draw
Module: draw
skimage.draw.bezier_curve | Generate Bezier curve coordinates. |
skimage.draw.circle (r, c, radius[, shape]) | Generate coordinates of pixels within circle. |
skimage.draw.circle_perimeter | Generate circle perimeter coordinates. |
skimage.draw.circle_perimeter_aa | Generate anti-aliased circle perimeter coordinates. |
skimage.draw.ellipse (r, c, yradius, xradius) | Generate coordinates of pixels within ellipse. |
skimage.draw.ellipse_perimeter | Generate ellipse perimeter coordinates. |
skimage.draw.ellipsoid (a, b, c[, spacing, ...]) | Generates ellipsoid with semimajor axes aligned with grid dimensions on grid with specified spacing . |
skimage.draw.ellipsoid_stats (a, b, c) | Calculates analytical surface area and volume for ellipsoid with semimajor axes aligned with grid dimensions of specified spacing . |
skimage.draw.line | Generate line pixel coordinates. |
skimage.draw.line_aa | Generate anti-aliased line pixel coordinates. |
skimage.draw.polygon | Generate coordinates of pixels within polygon. |
skimage.draw.polygon_perimeter (cr, cc[, ...]) | Generate polygon perimeter coordinates. |
skimage.draw.set_color (img, coords, color[, ...]) | Set pixel color in the image at the given coordinates. |
bezier_curve
-
skimage.draw.bezier_curve()
-
Generate Bezier curve coordinates.
Parameters: y0, x0 : int
Coordinates of the first control point.
y1, x1 : int
Coordinates of the middle control point.
y2, x2 : int
Coordinates of the last control point.
weight : double
Middle control point weight, it describes the line tension.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for curves which exceed the image size. By default the full extent of the curve are used.
Returns: rr, cc : (N,) ndarray of int
Indices of pixels that belong to the Bezier curve. May be used to directly index into an array, e.g.
img[rr, cc] = 1
.Notes
The algorithm is the rational quadratic algorithm presented in reference [R67].
References
[R67] (1, 2) A Rasterizing Algorithm for Drawing Curves, A. Zingl, 2012 http://members.chello.at/easyfilter/Bresenham.pdf Examples
>>> import numpy as np >>> from skimage.draw import bezier_curve >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc = bezier_curve(1, 5, 5, -2, 8, 8, 2) >>> img[rr, cc] = 1 >>> img array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0, 0, 0], [0, 0, 0, 1, 1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 1, 1, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 1, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
circle
-
skimage.draw.circle(r, c, radius, shape=None)
[source] -
Generate coordinates of pixels within circle.
Parameters: r, c : double
Centre coordinate of circle.
radius: double
Radius of circle.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for circles which exceed the image size. By default the full extent of the circle are used.
Returns: rr, cc : ndarray of int
Pixel coordinates of circle. May be used to directly index into an array, e.g.
img[rr, cc] = 1
.Notes
This function is a wrapper for skimage.draw.ellipse()
Examples
>>> from skimage.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)
circle_perimeter
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skimage.draw.circle_perimeter()
-
Generate circle perimeter coordinates.
Parameters: cy, cx : int
Centre coordinate of circle.
radius: int
Radius of circle.
method : {‘bresenham’, ‘andres’}, optional
bresenham : Bresenham method (default) andres : Andres method
shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for circles which exceed the image size. By default the full extent of the circle are used.
Returns: rr, cc : (N,) ndarray of int
Bresenham and Andres’ method: Indices of pixels that belong to the circle perimeter. May be used to directly index into an array, e.g.
img[rr, cc] = 1
.Notes
Andres method presents the advantage that concentric circles create a disc whereas Bresenham can make holes. There is also less distortions when Andres circles are rotated. Bresenham method is also known as midpoint circle algorithm. Anti-aliased circle generator is available with
circle_perimeter_aa
.References
[R68] J.E. Bresenham, “Algorithm for computer control of a digital plotter”, IBM Systems journal, 4 (1965) 25-30. [R69] E. Andres, “Discrete circles, rings and spheres”, Computers & Graphics, 18 (1994) 695-706. Examples
>>> from skimage.draw import circle_perimeter >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc = circle_perimeter(4, 4, 3) >>> img[rr, cc] = 1 >>> img array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 1, 1, 1, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 1, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 1, 0, 0], [0, 1, 0, 0, 0, 0, 0, 1, 0, 0], [0, 1, 0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 1, 0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 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]], dtype=uint8)
circle_perimeter_aa
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skimage.draw.circle_perimeter_aa()
-
Generate anti-aliased circle perimeter coordinates.
Parameters: cy, cx : int
Centre coordinate of circle.
radius: int
Radius of circle.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for circles which exceed the image size. By default the full extent of the circle are used.
