potrace Python bindings

These bindings provide an object oriented API to the potrace_ library.

The full API documentation is on <https://pythonhosted.org/pypotrace/>_.

Example usage

The bindings work with input images represented as numpy arrays::

import numpy as np
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

Installation

Ubuntu

Install system dependencies::

    $ sudo apt-get install build-essential python-dev libagg-dev libpotrace-dev pkg-config

Install pypotrace::

    $ git clone https://github.com/flupke/pypotrace.git
    $ cd pypotrace
    $ pip install numpy
    $ pip install .

CentOS/RedHat

Install system dependencies::

$ sudo yum -y groupinstall "Development Tools"
$ sudo yum -y install agg-devel potrace-devel python-devel

Install pypotrace::

$ git clone https://github.com/flupke/pypotrace.git
$ cd pypotrace
$ pip install numpy
$ pip install .

OSX

Install system dependencies::

    $ brew install libagg pkg-config potrace

Install pypotrace::

    $ git clone https://github.com/flupke/pypotrace.git
    $ cd pypotrace
    $ pip install numpy
    $ pip install .

Windows

Thanks to klonuo <https://github.com/klonuo>_ for the instructions

Here are instruction how to make this package work on Windows, by using MinGW system. Probably it can be done with Visual Studio, but I lack skills to make such magic.

So assuming user has MinGW available, additional two packages are needed:

1. potrace source: http://potrace.sourceforge.net/#downloading
2. agg source: http://www.antigrain.com/download/index.html

I extracted both packages in my C:\src folder. Both are easy to build by executing ./configure; make and ./autogen.sh; make respectively, on MSYS prompt.

After that, we need some variables to build pypotrace successfully:

First, includes paths:

• "numpy/arrayobject.h": C:/Python27/Lib/site-packages/numpy/core/include
• potrace headers: C:/src/potrace-1.11/src
• agg headers: C:/src/agg-2.5

there is a little catch for agg includes, as paths referenced in cpp sources point to agg2/*.h while in downloaded agg package we don't have agg2 folder. For me it was easiest to rename C:/src/agg-2.5/include to C:/src/agg-2.5/agg2 and use C:/src/agg-2.5 as agg include folder.

Next, libdirs for libraries we build above:

• potrace: C:/src/potrace-1.11/src/.libs
• agg: C:/src/agg-2.5/src

and we can make pypotrace build command, and execute it::

python setup.py build_ext -IC:/Python27/Lib/site-packages/numpy/core/include;C:/src/potrace-1.11/src;C:/src/agg-2.5 -LC:/src/potrace-1.11/src/.libs;C:/src/agg-2.5/src

Finally install the package::

C:\src\git\pypotrace>python setup.py install
running install
running build
running build_py
copying potrace\__init__.py -> build\lib.win32-2.7\potrace
copying potrace\agg\__init__.py -> build\lib.win32-2.7\potrace\agg
running build_ext
skipping 'potrace\_potrace.c' Cython extension (up-to-date)
skipping 'potrace\bezier.cpp' Cython extension (up-to-date)
skipping 'potrace/agg\curves.cpp' Cython extension (up-to-date)
running install_lib
creating C:\Python27\Lib\site-packages\potrace
creating C:\Python27\Lib\site-packages\potrace\agg
copying build\lib.win32-2.7\potrace\agg\curves.pyd -> C:\Python27\Lib\site-packages\potrace\agg
copying build\lib.win32-2.7\potrace\agg\__init__.py -> C:\Python27\Lib\site-packages\potrace\agg
copying build\lib.win32-2.7\potrace\bezier.pyd -> C:\Python27\Lib\site-packages\potrace
copying build\lib.win32-2.7\potrace\_potrace.pyd -> C:\Python27\Lib\site-packages\potrace
copying build\lib.win32-2.7\potrace\__init__.py -> C:\Python27\Lib\site-packages\potrace
byte-compiling C:\Python27\Lib\site-packages\potrace\agg\__init__.py to __init__.pyc
byte-compiling C:\Python27\Lib\site-packages\potrace\__init__.py to __init__.pyc
running install_egg_info
Writing C:\Python27\Lib\site-packages\pypotrace-0.1-py2.7.egg-info

Running tests

You can check everything is working correctly by running the tests::

$ pip install '.[dev]'
$ nosetests -v

Documentation

The documentation is hosted here: http://packages.python.org/pypotrace

A copy is also included in the doc/_build/html directory of the source distribution.

Homepage

This project is hosted on github: http://github.com/flupke/pypotrace

.. _potrace: http://potrace.sourceforge.net/