pixelscan

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.

Usage

The typical calling syntax is

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

For example, the following scans pixels in a counter-clockwise circular pattern from the origin up to a radius of 1

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

and will generate the following points

(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

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

which will generate the following points

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

Scan Generators

The following are the currently available generators

• circlescan

  Generates pixels in a counter-clockwise circular pattern

• gridscan

  Generates pixels in rectangular grid pattern

• randomscan

  Generates pixels in a random pattern within a grid

• ringscan

  Generates pixels in a ring pattern (squares or diamonds)

• snakescan

  Generates pixels by in a snake pattern along the x then y axis

Coordinate Transformations

The following are the currentl available transformations

• reflection

  Reflects the coordinates along the x and/or y axis

• rotation

  Rotates the coordinates about the origin

• sample

  Randomly samples the pixels with a given probability

• scale

  Scales the coordinates with a given scale factors

• skip

  Skips the pixels with the given step size

• snap

  Snap the x and y coordinates to a grid point

• swap

  Swap the x and y coordinates

• translation

  Translates the coordinates by the given offsets

Warnings

Transformations such as the rotation can yield non-grid points. They can be snapped to a grid point using the snap transformation.

Changelog

• v0.1.0

  Initial release