Validate that polygon has at least 1 vertex in geometry utils.py

[ablazejuk]

Description

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List any dependencies that are required for this change.

Type of change

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• New feature (non-breaking change which adds functionality)

How has this change been tested, please provide a testcase or example of how you tested the change?

Just added a validation

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Docs

• Docs updated? What were the changes:

[CLAassistant]

All committers have signed the CLA.

[LinasKo]

Hi @ablazejuk 👋

I'll have a quick look and merge this soon. It's great when we can replace OpenCV errors with more meaningful messages.

[LinasKo]

Upon closer inspection, the method works fine with 1 and 2 points, and emits warnings when no points are passed. There is a possible rounding issue, but the update for polygon is slightly different than the one proposed.

Test code:

import supervision as sv
import numpy as np

polygon_0 = np.array([], dtype=np.float32).reshape(0, 2)
polygon_1 = np.array([[1, 1]], dtype=np.float32)
polygon_2 = np.array([[1, 1], [2, 2]], dtype=np.float32)
polygon_3 = np.array([[1, 1], [2, 1], [2, 2]], dtype=np.float32)
polygon_4 = np.array([[1, 1], [2, 1], [2, 1], [1, 2]], dtype=np.float32)

try:
    center_0 = sv.get_polygon_center(polygon_0)
except ValueError as e:
    print(e)

center_1 = sv.get_polygon_center(polygon_1)
center_2 = sv.get_polygon_center(polygon_2)
center_3 = sv.get_polygon_center(polygon_3)
center_4 = sv.get_polygon_center(polygon_4)

try:
    print(center_0)
except NameError:
    pass

print(center_1)
print(center_2)
print(center_3)
print(center_4)

[LinasKo]

Thank you for the contribution @ablazejuk!