萍乡李兴球的博客,萍乡少儿机器人编程/Python/C++

"""
  本程序返回折线的拐点.py
  这是研究在python turtle中实现bloodfill算法的一个副产品。
  作者:李兴球,2022/12/3号
"""
import random
import turtle

def draw_segments(points):
    turtle.penup()
    turtle.goto(points[0])
    turtle.pendown()
    [turtle.goto(dot) for dot in points[1:] ]
    turtle.penup()
    
def twopointoneline(p1,p2):
    """两点一线函数，
    p1,p2表示坐标点,用二元组表示,本函数根据两点返回一元一次方程一般式的A,B,C,k,b"""
    x1,y1 = p1
    x2,y2 = p2
    dx = x1 - x2
    if dx==0:
        k = b = float('inf')
    else:
        k = (y1-y2)/dx
        b = (x1*y2-x2*y1)/dx
    A = y2 - y1
    B = dx
    C = (x2*y1-x1*y2)
    return A,B,C,k,b
twopaline = twopointoneline    # 两点一线的别名
twodotaline = twopointoneline

def point_is_on_line(point,line):
    """判断点是否在直线上,point:二元组表示的点，line:两个点表示的直线"""
    P,Q = line
    A,B,C,k,b = twopointoneline(P,Q) # 直线方程标准式,k斜率,b截距
    #print("A,B,C,k,b",A,B,C,k,b)
    x,y = point
    #print("x y = ",x,y)
    return abs(A*x + B*y + C)<0.00000001     # 符合直线标准方程则返回真，否则假        
dot_is_on_line = point_is_on_line

def point_is_on_segment(point,segment):
    """判断点是否在线段上,
       point:二元组表示的点,segment:两个点表示的线段,如((10,10),(20,20))或[(0,0),(100,100)]"""
    P,Q = segment    
    x,y = point
    if point_is_on_line(point,segment):   # 如果在直线上,进一步判断是否在线段上
        x1 = P[0];x2 = Q[0] # 线段1的两个x坐标
        if x1>x2:x1,x2 = x2,x1         # 如果x1比x2大,则交换x1和x2的值
        if x>x2 or xy2:y1,y2 = y2,y1         # 如果y1比y2大,则交换y1和y2的值
        if y>y2 or y
							

"""
 点转图像测试程序,本程序是为在python海龟绘图中使用洪水填充而作的一个中间研究程序,作者李兴球.
"""
import cv2
import turtle
import numpy as np

def convert_turtle_xy(pos,w,h,img_w,img_h):
    """pos是以左上角为原点,向右为正x,向下为正y的坐标,函数把它转换成turtle坐标"""
    x,y = pos
    x = x - img_w//2    
    y = -y+ img_h//2
    return x,y

def points2image(points):
    """坐标点转换为灰图像,x->,y向下为正"""
    min_x = min([x for x,y in points])
    max_x = max([x for x,y in points])
    min_y = min([y for x,y in points])
    max_y = max([y for x,y in points])
    left,top = min_x,min_y
    width = max_x - min_x +1
    height = max_y - min_y +1
    image = [[255 for i in range(width)] for j in range(height)] 
    new_points = [(x-left,y-top) for x,y in points]
    #print('new_points=',new_points)
    #for row in image:
    #    print(row)
    for i in range(height):
        for j in range(width):
            if (j,i) in new_points:
                image[i][j] = 0
    return image

# 这些坐标点是以左上角为原点的,(x向右为正,y轴向下为正)
A = (10,5);B=(10,200);C=(150,150);D=(200,100);E=(300,300);F=(330,330)
ps = [A,B,C,D,E,F]
img = points2image(ps)
gray = np.array(img,dtype='uint8')
print(gray)
img_height,img_width = gray.shape[0:]    # 高度、宽度

ret, thresh = cv2.threshold(gray, 127, 255, cv2.THRESH_BINARY)
print(gray)
# 提取轮廓
contours, hierarchy = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)


w,h = 800,900
turtle.setup(w,h)
turtle.penup()
turtle.speed(0)
turtle.delay(0)
for item in contours:
   cors = [convert_turtle_xy(tuple(lis[0]),w,h,img_width,img_height) for lis in item]
   cors.append(convert_turtle_xy(tuple(item[0][0]),w,h,img_width,img_height))
   for x,y in cors:
       turtle.goto(x,y);turtle.dot()
       if not turtle.isdown():turtle.down()
   turtle.penup()

