mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-27 19:48:43 +08:00
Johannes Schönberger
98 lines
2.4 KiB
Cython
98 lines
2.4 KiB
Cython
#cython: cdivision=True
|
|
#cython: boundscheck=False
|
|
#cython: nonecheck=False
|
|
#cython: wraparound=False
|
|
import numpy as np
|
|
|
|
cimport numpy as cnp
|
|
from .._shared.geometry cimport point_in_polygon, points_in_polygon
|
|
|
|
|
|
def grid_points_in_poly(shape, verts):
|
|
"""Test whether points on a specified grid are inside a polygon.
|
|
|
|
For each ``(r, c)`` coordinate on a grid, i.e. ``(0, 0)``, ``(0, 1)`` etc.,
|
|
test whether that point lies inside a polygon.
|
|
|
|
Parameters
|
|
----------
|
|
shape : tuple (M, N)
|
|
Shape of the grid.
|
|
verts : (V, 2) array
|
|
Specify the V vertices of the polygon, sorted either clockwise
|
|
or anti-clockwise. The first point may (but does not need to be)
|
|
duplicated.
|
|
|
|
See Also
|
|
--------
|
|
points_in_poly
|
|
|
|
Returns
|
|
-------
|
|
mask : (M, N) ndarray of bool
|
|
True where the grid falls inside the polygon.
|
|
|
|
"""
|
|
cdef double[:] vx, vy
|
|
verts = np.asarray(verts)
|
|
|
|
vx = verts[:, 0].astype(np.double)
|
|
vy = verts[:, 1].astype(np.double)
|
|
cdef Py_ssize_t V = vx.shape[0]
|
|
|
|
cdef Py_ssize_t M = shape[0]
|
|
cdef Py_ssize_t N = shape[1]
|
|
cdef Py_ssize_t m, n
|
|
|
|
cdef cnp.ndarray[dtype=cnp.uint8_t, ndim=2, mode="c"] out = \
|
|
np.zeros((M, N), dtype=np.uint8)
|
|
|
|
for m in range(M):
|
|
for n in range(N):
|
|
out[m, n] = point_in_polygon(V, &vx[0], &vy[0], m, n)
|
|
|
|
return out.view(bool)
|
|
|
|
|
|
def points_in_poly(points, verts):
|
|
"""Test whether points lie inside a polygon.
|
|
|
|
Parameters
|
|
----------
|
|
points : (N, 2) array
|
|
Input points, ``(x, y)``.
|
|
verts : (M, 2) array
|
|
Vertices of the polygon, sorted either clockwise or anti-clockwise.
|
|
The first point may (but does not need to be) duplicated.
|
|
|
|
See Also
|
|
--------
|
|
grid_points_in_poly
|
|
|
|
Returns
|
|
-------
|
|
mask : (N,) array of bool
|
|
True if corresponding point is inside the polygon.
|
|
|
|
"""
|
|
cdef double[:] x, y, vx, vy
|
|
|
|
points = np.asarray(points)
|
|
verts = np.asarray(verts)
|
|
|
|
x = points[:, 0].astype(np.double)
|
|
y = points[:, 1].astype(np.double)
|
|
|
|
vx = verts[:, 0].astype(np.double)
|
|
vy = verts[:, 1].astype(np.double)
|
|
|
|
cdef cnp.ndarray[cnp.uint8_t, ndim=1] out = \
|
|
np.zeros(x.shape[0], dtype=np.uint8)
|
|
|
|
points_in_polygon(vx.shape[0], &vx[0], &vy[0],
|
|
x.shape[0], &x[0], &y[0],
|
|
<unsigned char*>out.data)
|
|
|
|
return out.astype(bool)
|
|
|