====== Using the Python API on Linux ======
====== 1.0. Introduction ======

Pixy2 now has a Python wrapper for libpixyusb2. For now, this is only available for Linux-based controllers (e.g. Raspberry Pi, BeagleBone). The [[wiki:v2:building_the_libpixyusb_example_on_linux|libpixyusb2]] library provides a software application programming interface (API) for communicating with Pixy2 over USB. The following procedure will outline the steps to build libpixyusb2 as a Python module.

This procedure assumes the following:

* Your system has Linux Mint installed
* Your system is connected to the internet

Although this procedure uses Linux Mint, it should work with any Linux distribution that uses the Debian package manager (e.g. Ubuntu).

====== 2.0. Procedure ======
===== 2.1. Install dependencies for building Python SWIG module ======
Start a terminal application. In the terminal window type:

''%%# sudo apt-get install swig libusb-1.0-0-dev g++ git%%''

===== 2.2. Download Pixy2 source code =====

In the terminal window type:

''%%# git clone https://github.com/charmedlabs/pixy2 %%''

===== 2.3. Build the Pixy2 SWIG module =====

In the terminal window type:

''%%# cd pixy2/scripts%%''\\
''%%# ./build_python_demos.sh%%''

===== 2.4. Try it out! =====

Change directory to the build folder. In your terminal window type:

''%%# cd ../build/python_demos%%''

==== 2.4.1. Run the get blocks demo ====
Make sure your Pixy2 is connected to a USB port on your computer. Then in a terminal window type:

''%%# python get_blocks_python_demo.py%%''

If all goes well you should see blocks:

''%%Pixy2 Python SWIG Example -- Get Blocks%%''\\
''%%frame   0:%%''\\
''%%[BLOCK: SIG=1 X=157 Y=103 WIDTH=314 HEIGHT=207]%%''\\
''%%frame   1:%%''\\
''%%[BLOCK: SIG=1 X=157 Y=103 WIDTH=314 HEIGHT=207]%%''\\
''%%frame   2:%%''\\
''%%[BLOCK: SIG=1 X=157 Y=103 WIDTH=314 HEIGHT=207]%%''\\
''%%frame   3:%%''\\
''%%[BLOCK: SIG=1 X=157 Y=103 WIDTH=314 HEIGHT=207]%%''\\

If you don't see any block information, try running as superuser:

''%%# sudo python get_blocks_python_demo.py%%''

==== 2.4.2. Run the get lines demo ====
Make sure your Pixy2 is connected to a USB port on your computer. Then in a terminal window type:

''%%# python get_lines_python_demo.py%%''

Example output:

''%%Pixy2 Python SWIG Example -- Get Line Features%%''\\
''%%frame   0:%%''\\
''%%[VECTOR: INDEX=1 X0= 50 Y0= 15 X1= 50 Y1=  5]%%''\\
''%%[VECTOR: INDEX=2 X0= 56 Y0=  8 X1= 67 Y1=  4]%%''\\
''%%frame   1:%%''\\
''%%[VECTOR: INDEX=0 X0= 55 Y0= 27 X1= 51 Y1=  2]%%''\\
''%%frame   2:%%''\\
''%%[VECTOR: INDEX=0 X0= 55 Y0= 27 X1= 51 Y1=  2]%%''\\
''%%frame   3:%%''\\
''%%[VECTOR: INDEX=1 X0= 57 Y0= 31 X1= 53 Y1= 21]%%''

If you don't see any line feature information, try running as superuser:

''%%# sudo python get_lines_python_demo.py%%''