fr/fr_env/lib/python3.8/site-packages/skimage/draw/_polygon2mask.py

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2021-02-17 12:26:31 +05:30
import numpy as np
from . import draw
def polygon2mask(image_shape, polygon):
"""Compute a mask from polygon.
Parameters
----------
image_shape : tuple of size 2.
The shape of the mask.
polygon : array_like.
The polygon coordinates of shape (N, 2) where N is
the number of points.
Returns
-------
mask : 2-D ndarray of type 'bool'.
The mask that corresponds to the input polygon.
Notes
-----
This function does not do any border checking, so that all
the vertices need to be within the given shape.
Examples
--------
>>> image_shape = (128, 128)
>>> polygon = np.array([[60, 100], [100, 40], [40, 40]])
>>> mask = polygon2mask(image_shape, polygon)
>>> mask.shape
(128, 128)
"""
polygon = np.asarray(polygon)
vertex_row_coords, vertex_col_coords = polygon.T
fill_row_coords, fill_col_coords = draw.polygon(
vertex_row_coords, vertex_col_coords, image_shape)
mask = np.zeros(image_shape, dtype=bool)
mask[fill_row_coords, fill_col_coords] = True
return mask