[Python] Find NFP for container and polygon with pyclipper library

I'm playing with the library and trying to build an NFP polygon that shows possible positions of a figure inside a container. But my code doesn't give the result I need. The code is below. If anyone has experience with such a library, tell me what's wrong with me?

import pyclipper
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon as MplPolygon
from matplotlib.collections import PatchCollection


# Функция проверки и кооретировки замкнутости полигона
def close_poly(polygon):
if not polygon:
return []
if len(polygon) < 2:
return polygon
if polygon[0] != polygon[-1]:
return polygon + [polygon[0]]
return polygon


# Функция корректировки направления полигона
def orient_poly(polygon, ccw=False):
if len(polygon) < 3:
return polygon

area = sum(
(x1 * y2) - (x2 * y1)
for (x1, y1), (x2, y2) in zip(polygon, polygon[1:] + [polygon[0]])
)

is_currently_ccw = area < 0
return list(reversed(polygon)) if (ccw ^ is_currently_ccw) else polygon


# Функция отражения полигона относительно центра масс (центроида)
def reflect_poly(polygon):
# Вычисляем центроид
centroid = (
sum(x for x, y in polygon) / len(polygon),
sum(y for x, y, in polygon) / len(polygon),
)

# Возвращаем отраженный полигон
return [(2 * centroid[0] - x, 2 * centroid[1] - y) for x, y in polygon]


# Функция масштабирования полигона
def scale_poly(polygon, scale=100):
return [(int(x * scale), int(y * scale)) for x, y in polygon]


# Функция нахождения NFP для контейнера и полигона
def nfp_container_poly(cont, poly):
# Масштаб скалирования
SCALE = 1000

# Проверяем замкнутость полигонов
cont = close_poly(cont)
poly = close_poly(poly)

# Корректируем ориентацию контейнера и фигуры
cont = orient_poly(cont, ccw=True)
poly = orient_poly(poly, ccw=False)

# Отражаем полигон относительно центра масс
r_poly = reflect_poly(poly)

# Масштабируем полигоны
c_scaled = scale_poly(cont, SCALE)
r_scaled = scale_poly(r_poly, SCALE)

# Вычисляем разность Минковского
pc = pyclipper.Pyclipper()
pc.AddPath(c_scaled, pyclipper.PT_SUBJECT, closed=True)
pc.AddPath(r_scaled, pyclipper.PT_CLIP, closed=True)

# Получаем результат
solution = pc.Execute(
# pyclipper.CT_DIFFERENCE, pyclipper.PFT_NONZERO, pyclipper.PFT_NONZERO
pyclipper.CT_INTERSECTION,
pyclipper.PFT_NONZERO,
pyclipper.PFT_NONZERO,
)
if not solution:
return None

nfp_scaled = solution[0]
nfp = scale_poly(nfp_scaled, 1 / SCALE)

return nfp


def vizualize_poly(cont, poly, nfp):
fig, ax = plt.subplots(figsize=(10, 8))
ax.set_aspect("equal")
ax.grid(True)

cont = close_poly(cont)
poly = close_poly(poly)

# Создаем патчи для отрисовки
patches = []

# Контейнер — синий полиигон
patches.append(MplPolygon(cont, closed=True, color="blue", alpha=0.0))

# Деталь — зеленый полиигон
patches.append(MplPolygon(poly, closed=True, color="green", alpha=0.5))

# NFP — красный
if nfp:
nfp = close_poly(nfp)
patches.append(MplPolygon(nfp, closed=True, color="red", alpha=0.5))

# Добавляем патчи на график
for patch in patches:
ax.add_patch(patch)

# Добавляем легенду
legend_elements = [
plt.Rectangle((0, 0), 1, 1, fc="blue", alpha=0.5, label="Container"),
plt.Rectangle((0, 0), 1, 1, fc="green", alpha=0.5, label="Polygon"),
]

if nfp:
legend_elements.append(
plt.Rectangle((0, 0), 1, 1, fc="red", alpha=0.5, label="NFP")
)

ax.legend(handles=legend_elements, loc="upper right")

# Устанавливаем границы графика
all_points = cont + poly
if nfp:
all_points += nfp

x_coords, y_coords = zip(*all_points)
ax.set_xlim(min(x_coords) - 1, max(x_coords) + 1)
ax.set_ylim(min(y_coords) - 1, max(y_coords) + 1)

plt.title("No-Fit Polygon Visualization")
plt.show()


container = [(0, 0), (600, 0), (600, 600), (0, 600)]
polygon_a = [(0, 0), (200, 0), (200, 200), (0, 200)]

nfp = nfp_container_poly(container, polygon_a)

print(nfp)
vizualize_poly(container, polygon_a, nfp)



I need find NFP polygon_a inside container

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