Returns: rr, cc, val : (N,) ndarray (int, int, float)
Indices of pixels (
rr
,cc
) and intensity values (val
).img[rr, cc] = val
.Notes
Wu’s method draws anti-aliased circle. This implementation doesn’t use lookup table optimization.
References
[R70] X. Wu, “An efficient antialiasing technique”, In ACM SIGGRAPH Computer Graphics, 25 (1991) 143-152. Examples
>>> from skimage.draw import circle_perimeter_aa >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc, val = circle_perimeter_aa(4, 4, 3) >>> img[rr, cc] = val * 255 >>> img array([[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [ 0, 0, 60, 211, 255, 211, 60, 0, 0, 0], [ 0, 60, 194, 43, 0, 43, 194, 60, 0, 0], [ 0, 211, 43, 0, 0, 0, 43, 211, 0, 0], [ 0, 255, 0, 0, 0, 0, 0, 255, 0, 0], [ 0, 211, 43, 0, 0, 0, 43, 211, 0, 0], [ 0, 60, 194, 43, 0, 43, 194, 60, 0, 0], [ 0, 0, 60, 211, 255, 211, 60, 0, 0, 0], [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
ellipse
-
skimage.draw.ellipse(r, c, yradius, xradius, shape=None)
[source] -
Generate coordinates of pixels within ellipse.
Parameters: r, c : double
Centre coordinate of ellipse.
yradius, xradius : double
Minor and major semi-axes.
(x/xradius)**2 + (y/yradius)**2 = 1
.shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for ellipses which exceed the image size. By default the full extent of the ellipse are used.
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
.Examples
>>> from skimage.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)
ellipse_perimeter
-
skimage.draw.ellipse_perimeter()
-
Generate ellipse perimeter coordinates.
Parameters: cy, cx : int
Centre coordinate of ellipse.
yradius, xradius : int
Minor and major semi-axes.
(x/xradius)**2 + (y/yradius)**2 = 1
.orientation : double, optional (default 0)
Major axis orientation in clockwise direction as radians.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for ellipses which exceed the image size. By default the full extent of the ellipse are used.
Returns: rr, cc : (N,) ndarray of int
Indices of pixels that belong to the ellipse perimeter. May be used to directly index into an array, e.g.
img[rr, cc] = 1
.References
[R71] A Rasterizing Algorithm for Drawing Curves, A. Zingl, 2012 http://members.chello.at/easyfilter/Bresenham.pdf Examples
>>> from skimage.draw import ellipse_perimeter >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc = ellipse_perimeter(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, 1, 1, 1, 1, 1, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 1, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 1], [0, 1, 0, 0, 0, 0, 0, 0, 0, 1], [0, 1, 0, 0, 0, 0, 0, 0, 0, 1], [0, 0, 1, 0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 1, 1, 1, 1, 1, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
ellipsoid
-
skimage.draw.ellipsoid(a, b, c, spacing=(1.0, 1.0, 1.0), levelset=False)
[source] -
Generates ellipsoid with semimajor axes aligned with grid dimensions on grid with specified
spacing
.Parameters: a : float
Length of semimajor axis aligned with x-axis.
b : float
Length of semimajor axis aligned with y-axis.
c : float
Length of semimajor axis aligned with z-axis.
spacing : tuple of floats, length 3
Spacing in (x, y, z) spatial dimensions.
levelset : bool
If True, returns the level set for this ellipsoid (signed level set about zero, with positive denoting interior) as np.float64. False returns a binarized version of said level set.
Returns: ellip : (N, M, P) array
Ellipsoid centered in a correctly sized array for given
spacing
. Boolean dtype unlesslevelset=True
, in which case a float array is returned with the level set above 0.0 representing the ellipsoid.
ellipsoid_stats
-
skimage.draw.ellipsoid_stats(a, b, c)
[source] -
Calculates analytical surface area and volume for ellipsoid with semimajor axes aligned with grid dimensions of specified
spacing
.Parameters: a : float
Length of semimajor axis aligned with x-axis.
b : float
Length of semimajor axis aligned with y-axis.
c : float
Length of semimajor axis aligned with z-axis.
Returns: vol : float
Calculated volume of ellipsoid.
surf : float
Calculated surface area of ellipsoid.
line
-
skimage.draw.line()
-
Generate line pixel coordinates.
Parameters: y0, x0 : int
Starting position (row, column).
y1, x1 : int
End position (row, column).
Returns: rr, cc : (N,) ndarray of int
Indices of pixels that belong to the line. May be used to directly index into an array, e.g.
img[rr, cc] = 1
.See also
-
line_aa
- Anti-aliased line generator
Examples
>>> from skimage.draw import line >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc = line(1, 1, 8, 8) >>> img[rr, cc] = 1 >>> img array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
-
line_aa
-
skimage.draw.line_aa()
-
Generate anti-aliased line pixel coordinates.
Parameters: y0, x0 : int
Starting position (row, column).
y1, x1 : int
End position (row, column).