被疫情封在家两个礼拜了，每天有核酸检测人员上门做核酸，这个为什么总要检查，普通病去医院检一次即可。这个小病毒呢，天天要检查是否是阳性。好像总是怀疑检测不对，然后又要重新检测似的。当然不可能无限循环，不过这检测次数也太多了。外国人知道了会认为中国人是世界上最胆小的民族，以后势必成为笑柄。

总之，不看过程，只看结果，那就是我们的社会病了，社会被强行按下暂停键，让每个人思考这是为什么？
是新冠病毒吗？这是表象，显然不是由于新冠病毒。社会的发展有其规律，今年不产生新冠病毒，也会在明年产生新冠病毒，总之这个新冠病毒是一定会产生的，那么它为什么会一定会产生，这背后的逻辑是什么？

我们要通过现象看本质。我看到网上有种说法是，由于科学技术造成地球环境大污染导致生态失衡。
比如，我们地球处于石油农业阶段，即把农业发展建立在以石油、煤和天然气等能源和原料为基础，以高投资、高能耗方式经营的大型农业。这造成土地板结，土地不断退化，地球生态环境被人类破坏，地球正在经历第三次生物大灭绝。

即，现代农业就是反地球演化的。因为地球不需要人类，也能活得更好。今天编了一个程序，演示效果如上所示：
代码如下所示：

import time
import turtle

def movebus(x,y):            # for button1     
    sp = button1.shape()
    if sp!='b1.gif': return  # 如果不造型是b1.gif，是灰色，则单击无效
    button1.shape('b1_disable.gif')
    button2.shape('b2_disable.gif')     
    button1.onclick(None)
    turtle.clear()
    turtle.write('演示中...',align='center',font=('',12,'normal'))
    while bus.xcor()<340:
        bus.fd(10)
        time.sleep(0.01)
    bus.setx(-340)
    button1.onclick(movebus)
    button1.shape('b1.gif')
    button2.shape('b2.gif')
    turtle.clear()
    turtle.write('演示完毕...',align='center',font=('',12,'normal'))     

def movebg(x,y):               # for button2     
    pass

 
turtle.setup(480,360)
turtle.delay(0)
turtle.bgpic('city_960x360.gif')
turtle.title('汽车行驶与相对运动演示动画')
turtle.ht()
turtle.penup()
turtle.speed(0)
turtle.sety(150)
turtle.color('magenta')

sc = turtle.getscreen()
root = sc._root
root.resizable(0,0)          # 关闭缩放

sc.addshape('b1.gif')        # 添加造型
sc.addshape('b2.gif')
sc.addshape('b1_disable.gif')
sc.addshape('b2_disable.gif')
sc.addshape('bus.gif')
cv = turtle.getcanvas()      # 获取画布

bus = turtle.Turtle('bus.gif')
bus.penup()
bus.speed(0)
bus.goto(-340,-100)

button1 = turtle.Turtle('b1.gif')
button1.penup()
button1.speed(0)
button1.bk(100)
button1.onclick(movebus)    # 绑定事件

button2 = turtle.Turtle('b2_disable.gif')
button2.penup()
button2.speed(0)
button2.fd(100)
button2.onclick(movebg)

sc.mainloop()
 

请同学们完成如图所示功能，把下面代码完善即可：

import random
import turtle

def fill_square(x,y):
    """x,y是小正方形内随机的一个坐标,如果刚好在左边上,则填充右边的小正方形,如果刚好在下边上,则填充上边的小正方形,填充颜色随机"""
        
turtle.speed(0)
turtle.delay(0)
turtle.dot(10,'red')
turtle.penup()
turtle.goto(-250,250)

for i in range(11):
    turtle.pd()
    turtle.fd(500)
    turtle.bk(500)
    turtle.pu()
    turtle.right(90)
    turtle.fd(50)
    turtle.left(90)

turtle.penup()
turtle.goto(-250,250)
turtle.right(90)
for i in range(11):
    turtle.pd()
    turtle.fd(500)
    turtle.bk(500)
    turtle.pu()
    turtle.left(90)
    turtle.fd(50)
    turtle.rt(90)
turtle.penup()
turtle.home()
turtle.ht()

screen = turtle.Screen()
screen.onclick(lambda x,y:fill_square(x,y))  # 单击会调用fill_square函数在x,y处进行填充
screen.mainloop()

