Loovelj / swt-python

Fast Stroke Width Transform (SWT) algorithm for use in Python

Fast Stroke Width Transform for Python

This repo contains wrapper for libccv's SWT algorithm for use in Python.

For more information, see my blog post: http://zablo.net/blog/post/stroke-width-transform-swt-python

How to:

1. Checkout libccv (I've forked it at the time when I built this wrapper):

   git clone https://github.com/marrrcin/ccv.git
   

2. Put ccvwrapper.* files from this repo into /lib folder of ccv

3. Use the following script to build the wrapper:

   #!/bin/bash
   swig -python ccvwrapper.i
   
   gcc -fpic -c ccvwrapper.c ccvwrapper_wrap.c ccv_algebra.c ccv_basic.c ccv_cache.c ccv_classic.c ccv_io.c ccv_memory.c ccv_output.c ccv_resample.c ccv_sift.c ccv_swt.c ccv_transform.c ccv_util.c ./3rdparty/sha1/sha1.c -I/usr/include/python2.7
   
   ld -shared ccvwrapper.o ccvwrapper_wrap.o ccv_algebra.o ccv_basic.o ccv_cache.o ccv_classic.o ccv_io.o ccv_memory.o ccv_output.o ccv_resample.o ccv_sift.o ccv_swt.o ccv_transform.o ccv_util.o sha1.o -ljpeg -o _ccvwrapper.so
   
   

4. Copy outputs of the build into your project

   cp ccvwrapper* ~/PycharmProjects/path_to_your_project
   cp _ccvwrapper* ~/PycharmProjects/path_to_your_project
   

5. In Python just use:

   import ccvwrapper
   import numpy as np
   swt_result_raw = ccvwrapper.swt(open("test_input.jpg", "rb").read(), len(bytes), 1024, 1360)
   swt_result = np.reshape(swt_result_raw, (len(swt_result_raw) / 4, 4))
   

6. Done!