多边形裁剪

#python实现可视化的多边形裁剪
import matplotlib.pyplot as plt
import copy
import math
from tkinter import *
def cross_point(line1,line2,winx,winy):#计算交点函数
year1 = copy.deepcopy(line1)
pop1 = copy.deepcopy(line2)
winx1 = copy.deepcopy(winx)
winy1 = copy.deepcopy(winy)
node_class = []
minx = min(winx)
maxx = max(winx)
miny = min(winy)
maxy = max(winy)
count = 0
for i in range(len(line1)-1):
count1=0
x1=line1[i]#取四点坐标
y1=line2[i]
x2=line1[i+1]
y2=line2[i+1]
k1=(y2-y1)*1.0/(x2-x1)#计算k1,由于点均为整数，需要进行浮点数转化
b1=y1*1.0-x1*k1*1.0#整型转浮点型是关键
nodey = k1*minx*1.0+b1*1.0
if (y1<=nodey<=y2 or y2<=nodey<=y1) and (miny<=nodey<=maxy) and ([maxx,nodey] not in node_class):
node_class.append([minx,nodey])
count=count+1
count1=count1+1
nodey1 = k1*maxx*1.0+b1*1.0
if (y1<=nodey1<=y2 or y2<=nodey1<=y1) and (miny<=nodey1<=maxy) and ([maxx,nodey1] not in node_class):
node_class.append([maxx,nodey1])
count=count+1
count1=count1+1
nodex = (miny*0.1 - b1*0.1)/(k1*0.1)
if (minx<=nodex<=maxx) and (x1<=nodex<=x2 or x2<=nodex<=x1) and ([nodex,miny] not in node_class):
node_class.append([nodex,miny])
count=count+1
count1=count1+1
nodex1 = (maxy*0.1 - b1*0.1)/(k1*0.1)
if (minx<=nodex1<=maxx) and (x1<=nodex1<=x2 or x2<=nodex1<=x1) and ([nodex1,maxy] not in node_class):
node_class.append([nodex1,maxy])
count=count+1
count1=count1+1
print(count1)
if count1 == 1:
year1.insert(i+count,node_class[count-1][0])
pop1.insert(i+count,node_class[count-1][1])
if count1 ==2:
if (math.fabs(node_class[count-2][0]-x1)>math.fabs(node_class[count-1][0]-x1)): n = node_class[count-2]
node_class[count-2] = node_class[count-1]
node_class[count-1] = n
year1.insert(i+count-1,round(node_class[count-2][0],5))
pop1.insert(i+count-1,node_class[count-2][1])
year1.insert(i+count,node_class[count-1][0])
pop1.insert(i+count,node_class[count-1][1])
print(year1,pop1,node_class)
return year1,pop1
def line(year,pop,year1,pop1,x,y):
minx = min(x)
maxx = max(x)
miny = min(y)
maxy = max(y)
print(minx,maxx,miny,maxy)
linex = []
liney = []
b=[]
for i in range (len(year1)-1):
if (minx<=year1[i]<=maxx) and (miny<=pop1[i]<=maxy):
b.append(i)
linex.append(year1[i])
liney.append(pop1[i])
linex.append(year1[b[0]])
liney.append(pop1[b[0]])
print(linex,liney)
return linex,liney
def run1(n,m,a,b):
n = int(n)
m = int(m)
a = int(a)
b = int(b)
year = [4,20,25,15,7,4]
pop = [2,3,1,6,5,2]
year1 = []
year2 = []
x = [n+a,n,n,n+a,n+a]
y = [m+b,m+b,m,m,m+b]
year1,pop1 = cross_point(year,pop,x,y)
linex,liney=line(year,pop,year1,pop1,x,y)
plt.plot(year,pop)
plt.plot(x,y,'r')
plt.plot(linex,liney,'b')
plt.show()
root = Tk()
root.geometry('500x240')
root.title('多边形裁剪')
lb1 = Label(root, text='请输入裁剪框右下角坐标，宽，高') lb1.place(relx=0.1, rely=0.1, relwidth=0.8, relheight=0.1)
inp1 = Entry(root)
inp1.place(relx=0.1, rely=0.2, relwidth=0.15, relheight=0.1) inp2 = Entry(root)
inp2.place(relx=0.3, rely=0.2, relwidth=0.15, relheight=0.1) inp3 = Entry(root)
inp3.place(relx=0.5, rely=0.2, relwidth=0.15, relheight=0.1) inp4 = Entry(root)
inp4.place(relx=0.7, rely=0.2, relwidth=0.15, relheight=0.1) # 方法-直接调用run1()
btn1 = Button(root, text='裁剪', command=lambda:run1(inp1.get(), inp2.get(),inp3.get(),inp4.get()))
btn1.place(relx=0.35, rely=0.4, relwidth=0.3, relheight=0.1)
root.mainloop()。