurtleScreen object the turtle is drawing on. 34 #TurtleScreen methods can then be called for that object. 35 #p.speed(10) 36 p.left(90) #Turn turtle left by angle units. direction 调整画笔 37 38 p.penup() #Pull the pen up – no drawing when moving. 39 p.goto(0,-200)#Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation. 40 p.pendown()# Pull the pen down – drawing when moving. 这三条语句是一个组合相当于先把笔收起来再移动到指定位置,再把笔放下开始画 41 #否则turtle一移动就会自动的把线画出来 42 43 #t = tree([p], 200, 65, 0.6375) 44 t = tree([p], 200, 65, 0.6375) 45 46 main()
森林的绘制
?如何画出多棵树,甚至整片森林呢?
?答案很简单,只要在画每棵树之前调整画笔的位置,调用画树程序,就可以从新位置生成一颗新树了。
?利用模块化的函数思想,调整代码:
?将每棵树的绘制以maketree函数封装,参数x,y为画树的起点位置即树根位置。在main函数中只要以
不同的参数设置来调用maketree函数就可以完成多棵树的绘制了
1 # drawtree.py 2 from turtle import Turtle, mainloop 3 4 def tree(plist, l, a, f): 5 """ plist is list of pens 6 l is length of branch 7 a is half of the angle between 2 branches 8 f is factor by which branch is shortened 9 from level to level.""" 10 if l > 5: # 11 lst = [] 12 for p in plist: 13 p.forward(l)#沿着当前的方向画画Move the turtle forward by the specified distance, in the direction the turtle is headed. 14 q = p.clone()#Create and return a clone of the turtle with same position, heading and turtle properties. 15 p.left(a) #Turn turtle left by angle units 16 q.right(a)#Turn turtle right by angle units, nits are by default degrees, but can be set via the degrees() and radians() functions. 17 lst.append(p)#将元素增加到列表的最后 18 lst.append(q) 19 tree(lst, l*f, a, f) 20 21 def maketree(x, y): 22 p = Turtle() 23 p.color("green") 24 p.pensize(5) 25 p.hideturtle() 26 p.getscreen().tracer(30, 0) 27 p.left(90) 28 29 p.penup() 30 p.goto(x, y) 31 p.pendown() 32 33 t = tree([p], 110, 65, 0.6375) 34 print(len(p.getscreen().turtles())) #用了多少个turtle绘制 35 36 def main(): 37 maketree(-200, -200) 38 maketree(0, 0) 39 maketree(200, -200) 40 41 main()
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原文地址:http://www.cnblogs.com/aze-003/p/5127843.html