"""
Python 3, tkinter, Нарисовать ромб по введенной стороне и тупому углу.

"""

from tkinter import *
import math as m

def click():
    try:
        a = int(entr1.get())# сторона
        ang = int(entr2.get())# тупой угол
        aa = ang/2
        bb = 90-aa
        aB = (45-bb)*m.pi/180
        aD = (45+bb)*m.pi/180
        A = [5,5]
        B = [int(A[0]+a*m.cos(aB)), int(A[1]+a*m.sin(aB))]
        C = [int(B[0]+a*m.cos(aD)), int(B[1]+a*m.sin(aD))]
        D = [int(A[0]+a*m.cos(aD)), int(A[1]+a*m.sin(aD))]

        canv.delete('all')
        canv.create_line(A[0],A[1], B[0], B[1])
        canv.create_line(B[0],B[1], C[0], C[1])
        canv.create_line(C[0],C[1], D[0], D[1])
        canv.create_line(D[0],D[1], A[0], A[1])
    except:
        entr1.delete(0,END)
        entr2.delete(0,END)
        print('Error')

def focus(event):
    widget = wnd.focus_get()
    print(widget, 'has focus')

def entr2_foc(event):
    entr2.focus_set()

def b1_foc(event):
    B1.focus_set()

def entr1_foc(event):
    click()
    entr1.focus_set()



wnd = Tk()
canv = Canvas(wnd, width=200,height=200,background='white')
canv.grid(row=0, columnspan=2)

entr1 = Entry(wnd, width=5)
entr1.grid(row=1,column=0, sticky=W)
entr1.focus()
entr1.bind('<Return>', entr2_foc)
L1 = Label(wnd, text='Сторона')
L1.grid(row=1,column=1, sticky=W)

entr2 = Entry(wnd, width=5)
entr2.grid(row=2,column=0, sticky=W)
entr2.bind('<Return>', b1_foc)
L2=Label(wnd, text='Тупой Угол (градусы)')
L2.grid(row=2,column=1, sticky=W)

B1 = Button(wnd, text='GO', command=click)
B1.grid(row=3, sticky=W)
B1.bind('<Return>', entr1_foc)



wnd.mainloop()