from sprites import incenter,Sprite,Screen,perpendicular_foot
screen = Screen()
screen.xy_grid()
A = (100,100)
B = (0,0)
C = (200,-200)
# D是三角形ABC的内心,也是内切圆的圆心
D = incenter(A,B,C)
# E是D点向AC线段作垂线的垂足点。
E = perpendicular_foot(D,(A,C))
bug = Sprite()
bug.draw_line(A,B)
bug.draw_line(C,B)
bug.draw_line(A,C)
# 连线DE,也是内切圆的一条半径
radius = bug.draw_line(D,E)
bug.heading(D) # 朝向D点
bug.right(90)
bug.pendown() # 落笔
bug.circle(radius)# 画内切圆
bug.penup()
screen.mainloop()
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