mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-28 17:51:07 +08:00
Steven Silvester
09876408fc
Fix some sphinx warnings Add documentation build to test Add documentation build to test Remove change in numpydoc Remove change in apigen Add makefile target for html and add to travis script Add a makefile target for html and add to travis script Fix more sphinx warnings
168 lines
5.1 KiB
Python
168 lines
5.1 KiB
Python
# coding: utf-8
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import numpy as np
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from ._draw import _coords_inside_image
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def _ellipse_in_shape(shape, center, radiuses):
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"""Generate coordinates of points within ellipse bounded by shape."""
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y, x = np.ogrid[0:float(shape[0]), 0:float(shape[1])]
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cy, cx = center
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ry, rx = radiuses
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distances = ((y - cy) / ry) ** 2 + ((x - cx) / rx) ** 2
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return np.nonzero(distances < 1)
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def ellipse(cy, cx, yradius, xradius, shape=None):
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"""Generate coordinates of pixels within ellipse.
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Parameters
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----------
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cy, cx : double
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Centre coordinate of ellipse.
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yradius, xradius : double
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Minor and major semi-axes. ``(x/xradius)**2 + (y/yradius)**2 = 1``.
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shape : tuple, optional
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Image shape which is used to determine the maximum extent of output pixel
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coordinates. This is useful for ellipses which exceed the image size.
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By default the full extent of the ellipse are used.
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Returns
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-------
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rr, cc : ndarray of int
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Pixel coordinates of ellipse.
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May be used to directly index into an array, e.g.
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``img[rr, cc] = 1``.
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Examples
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--------
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>>> from skimage.draw import ellipse
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>>> img = np.zeros((10, 10), dtype=np.uint8)
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>>> rr, cc = ellipse(5, 5, 3, 4)
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>>> img[rr, cc] = 1
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>>> img
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array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
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[0, 0, 0, 1, 1, 1, 1, 1, 0, 0],
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[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
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[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
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[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
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[0, 0, 0, 1, 1, 1, 1, 1, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
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"""
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center = np.array([cy, cx])
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radiuses = np.array([yradius, xradius])
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if shape is not None:
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return _ellipse_in_shape(shape, center, radiuses)
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else:
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# rounding here is necessary to avoid rounding issues later
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upper_left = np.floor(center - radiuses).astype(int)
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shifted_center = center - upper_left
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# Shifted center is in interval [radiuses, radiuses + 1], so
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# the ellipse must fit in [0, 2*radiuses + 1].
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bounding_shape = np.ceil(2 * radiuses + 1)
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rr, cc = _ellipse_in_shape(bounding_shape, shifted_center, radiuses)
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rr.flags.writeable = True
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cc.flags.writeable = True
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rr += upper_left[0]
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cc += upper_left[1]
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return rr, cc
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def circle(cy, cx, radius, shape=None):
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"""Generate coordinates of pixels within circle.
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Parameters
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----------
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cy, cx : double
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Centre coordinate of circle.
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radius: double
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Radius of circle.
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shape : tuple, optional
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Image shape which is used to determine the maximum extent of output pixel
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coordinates. This is useful for circles which exceed the image size.
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By default the full extent of the circle are used.
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Returns
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-------
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rr, cc : ndarray of int
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Pixel coordinates of circle.
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May be used to directly index into an array, e.g.
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``img[rr, cc] = 1``.
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Notes
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-----
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This function is a wrapper for skimage.draw.ellipse()
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Examples
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--------
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>>> from skimage.draw import circle
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>>> img = np.zeros((10, 10), dtype=np.uint8)
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>>> rr, cc = circle(4, 4, 5)
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>>> img[rr, cc] = 1
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>>> img
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array([[0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
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[0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
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[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
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[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
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[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
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[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
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[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
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[0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
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[0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
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"""
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return ellipse(cy, cx, radius, radius, shape)
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def set_color(img, coords, color):
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"""Set pixel color in the image at the given coordinates.
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Coordinates that exceed the shape of the image will be ignored.
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Parameters
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----------
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img : (M, N, D) ndarray
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Image
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coords : ((P,) ndarray, (P,) ndarray)
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Coordinates of pixels to be colored.
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color : (D,) ndarray
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Color to be assigned to coordinates in the image.
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Returns
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-------
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img : (M, N, D) ndarray
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The updated image.
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Examples
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--------
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>>> from skimage.draw import line, set_color
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>>> img = np.zeros((10, 10), dtype=np.uint8)
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>>> rr, cc = line(1, 1, 20, 20)
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>>> set_color(img, (rr, cc), 1)
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>>> img
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array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
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[0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
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[0, 0, 1, 0, 0, 0, 0, 0, 0, 0],
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[0, 0, 0, 1, 0, 0, 0, 0, 0, 0],
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[0, 0, 0, 0, 1, 0, 0, 0, 0, 0],
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[0, 0, 0, 0, 0, 1, 0, 0, 0, 0],
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[0, 0, 0, 0, 0, 0, 1, 0, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 1, 0, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 1, 0],
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[0, 0, 0, 0, 0, 0, 0, 0, 0, 1]], dtype=uint8)
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"""
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rr, cc = coords
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rr, cc = _coords_inside_image(rr, cc, img.shape)
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img[rr, cc] = color
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