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# Copyright (c) 2016 Weitian LI <liweitianux@live.com>
# MIT license
#
##############################################################################
# Copyright (C) 2011, the scikit-image team
# All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
# 3. Neither the name of skimage nor the names of its contributors may be
# used to endorse or promote products derived from this software without
# specific prior written permission.
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
# IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
"""
Generic drawers (a.k.a. painters) that draw some commonly used shapes.
DISCLAIMER
----------
The following functions are taken from project [scikit-image]_, which are
licensed under the *Modified BSD* license:
- ``_ellipse_in_shape()``
- ``ellipse()``
- ``circle()``
Credits
-------
.. [scikit-image] skimage.draw.draw
http://scikit-image.org/docs/dev/api/skimage.draw.html
https://github.com/scikit-image/scikit-image/blob/master/skimage/draw/draw.py
"""
import numpy as np
def _ellipse_in_shape(shape, center, radii):
"""Generate coordinates of points within the ellipse bounded by shape."""
r_lim, c_lim = np.ogrid[0:float(shape[0]), 0:float(shape[1])]
r_o, c_o = center
r_r, c_r = radii
distances = ((r_lim - r_o) / r_r)**2 + ((c_lim - c_o) / c_r)**2
return np.nonzero(distances < 1.0)
def ellipse(r, c, r_radius, c_radius, shape=None):
"""Generate coordinates of pixels within the ellipse.
Parameters
----------
r, c : float
Center coordinate of the ellipse.
r_radius, c_radius : float
Minor and major semi-axes. ``(r/r_radius)**2 + (c/c_radius)**2 = 1``.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output
pixel coordinates. This is useful for ellipses that exceed the image
size. If None, the full extent of the ellipse is used.
Returns
-------
rr, cc : integer `~numpy.ndarray`
Pixel coordinates of the ellipse.
May be used to directly index into an array, e.g.
``img[rr, cc] = 1``.
Examples
--------
>>> from fg21sim.utils.draw import ellipse
>>> img = np.zeros((10, 10), dtype=np.uint8)
>>> rr, cc = ellipse(5, 5, 3, 4)
>>> img[rr, cc] = 1
>>> img
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, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 0, 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]], dtype=uint8)
"""
center = np.array([r, c])
radii = np.array([r_radius, c_radius])
# The upper_left and lower_right corners of the
# smallest rectangle containing the ellipse.
upper_left = np.ceil(center - radii).astype(int)
lower_right = np.floor(center + radii).astype(int)
if shape is not None:
# Constrain upper_left and lower_right by shape boundary.
upper_left = np.maximum(upper_left, np.array([0, 0]))
lower_right = np.minimum(lower_right, np.array(shape[:2]) - 1)
shifted_center = center - upper_left
bounding_shape = lower_right - upper_left + 1
rr, cc = _ellipse_in_shape(bounding_shape, shifted_center, radii)
rr.flags.writeable = True
cc.flags.writeable = True
rr += upper_left[0]
cc += upper_left[1]
return rr, cc
def circle(r, c, radius, shape=None):
"""Generate coordinates of pixels within the circle.
Parameters
----------
r, c : float
Center coordinate of the circle.
radius : float
Radius of the circle.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output
pixel coordinates. This is useful for circles that exceed the image
size. If None, the full extent of the circle is used.
Returns
-------
rr, cc : integer `~numpy.ndarray`
Pixel coordinates of the circle.
May be used to directly index into an array, e.g.
``img[rr, cc] = 1``.
Examples
--------
>>> from fg21sim.utils.draw import circle
>>> img = np.zeros((10, 10), dtype=np.uint8)
>>> rr, cc = circle(4, 4, 5)
>>> img[rr, cc] = 1
>>> img
array([[0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
[0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
"""
return ellipse(r, c, radius, radius, shape)
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