auto save

my_tree.py

 import turtle  # 导入turtle模块
+import random  # 导入random模块
 
 pen = turtle.Turtle()  # 创建画笔
 pen.color('sienna')    # 设置画笔颜色
+pen.speed(0)
 # 画布大小
 w = turtle.Screen()    
 w.bgcolor('wheat')     # 设置画布颜色wheat小麦
@@ -11,18 +13,30 @@ pen.up()             # 抬笔
 pen.backward(150)    # 后退150
 pen.down()           # 落笔
 
-# 分形树
+# 樱花树
 def tree(n)    :   # def定义tree()函数参数为n
-    if n >= 50:     # if判段变量n>=50
+    if n >= 0:     # if判段变量n>=0
+        if n <= 12:  # if判断变量n<=12
+            # 建立列表color_list，索引0为'snow'索引1为'lightcoral'
+            color_list = ['snow', 'lightcoral']
+            # 用random.choice()方法参数为color_list并赋值给变量color_list
+            color = random.choice(color_list)
+            pen.color(color)      # 用pen.color()方法参数为color
+            pen.pensize(n / 3)    # 用pen.pensize()方法参数为n / 3
+        else:  # 否则
+            pen.color('sienna')  # 赭（zhe）色
+            pen.pensize(n / 10)  # 用pen.pensize()方法参数为n / 10
         pen.forward(n)  # 前进变量n
-        pen.right(30)  # 右转30
-        tree(n-10)         # 函数tree()的值设为n-50
-        pen.left(60)   # 左转60
-        tree(n-10)         # 函数tree()的值设为n-50
-        pen.right(30)  # 右转30
+        angle = random.random() # 用random.random()方法并赋值给变量angle
+        pen.right(30*angle)  # 右转30乘angle
+        length = 1.5*random.random() # 用random.random()方法*1.5 并赋值给变量length
+        tree(n-10*length)         # 函数tree()的值设为n-10*length
+        pen.left(60*angle)   # 左转60*angle
+        tree(n-10*length)         # 函数tree()的值设为n-10*length
+        pen.right(30*angle)  # 右转30*angle
         pen.up()       # 抬笔
-        pen.backward(n)           # 用backward()方法n
-        pen.down()           # 用down()方法落笔
+        pen.backward(n)     # 用backward()方法后退变量n
+        pen.down()           # 落笔
 
-tree(100)  # tree()方法参数设为100
-turtle.done()
+tree(60)  # tree()方法参数设为60
+turtle.done()  # 停止画笔绘画