mirror of
https://github.com/wassname/scikit-image.git
synced 2026-07-28 11:25:42 +08:00
Implement faster version of circle and ellipse drawing
This commit is contained in:
Johannes Schönberger
@@ -1,5 +1,5 @@
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from ._draw import line, polygon, ellipse, ellipse_perimeter, \
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circle, circle_perimeter, set_color, bresenham
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from .draw import circle, ellipse, set_color
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from ._draw import line, polygon, ellipse_perimeter, circle_perimeter
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__all__ = ['line',
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'polygon',
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@@ -7,5 +7,4 @@ __all__ = ['line',
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'ellipse_perimeter',
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'circle',
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'circle_perimeter',
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'set_color',
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'bresenham']
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'set_color']
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@@ -8,7 +8,6 @@ import numpy as np
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cimport numpy as cnp
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from libc.math cimport sqrt
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from skimage._shared.geometry cimport point_in_polygon
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from skimage._shared.utils import deprecated
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def line(Py_ssize_t y, Py_ssize_t x, Py_ssize_t y2, Py_ssize_t x2):
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@@ -74,9 +73,6 @@ def line(Py_ssize_t y, Py_ssize_t x, Py_ssize_t y2, Py_ssize_t x2):
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return rr, cc
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bresenham = deprecated('skimage.draw.line')(line)
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def polygon(y, x, shape=None):
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"""Generate coordinates of pixels within polygon.
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@@ -133,82 +129,6 @@ def polygon(y, x, shape=None):
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return np.array(rr, dtype=np.intp), np.array(cc, dtype=np.intp)
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def ellipse(double cy, double cx, double yradius, double 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 maximum extents 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 extents 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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"""
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cdef Py_ssize_t minr = int(max(0, cy - yradius))
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cdef Py_ssize_t maxr = int(math.ceil(cy + yradius))
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cdef Py_ssize_t minc = int(max(0, cx - xradius))
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cdef Py_ssize_t maxc = int(math.ceil(cx + xradius))
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# make sure output coordinates do not exceed image size
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if shape is not None:
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maxr = min(shape[0] - 1, maxr)
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maxc = min(shape[1] - 1, maxc)
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cdef Py_ssize_t r, c
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# output coordinate arrays
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cdef list rr = list()
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cdef list cc = list()
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for r in range(minr, maxr+1):
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for c in range(minc, maxc+1):
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if sqrt(((r - cy) / yradius)**2 + ((c - cx) / xradius)**2) < 1:
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rr.append(r)
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cc.append(c)
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return np.array(rr, dtype=np.intp), np.array(cc, dtype=np.intp)
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def circle(double cy, double cx, double 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 maximum extents 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 extents 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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"""
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return ellipse(cy, cx, radius, radius, shape)
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def circle_perimeter(Py_ssize_t cy, Py_ssize_t cx, Py_ssize_t radius,
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method='bresenham'):
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"""Generate circle perimeter coordinates.
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@@ -373,31 +293,3 @@ def ellipse_perimeter(Py_ssize_t cy, Py_ssize_t cx, Py_ssize_t yradius,
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ychange += twobsquared
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return np.array(py, dtype=np.intp) + cy, np.array(px, dtype=np.intp) + cx
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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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"""
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rr, cc = coords
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rr_inside = np.logical_and(rr >= 0, rr < img.shape[0])
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cc_inside = np.logical_and(cc >= 0, cc < img.shape[1])
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inside = np.logical_and(rr_inside, cc_inside)
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img[rr[inside], cc[inside]] = color
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@@ -0,0 +1,101 @@
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# coding: utf-8
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import numpy as np
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def _coords_inside_image(rr, cc, shape):
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mask = (rr >= 0) & (rr < shape[0]) & (cc >= 0) & (cc < shape[1])
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return rr[mask], cc[mask]
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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 maximum extents 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 extents 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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"""
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dr = 1 / float(yradius)
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dc = 1 / float(xradius)
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r, c = np.ogrid[-1:1:dr, -1:1:dc]
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rr, cc = np.nonzero(r ** 2 + c ** 2 < 1)
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rr.flags.writeable = True
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cc.flags.writeable = True
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rr += cy - yradius
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cc += cx - xradius
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if shape is not None:
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_coords_inside_image(rr, cc, shape)
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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 maximum extents 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 extents 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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"""
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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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"""
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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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