Compile LeapPython and Manipulate protein structure with Leap Motion.

I was interested in Kinect as input device, because Kinect can detect motion as input it feels feature. ;-)
And some days ago, I got new input device “Leap Motion”.
The Leap Motion controller is a small USB peripheral device which is designed to be placed on a physical desktop, facing upward. ( from wiki )
I want to use this device with PyMol!
Let’s try it.
At first to use Leap Motion from python, user need to get Leapmotion SDK. My environment is OSX, so I got SDK v2.3 from developer site.
Installation is little bit complicated for me, because I want to use LeapPython library from virtual environment but the library is linked with native python.
So, I build or change dynamic link following procedure.

In Python2.7, I changed link with following command.

iwatobipen$ cd /somepath/LeapSDK/lib
iwatobipen$ otool -L
	/Library/Frameworks/Python.framework/Versions/2.7/Python (compatibility version 2.7.0, current version 2.7.0)
	@loader_path/libLeap.dylib (compatibility version 0.7.0, current version 2.3.1)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)
	/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 120.0.0)
# change Python link from native to anaconda
iwatobipen$ install_name_tool -change /Library/Frameworks/Python.framework/Versions/2.7/Python /Users/iwatobipen/.pyenv/versions/anaconda-2.4.0/lib/libpython2.7.dylib

In Python3.5, I compiled using swig.
Newest swig will cause error, so I used swig version 3.0.3
I referred following url to do that.
OK Let’s go

# Copy Leap.h, LeapMath.h, Leap.i, and libLeap.dylib into one folder. And type following command.
# Generate LeapPython.cpp withswig -c++ -python -o LeapPython.cpp -interface LeapPython Leap.i
iwatobipen$ swig -c++ -python -o LeapPython.cpp -interface LeapPython Leap.i
# Compile and link 
clang++ -arch x86_64 -I/Users/iwatobipen/.pyenv/versions/anaconda-2.4.0/include/python2.7 LeapPython.cpp libLeap.dylib /Users/iwatobipen/.pyenv/versions/anaconda-2.4.0/lib/libpython2.7.dylib -shared -o

Now I got linked each python version in anaconda.

Unfortunately, I could not install pymol in python3.5. Following code was run in python2.7. I installed pymol by using conda install command.
Pymol Wiki provided sample code to use Leap Motion from pymol. I used the example. I added “path” which placed

import sys
import math
from pymol import cmd
sys.path.insert( 0, '/Users/iwatobipen/develop/py2env/LeapSDK/build/')

import Leap
from Leap import Matrix, Vector

class PymolListener(Leap.Listener):
    def __init__(self, *args, **kwargs):
        super(PymolListener, self).__init__(*args, **kwargs)

        self.prev_frame = None

        self.controller = Leap.Controller()

    def __del__(self):

        super(PymolListener, self).__del__()

    def update_view(self, frame):
        if not self.prev_frame:

        view = list(cmd.get_view())

        if frame.rotation_probability(self.prev_frame) > 0.1:
            m = frame.rotation_matrix(self.prev_frame)
            m *= Matrix(Vector(*view[0:3]),
            view[:9] = m.to_array_3x3()

        if frame.scale_probability(self.prev_frame) > 0.1:
            s = frame.scale_factor(self.prev_frame)
            delta_z = math.log(s) * 100.0
            view[11] += delta_z
            view[15] -= delta_z
            view[16] -= delta_z


    def on_frame(self, controller):
        frame = controller.frame()


        self.prev_frame = frame

listener = PymolListener()

Then run pymol and fetched sample pdb.

iwatobipen$ pymol
# from pymolconsole.
pymol> fetch 1atp
pymol> run

Result is …. It seems work well. Now, I am reading API reference to write code.

Published by iwatobipen

I'm medicinal chemist in mid size of pharmaceutical company. I love chemoinfo, cording, organic synthesis, my family.

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