========= pixelscan

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The pixelscan library provides functions to scan pixels on a grid in a variety of spatial patterns. The library consists of scan generators and coordinate transformations. Scan generators are Python generators that return pixel coordinates in a particular spatial pattern. Coordinate transformations are iterators that apply spatial transformations to the coordinates created by the scan generators. Transformation can be chained to yield very generic transformations.

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Documentation

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See the library API documentation here <http://dpmcmlxxvi.github.io/pixelscan>_.

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Usage

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The typical calling syntax is

.. code-block:: python

for x, y in transformation(generator(...), ...): foo(x,y)

For example, the following scans pixels in a clockwise circular pattern from the origin up to a radius of one

.. code-block:: python

for x, y in snap(circlescan(0, 0, 0, 1)): print(x, y)

and will generate the following points

.. code-block:: python

(0,0), (0,1), (1,1), (1,0), (1,-1), (0,-1), (-1,-1), (-1,0), (-1,1)

To skip every other pixel a skip transformation can be applied

.. code-block:: python

for x, y in snap(skip(circlescan(0, 0, 0, 1), step=2)): print(x, y)

which will generate the following points

.. code-block:: python

(0,0), (1,1), (1,-1), (-1,-1), (-1,1)

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Scan Generators

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The following are the currently available generators

+------------------------------------+-----------------------------------------------------------+ | Name | Description | +====================================+===========================================================+ |circlescan |Generates pixels in a clockwise circular pattern | +------------------------------------+-----------------------------------------------------------+ | .. image:: examples/circlescan.png |.. code-block:: python | | | | | | x0, y0, r1, r2 = 0, 0, 0, 2 | | | for x, y in snap(circlescan(x0, y0, r1, r2)): | | | print(x, y) | | | | | |where | | | | | |.. code-block:: rest | | | | | | x0 = Circle x center | | | y0 = Circle y center | | | r1 = Initial radius | | | r2 = Final radius | | | | | |produces the following points: | | | | | |.. code-block:: python | | | | | | ( 0, 0) ( 0, 1) ( 1, 1) ( 1, 0) ( 1,-1) ( 0,-1) | | | (-1,-1) (-1, 0) (-1, 1) ( 0, 2) ( 1, 2) ( 2, 1) | | | ( 2, 0) ( 2,-1) ( 1,-2) ( 0,-2) (-1,-2) (-2,-1) | | | (-2, 0) (-2, 1) (-1, 2) | +------------------------------------+-----------------------------------------------------------+ |gridscan |Generates pixels in rectangular grid pattern | +------------------------------------+-----------------------------------------------------------+ | .. image:: examples/gridscan.png |.. code-block:: python | | | | | | xi, yi, xf, yf = 0, 0, 2, 2 | | | for x, y in gridscan(xi, yi, xf, yf, stepx=1, stepy=1): | | | print(x, y) | | | | | |where | | | | | |.. code-block:: rest | | | | | | xi = Initial x-coordinate | | | yi = Initial y-coordinate | | | xf = Final x-coordinate | | | yf = Final y-coordinate | | | stepx = Step size in x-coordinate | | | stepy = Step size in y-coordinate | | | | | |produces the following points: | | | | | |.. code-block:: python | | | | | | (0,0) (1,0) (2,0) (0,1) (1,1) (2,1) (0,2) (1,2) (2,2) | +------------------------------------+-----------------------------------------------------------+ |hilbertscan |Generates pixels in a Hilbert curve pattern | +------------------------------------+-----------------------------------------------------------+ | .. image:: examples/hilbertscan.png|.. code-block:: python | | | | | | size, distance = 4, 16 | | | for x, y in hilbertscan(size, distance): | | | print(x, y) | | | | | |where | | | | | |.. code-block:: rest | | | | | | size = Size of enclosing square | | | distance = Distance along curve | | | | | |produces the following points: | | | | | |.. code-block:: python | | | | | | (0,0), (0,1), (1,1), (1,0), (2,0), (3,0), (3,1), (2,1) | | | (2,2), (3,2), (3,3), (2,3), (1,3), (1,2), (0,2), (0,3) | +------------------------------------+-----------------------------------------------------------+ |ringscan - chebyshev |Generates pixels in a ring pattern (squares) | +------------------------------------+-----------------------------------------------------------+ | .. image:: examples/chebyshev.png |.. code-block:: python | | | | | | x0, y0, r1, r2 = 0, 0, 0, 2