.. _dev_guide:

Quick Start Guide for developers
================================

NEFI2 is built with `MVC pattern <https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller>`_, so you will find familiar directories like "model" and "view" (we removed "controller" in latest versions) inside the project repository.

There are 3 main components in NEFI2 that you need to know about: **Pipeline**, **Categories** and **Algorithms**.
**Pipeline** contains **Categories** which in turn contain **Algorithms**.
**Category** is a collection of algorithms that fulfill specific image processing task.

Basically, the most important files you need to know are:

::

  model/pipeline.py
  model/ext_loader.py
  view/controller.py
  view/MainView.ui

| **pipeline.py** --> controls application data flow, reading and writing any data to disk.
| **ext_loader.py** --> looks through available algorithms and categories and instantiates them at startup.
| **controller.py** --> contains various UI controllers and methods are here.
| **MainView.ui** --> a UI template created in QTDesigner.
|

NEFI2 Architechture
+++++++++++++++++++

.. figure::  images/nefi2.png
   :align:   center
   :scale: 85%

The core of NEFI2 is the **Pipeline** class which controls how data is processed.
Whenever an algorithm produces a result, the **Pipeline** passes the result to the next **Algorithm** in a queue.
Intermediate results are saved on disk.

NEFI2 Startup
+++++++++++++

.. figure::  images/pipeline_start.png
   :align:   center
   :scale: 85%

The idea behind **Extension Loader** class which resides in ``ext_loader.py`` is to search and instantiate **Categories** during startup.
The **Categories**, in turn, will instantiate all **Algorithms** (each category instantiates only the algorithms that belong to it). Once the **Algorithms** are instantiated controller creates the necessary widgets for **Algorithm** settings in the UI.

This is it so far, if you wanna dig further, continue to read the :ref:`codebase`.

Keep in mind that this project is in its early stages and even though we tried our best it has bugs, so don't be shy add report bugs on our `Github page <http://www.github.com/???`_.