一个基本程序，把它应用起来价值就大了，具体发挥看你自己，这可是个秘密，不过一般人无法识别。

import time
import turtle

for i in range(4):
    turtle.fd(100)
    turtle.left(90)

turtle.fd(150)
turtle.penup()

turtle.fillcolor('red')
turtle.begin_fill()
for i in range(4):
    turtle.fd(100)
    turtle.left(90)
turtle.end_fill()

t = turtle.getturtle()
k = t.items[-1]

cv = turtle.getcanvas()
for i in range(200):
    cv.move(k,-1,1)
    cv.update()
    time.sleep(0.01)

#海龟碰到线条就停止了(也是为了bloodfill漫水填充而编的测试程序)
import turtle

cv = turtle.getcanvas()
turtle.shape('circle')
turtle.shapesize(0.2)
 
turtle.circle(100)

turtle.penup()
turtle.sety(50)
running = True
while running:
    turtle.fd(1)
    all_items = cv.find_all()
    for item in all_items:
        zt = cv.itemconfig(item)['state'][-1]
        if zt=='hidden':continue
        selfitem = turtle.getturtle().turtle._item
        x1,y1,x2,y2 = cv.bbox(selfitem)
        ss = cv.find_overlapping(x1,y1,x2,y2)
        ss = set(ss)
        ss.remove(selfitem)
        if ss:running = False
        
x,y = 100,100
cv.create_rectangle(x,y,x,y,outline="red")
x,y = 200,100
cv.create_line(x,y,x+1,y+1,width=1,fill="red")

以下程序是BUG程序，填充不完整，填充采用fill4即4方向填充，速度也慢，图像大了会有stack溢出，本人只是用来测试。

import turtle

def get_pixel_color(canvas, x, y):
    ids = canvas.find_overlapping(x, y, x, y)

    if len(ids) > 0:                 # 说明画布上有item,取最上面的item 
        item = ids[-1]
       
        color = canvas.itemcget(item,"fill") # 获取这个item的fill填充颜色
        color = color.upper()
        if color != '':r,g,b = canvas.winfo_rgb(color)
    else:                            # 否则画布上这个位置没有item,则取背景色     
        r,g,b = canvas.winfo_rgb(canvas._canvas.config('bg')[-1])
    r,g,b = r>>8,g>>8,b>>8
    return r,g,b
    
def fill(canvas,x,y,oldcolor,newcolor):
  
     if y<=abs(height//2) and x<=abs(width//2):
          y = -y
          ss = None
          all_items = cv.find_all()
          for item in all_items:
             zt = cv.itemconfig(item)['state'][-1]
             if zt=='hidden':continue
             ss = cv.find_overlapping(x,y,x,y)
             #print('ss=,',ss)
             if ss:break
         
          if ss == None or (isinstance(ss,tuple) and len(ss)==0 ):
              
             se = get_pixel_color(canvas, x,y)
            #print('se=',se)
             if se == oldcolor:
                i = cv.create_line(x,y,x+1,y+1,width=1,fill=newcolor)
                #print(cv.coords(i))
                cv.update()
                fill(canvas ,x,-y+1,oldcolor,newcolor)
                fill(canvas ,x,-y-1,oldcolor,newcolor)
                fill(canvas ,x+1,-y,oldcolor,newcolor)
                fill(canvas ,x-1,-y,oldcolor,newcolor)

turtle.delay(0)
turtle.speed(0)
width = turtle.window_width()
height = turtle.window_height()          
cv = turtle.getcanvas()
turtle.shape('circle')
turtle.shapesize(2) 
turtle.circle(10)
turtle.ht()
fill(cv,5,5,(255,255,255),'red')

上课了,请同学们仔细阅读代码,完成发射任务,具体请见演示动画。

import time
import turtle

def shoot_b1():
    """请完善这个函数的代码"""
turtle.delay(0)
turtle.setup(480,360)

b1 = turtle.Turtle('circle')
b1.left(90)
b1.speed(0)
b1.penup()
b1.ht()

cv = turtle.getcanvas()
按钮1 = turtle.TK.Button(text='发射',command=shoot_b1)
cv.create_window(0,150,window=按钮1)

square = turtle.Turtle('square')
square.shapesize(2)
square.ht()
square.penup()
square.goto(-240,150)
square.st()
dx = 2
while True:

    square.fd(dx)
    if square.xcor()>=240:
        square.ht()
        square.goto(-240,150)
        square.st()
   pass                      # 请在这里完善代码
        
    if b1.isvisible():
        b1.fd(10)
        if b1.ycor()>180:b1.ht()
    turtle.update()
    time.sleep(0.01)

"""
  按钮事件初探_随机生成海龟.py
  
  2022年6月4号下午4点Python班课堂编程任务
  
  任务一:
  单击按钮会在随机位置生成不同颜色及大小的海龟,并放在一个字典中,
  字典的键盘就是海龟,值是它的颜色 (如果用RGB1.0模式表示颜色,那么值就是一个三元组)

  任务二:
  在按钮下面再加一个按钮,单击它后会修改成随机的背景颜色,同时所有海龟的y坐标会取反,
  即改变为原来y坐标的负数.
  
