Tutorial

Here is a simple example using pypotrace:

import potrace

# Make a numpy array with a rectangle in the middle
data = np.zeros((32, 32), np.uint32)
data[8:32-8, 8:32-8] = 1

# Create a bitmap from the array
bmp = potrace.Bitmap(data)

# Trace the bitmap to a path
path = bmp.trace()

# Iterate over path curves
for curve in path:
    print "start_point =", curve.start_point
    for segment in curve:
        print segment
        end_point_x, end_point_y = segment.end_point
        if segment.is_corner:
            c_x, c_y = segment.c
        else:
            c1_x, c1_y = segment.c1
            c2_x, c2_y = segment.c2

The main class is Bitmap. You pass its constructor a 2D numpy array, and you call its trace() method to convert it to a Path object.