I am trying to write an algorithm using turtle. The turtle is bouncing in a polygon, and painting a portion of the edge it touches. The algorithm should terminate once there are no unpainted areas left on the boundary of the polygon.

In order to do that, I need to check every edge of the polygon and determine whether it is completely painted.

Is there such a function in turtle library? If not, then what is a simple method to determine this? The polygon is not necessarily rectilinear.

Here is a MWE:

import turtle
from sympy import Segment, Point, Ray, N
from mpmath import radians

turtle.setworldcoordinates(-1, -1, 11, 11)
paint_len = 1


        


def paint(e, hit):
    print(hit)
    turtle.tracer(False)
    a.penup()
    a.goto(hit)
    a.setheading(a.towards(N(e.p1.x), N(e.p1.y)))
    dist = min(N(Point(a.pos()).distance(e.p1)), paint_len/2)
    a.forward(dist)
    dist = min(N(Point(a.pos()).distance(e.p2)), paint_len)
    a.setheading(a.towards(N(e.p2.x), N(e.p2.y)))
    a.pendown()
    a.forward(dist)
    a.penup()
    turtle.tracer(True)

t = turtle.Turtle()
a = turtle.Turtle()
a.hideturtle()
a.width(3)

turtle.tracer(False)
p1 = (0,0)
p2 = (10,0)
p3 = (10,10)
p4 = (0,10)
E = [Segment(p1, p2), Segment(p2,p3), Segment(p3,p4), Segment(p4,p1)]

def completely_painted(e):
    a.goto(N(e.p1.x), N(a.p1.y))
    a.setheading(a.towards(N(e.p2.x), N(e.p2.y)))
    a.goto(N(e.p2.x), N(e.p2.y))
    #if a passed through non-painted part:
    #   return False
    return True

def all_edges_painted():
    for e in E:
        if not completely_painted(e):
            return False
    return True


t.penup()
t.goto(p1)
t.pendown()
for p in [p2, p3, p4, p1]:
    t.goto(p)
t.penup()
t.goto(5,5)
t.setheading(60)
t.pendown()
pos = Point(t.pos())
vec = Ray(pos, angle=radians(t.heading()))
ctr = 0
k = 0
p = -1
turtle.tracer(True)
t.speed(10)
a.color('red')
while True:
    for e in E:
        intersections = vec.intersection(e)
        if len(intersections) > 0:
            hit = None
            for i in intersections:
                if isinstance(i, Point):
                    hit = i
            if hit == None:
                continue
            
            ln = e.perpendicular_line(hit)
            pt = ln.projection(pos)
            normal = Ray(hit, pt) 
            t.goto(hit)
            paint(e, N(hit))
            rotate = 2 * t.towards(pt.x, pt.y) - 180 - t.heading()
            t.setheading(rotate)
            if k == 0:
                k = 1
            elif k == 1:
                k = 0
        pos = Point(t.pos())
        vec = Ray(pos, angle=radians(t.heading()))
    if ctr >= 50: # this should be if all_edges_painted()
        break
    ctr += 1

turtle.exitonclick()
turtle.done()

I commented out the parts where the method to check whether all edges are covered goes.