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added draw circle and ellipse functions

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This commit is contained in:
Johannes Schönberger
2012-04-23 16:20:49 +02:00
parent 7191eaf058
commit de8369be50
3 changed files with 119 additions and 2 deletions
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skimage/draw/_draw.pyx
+65
View File
@@ -1,5 +1,6 @@
import numpy as np
import math
from libc.math cimport sqrt
cimport numpy as np
cimport cython
@@ -121,3 +122,67 @@ def polygon(verts, shape=None):
cc.append(c)
return np.array(rr), np.array(cc)
@cython.boundscheck(False)
@cython.wraparound(False)
@cython.nonecheck(False)
@cython.cdivision(True)
def ellipse(double cy, double cx, double b, double a, shape=None):
"""Generate coordinates of pixels within ellipse.
Parameters
----------
cy, cx : double
centre coordinate of ellipse
b, a: double
minor and major semi-axes. (x/a)**2 + (y/b)**2 = 1
Returns
-------
rr, cc : ndarray of int
Pixel coordinates of ellipse.
May be used to directly index into an array, e.g.
``img[rr, cc] = 1``.
"""
cdef int minr = <int>max(0, cy-b)
cdef int maxr = <int>math.ceil(cy+b)
cdef int minc = <int>max(0, cx-a)
cdef int maxc = <int>math.ceil(cx+a)
# make sure output coordinates do not exceed image size
if shape is not None:
maxr = min(shape[0]-1, maxr)
maxc = min(shape[1]-1, maxc)
cdef int r, c
#: output coordinate arrays
rr = list()
cc = list()
for r in range(minr, maxr+1):
for c in range(minc, maxc+1):
if sqrt(((r - cy)/b)**2 + ((c - cx)/a)**2) < 1:
rr.append(r)
cc.append(c)
return np.array(rr), np.array(cc)
def circle(double cy, double cx, double radius, shape=None):
"""Generate coordinates of pixels within circle.
Parameters
----------
cy, cx : double
centre coordinate of circle
radius: double
radius of circle
Returns
-------
rr, cc : ndarray of int
Pixel coordinates of ellipse.
May be used to directly index into an array, e.g.
``img[rr, cc] = 1``.
"""
return ellipse(cy, cx, radius, radius, shape)
skimage/draw/draw.py
+1 -1
View File
@@ -3,4 +3,4 @@ Methods to draw on arrays.
"""
from ._draw import bresenham, polygon
from ._draw import bresenham, polygon, ellipse, circle
skimage/draw/tests/test_draw.py
+53 -1
View File
@@ -1,7 +1,7 @@
from numpy.testing import assert_array_equal
import numpy as np
from skimage.draw import bresenham, polygon
from skimage.draw import bresenham, polygon, circle, ellipse
def test_bresenham_horizontal():
@@ -116,6 +116,58 @@ def test_polygon_exceed():
assert_array_equal(img, img_)
def test_circle():
img = np.zeros((15, 15), 'uint8')
rr, cc = circle(7, 7, 6)
img[rr,cc] = 1
img_ = np.array(
[[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0],
[0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0],
[0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
)
assert_array_equal(img, img_)
def test_ellipse():
img = np.zeros((15, 15), 'uint8')
rr, cc = ellipse(7, 7, 3, 7)
img[rr,cc] = 1
img_ = np.array(
[[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
)
assert_array_equal(img, img_)
if __name__ == "__main__":
from numpy.testing import run_module_suite