"""
import turtle

def process_click():    
    print('什么也没做')

turtle.setup(800,600)
canvas = turtle.getcanvas()

# 新建按钮,上面的文本是'点我生成海龟',单击事件是process_click
button1 = turtle.TK.Button(text=' 点 我 生 成  海 龟 ',command=process_click)
# 把按钮放在画布上,这里的坐标是以中心点为原点,但y轴向下为正!
canvas.create_window(0,150,window=button1 )


turtle.done()

这个程序的单元是定义一个画正方形的函数,以下是这个函数,其它代码自己组织即可:

import turtle

def draw_square(center,length,cc):
    """center:中心点坐标
       length:边长
       cc:填充颜色
       以center为中心点画边长为length的正方形
    """
    l2 = length/2
    turtle.goto(center)
    turtle.bk(l2)
    turtle.right(90)
    turtle.bk(l2)
    turtle.left(90)
    turtle.color(cc)
    turtle.begin_fill()
    for _ in range(4):
        turtle.fd(length)
        turtle.right(90)
    turtle.end_fill()
    turtle.right(90)
    turtle.fd(l2)
    turtle.left(90)
    turtle.fd(l2)

turtle.penup()
draw_square((-100,100),100,'red')

下面这个图形不好取什么名字,先取这个名字吧,上课时把图形显示,让学生们去练习即可.

下面是参考程序:

import turtle

cs = ['red','orange','yellow','green']

turtle.shape('turtle')
turtle.bgcolor('black')
turtle.speed(0)
turtle.delay(0)

turtle.color('white')
turtle.penup()
turtle.begin_fill()
for i in range(4):
    turtle.fd(100)
    turtle.left(90)
turtle.end_fill()

for i in range(4):
    turtle.right(90)
    turtle.color(cs[i])
    turtle.begin_fill()
    turtle.circle(50,180)
    turtle.end_fill()

turtle.ht()

“””
turtle绘的正态分布图.py
“””
import turtle
import numpy as np

datas = [int(np.random.randn()*100) for _ in range(50000)]

print(min(datas))
print(max(datas))
counts = {}
for c in range(min(datas),max(datas)+1):
freq = datas.count(c) # 每个数产生的次数
counts[c] = freq # 放在字典中,如counts[3]=50,记录了3有50个

turtle.delay(0)
turtle.speed(0)
turtle.penup()
for key,value in counts.items():
turtle.goto(key,value)
turtle.dot(4)

turtle.done()

以前编写的程序是海龟跟随鼠标指针,现在倒过来了，这是利用事件产生方法实现的。

import time
import turtle
from threading import Thread

def mouse_follow_turtle(test_turtle):
    root = test_turtle.getscreen()._root    
    while True:        
        left = test_turtle.xcor() + 400
        top = 300 - test_turtle.ycor()
        root.event_generate("",warp=True,x=left,y=top)
        time.sleep(0.1)
        
def turtle_move(test_turtle):
     while True:
        test_turtle.fd(1)
        test_turtle.left(1)
        
if __name__ == '__main__':
    
    turtle.setup(800,600)
    tom = turtle.Turtle('turtle')
    t1 = Thread(target=mouse_follow_turtle,args=(tom,))
    #t1.setDaemon(True)
    t1.start()
    t2 = Thread(target=turtle_move,args=(tom,))
    #t2.setDaemon(True)
    t2.start()   

    turtle.mainloop()
        

"""
  修改线条端点风格和拐弯样多_joinstyle和capstyle,
  有人问我如何修改线条的端点风格,这就是一个tkinter的问题,
  不过,还是要研究turtle模块才能把代码写出来,
  下面的代码演示了如何修改,顺便还有连接风格,
  所有代码如下所示:
"""
import turtle

turtle.pensize(10)
cv = turtle.getcanvas()
t = turtle.getturtle()
lid = t.currentLineItem
cv.itemconfig(lid,capstyle=turtle.TK.BUTT,
              joinstyle=turtle.TK.MITER)
t.fd(100)

t.goto(100,100)
for _ in range(4):
    turtle.fd(100)
    turtle.right(90)

参考文章: https://www.pythonstudio.us/tkinter-reference/cap-and-join-styles.html