Returns: rr, cc, val : (N,) ndarray (int, int, float)
Indices of pixels (
rr
,cc
) and intensity values (val
).img[rr, cc] = val
.References
[R72] A Rasterizing Algorithm for Drawing Curves, A. Zingl, 2012 http://members.chello.at/easyfilter/Bresenham.pdf Examples
>>> from skimage.draw import line_aa >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc, val = line_aa(1, 1, 8, 8) >>> img[rr, cc] = val * 255 >>> img array([[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [ 0, 255, 56, 0, 0, 0, 0, 0, 0, 0], [ 0, 56, 255, 56, 0, 0, 0, 0, 0, 0], [ 0, 0, 56, 255, 56, 0, 0, 0, 0, 0], [ 0, 0, 0, 56, 255, 56, 0, 0, 0, 0], [ 0, 0, 0, 0, 56, 255, 56, 0, 0, 0], [ 0, 0, 0, 0, 0, 56, 255, 56, 0, 0], [ 0, 0, 0, 0, 0, 0, 56, 255, 56, 0], [ 0, 0, 0, 0, 0, 0, 0, 56, 255, 0], [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
polygon
-
skimage.draw.polygon()
-
Generate coordinates of pixels within polygon.
Parameters: y : (N,) ndarray
Y-coordinates of vertices of polygon.
x : (N,) ndarray
X-coordinates of vertices of polygon.
shape : tuple, optional
Image shape which is used to determine the maximum extent of output pixel coordinates. This is useful for polygons which exceed the image size. By default the full extent of the polygon are used.
Returns: rr, cc : ndarray of int
Pixel coordinates of polygon. May be used to directly index into an array, e.g.
img[rr, cc] = 1
.Examples
>>> from skimage.draw import polygon >>> img = np.zeros((10, 10), dtype=np.uint8) >>> x = np.array([1, 7, 4, 1]) >>> y = np.array([1, 2, 8, 1]) >>> rr, cc = polygon(y, x) >>> 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, 1, 1, 1, 1, 1, 0, 0, 0], [0, 0, 1, 1, 1, 1, 1, 0, 0, 0], [0, 0, 0, 1, 1, 1, 0, 0, 0, 0], [0, 0, 0, 1, 1, 1, 0, 0, 0, 0], [0, 0, 0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 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]], dtype=uint8)
polygon_perimeter
-
skimage.draw.polygon_perimeter(cr, cc, shape=None, clip=False)
[source] -
Generate polygon perimeter coordinates.
Parameters: cr : (N,) ndarray
Row (Y) coordinates of vertices of polygon.
cc : (N,) ndarray
Column (X) coordinates of vertices of polygon.
shape : tuple, optional
Image shape which is used to determine maximum extents of output pixel coordinates. This is useful for polygons which exceed the image size. By default the full extents of the polygon are used.
clip : bool, optional
Whether to clip the polygon to the provided shape. If this is set to True, the drawn figure will always be a closed polygon with all edges visible.
Returns: pr, pc : ndarray of int
Pixel coordinates of polygon. May be used to directly index into an array, e.g.
img[pr, pc] = 1
.Examples
>>> from skimage.draw import polygon_perimeter >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc = polygon_perimeter([5, -1, 5, 10], ... [-1, 5, 11, 5], ... shape=img.shape, clip=True) >>> img[rr, cc] = 1 >>> img array([[0, 0, 0, 0, 1, 1, 1, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0, 1, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 1, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 1], [1, 0, 0, 0, 0, 0, 0, 0, 0, 1], [1, 0, 0, 0, 0, 0, 0, 0, 0, 1], [1, 0, 0, 0, 0, 0, 0, 0, 0, 1], [0, 1, 1, 0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 1, 0, 0, 0, 1, 1, 0], [0, 0, 0, 0, 1, 1, 1, 0, 0, 0]], dtype=uint8)
set_color
-
skimage.draw.set_color(img, coords, color, alpha=1)
[source] -
Set pixel color in the image at the given coordinates.
Coordinates that exceed the shape of the image will be ignored.
Parameters: img : (M, N, D) ndarray
Image
coords : tuple of ((P,) ndarray, (P,) ndarray)
Row and column coordinates of pixels to be colored.
color : (D,) ndarray
Color to be assigned to coordinates in the image.
alpha : scalar or (N,) ndarray
Alpha values used to blend color with image. 0 is transparent, 1 is opaque.
Returns: img : (M, N, D) ndarray
The updated image.
Examples
>>> from skimage.draw import line, set_color >>> img = np.zeros((10, 10), dtype=np.uint8) >>> rr, cc = line(1, 1, 20, 20) >>> set_color(img, (rr, cc), 1) >>> img array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 1]], dtype=uint8)
© 2011 the scikit-image team
Licensed under the BSD 3-clause License.
http://scikit-image.org/docs/0.12.x/api/skimage.draw.html