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About
=====
Pyclipper is a Cython wrapper exposing public functions and classes of
the C++ translation of the `Angus Johnson's Clipper library (ver.
6.4.2) `__.
Pyclipper releases were tested with Python 2.7 and 3.4 on Linux (Ubuntu
14.04, x64) and Windows (8.1, x64).
Source code is available on
[GitHub]. The package is published on
[PyPI].
About Clipper
-------------
Clipper - an open source freeware library for clipping and
offsetting lines and polygons.
The Clipper library performs line & polygon clipping -
intersection, union, difference & exclusive-or, and line &
polygon offsetting. The library is based on Vatti's clipping
algorithm.
\ [Angus Johnson's Clipper
library]\
Install
=======
Dependencies
------------
Cython dependency is optional. Cpp sources generated with Cython are
available in releases.
Note on using the ``setup.py``:
``setup.py operates in 2 modes that are based on the presence of the
dev`` file in the root of the project.
- When dev is **present**, Cython will be used to compile the ``.pyx``
sources. This is the *development mode* (as you get it in the git
repository).
- When dev is **absent**, C/C++ compiler will be used to compile the
``.cpp`` sources (that were prepared in in the development mode).
This is the distribution mode (as you get it on PyPI).
This way the package can be used without or with an incompatible version
of Cython.
The idea comes from [Matt Shannon's bandmat
library].
From PyPI
---------
Cython not required.
::
pip install pyclipper
From source
-----------
Cython required.
Clone the repository:
::
git clone git@github.com:fonttools/pyclipper.git
Install:
::
python setup.py install
After every modification of ``.pyx`` files compile with Cython:
::
python setup.py build_ext --inplace
Clippers' preprocessor directives
---------------------------------
Clipper can be compiled with the following preprocessor directives:
use_int32, use_xyz, use_lines and use_deprecated.
Among these the use_int32 and use_lines can be used with Pyclipper.
- use_int32 - when enabled 32bit ints are used instead of 64bit ints. This
improve performance but coordinate values are limited to the range +/-
46340. In Pyclipper this directive is **disabled** by default.
- use_lines - enables line clipping. Adds a very minor cost to
performance. In Pyclipper this directive is **enabled** by default (since
version 0.9.2b0).
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