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~~Title: About EFL~~
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# EFL #

![EFL Core](/_media/efl-core.png)

EFL, or the *Enlightenment Foundation Libraries*, powers millions of systems from mobile phones to set-top boxes, desktops, laptops, game systems and more. EFL is recognized for its forward-thinking approach, which allows product designers and developers to offer more than the run-of-the-mill user experience of the past. This is where EFL excels.

[Free.fr](http://www.free.fr) has shipped millions of set top boxes in France powered by EFL. The [Openmoko Freerunner project](http://wiki.openmoko.org/wiki/Neo_FreeRunner) also sold thousands of devices using EFL and Enlightenment.

EFL powers [Samsung Galaxy Watch](http://www.samsung.com/us/mobile/wearable-tech) smartwatches and is behind Samsung Smart Televisions such as the [Class Q9F QLED 4K TV](https://www.samsung.com/us/televisions-home-theater/tvs/qled-tvs/65--class-q9f-qled-4k-tv-qn65q9famfxza/) and refrigerators such as the [Samsung Family Hub Refrigerator](https://www.samsung.com/us/explore/family-hub-refrigerator/overview/), which are based on Tizen. GPS devices such as the [Coyote](https://www.moncoyote.com/) also run EFL.

You can [download EFL from here](/download).

## How to Use EFL ##

EFL covers a wide range of functions, including graphics, user interfaces, inter-process communication (IPC), audio and even location services. Other powerful features include file handling utilities, thumbnailing and rendering via scene graph.

## Parts of EFL ###

EFL is made up of a number of libraries which build on top of each other in layers, steadily becoming higher-level, yet allowing access to each level as they go. The higher up you go, the less you have to do yourself. Out widget toolkit is about as high up as you get, while you can still access layers below it for greater control or lower level tasks.

EFL is written in C and exposes all of its APIs by default in C. Binding support exists for several languages, including Python, C++ and Lua. As the object based Unified API is completed more language bindings will become available.

The main focus is on C mostly because the underlying libraries have been around for a long time, were originally written in that language, and the developers of those libraries prefer C. Moving from C would also limit the audience. C programmers couldn't access a C++ API for instance, whereas a C++ programmer can access both C and C++. The developers aim to have bindings auto-generate so programmers of various languages can get native-like APIs for their chosen language from the same core EFL API set.

Efl is currently undergoing a transition from our current stable module-based presentation where each area has its own name to a unified structure all under the Efl namespace.

### Unified EFL ###

The Unified Efl API is split into three main areas: Efl_Core, Efl_Net and Efl_Ui, each encompassing the one before so you can include a single reference in your app. For basic offline applications use Efl_Core, for additional network and connectivity use Efl_Net and if you are building a graphical application then use Efl_Ui (the widget toolkit).

| Component | Description |
| --------- | ----------- |
| Efl_Core  | Structures and functions for application runtime and object lifecycle including mainloop, I/O and events |
| Efl_Net   | Network access and session management including helpers for HTTP etc |
| Efl_Ui    | Full graphical features including scene graph rendering, 3D and widget toolkit |

### Stable (module based) API ###

The stable EFL API components are divided into named modules. Core EFL components include:

| Component | Description |
| --------- | ----------- |
| Evas | Core scene graph and rendering |
| Eina | Data structures and low level helpers |
| Edje | UI layout & animation data files for themes |
| Eet | Data (de)serialization and storage  |
| Ecore | Core loop and system abstractions like X11 |
| Efreet | Freedesktop.org standards handling  |
| Eldbus | D-Bus glue and handling   |
| Embryo | Tiny VM and compiler based on Pawn  |
| Eeze | Device enumeration and access library  |
| Emotion | Video decode wrapping, glue and abstraction |
| Ethumb | Thumbnailing handler  |
| Ephysics | Physics (bullet) wrapper and Evas glue  |
| EIO | Asynchronous I/O handling  |
| Evas Generic Loaders | Extra image loaders for complex image types|
| Emotion Generic Players | Extra video decoders (for VLC)      |
| Elementary | Widgets and high-level abstractions    |

### The EFL Model ###

![model1](/_media/model1.png "EFL Model")

EFL operates on the same "main loop" concept adopted by GTK+ and many other toolkits. Once you initialize an application, it enters the Ecore main loop.

The main loop continuously checks for events, handles timers, callbacks and any other services that have previously been set up until an exit request is sent. By way of an example if EFL were used to create a video game, the mainloop would check for user inputs and update the game world accordingly as you play.

The mainloop is designed efficiently. It will remain idle, consuming virtually no CPU resources until an event occurs. Events can be based on user input, such as using the mouse or time-based. Ecore will then handle the event appropriately.

Read more about [the Ecore main loop here](https://docs.enlightenment.org/auto/group__Ecore__Main__Loop__Group.html).

For more detailed information on the EFL model including events and callbacks see the [EFL Concept Overview.](https://phab.enlightenment.org/w/efl_concept_overview/)

### EFL Application Structure ###

![model1](/_media/efllibs.png "EFL Libs")

Whenever you create a basic EFL Application, it uses a basic set of libraries:

  * **Elementary** is the top-most library. It provides all the functions you need to create windows, manage layouts, and add widgets.
  * **Edje**  is the library used by Elementary to provide powerful, customisable themes. You can also use Edje to create your own objects and use them in an application.
  * **Ecore** is the library that manages the main loop of your application, as outlined above.
  * **Evas**  is the canvas engine that draws content. Any graphical objects you create are Evas objects. It handles the entire state of the window by filling the canvas with objects and manipulating their states. Evas objects are created and then manipulated until they are no longer needed, at which point they are deleted.
  * **Eina** forms the basis of all EFL libraries. It's a toolbox that implements an API for data types in an efficient way. Eina contains all the functions needed to create lists and hashes, manage shared strings, open shared libraries, and manage errors and memory pools.

EFL naturally contains many more libraries than the basic ones outlined above. Visit our [Basic Application Structure](https://www.enlightenment.org/develop/legacy/program_guide/basic_application_structure_pg) page for more information on the core libraries. You can also learn about other libraries in our other programming guides.

## Further Reading ##

[EFL Coverity scan status](https://scan.coverity.com/projects/552)
:    EFL's code quality.

[Ecore loop](https://docs.enlightenment.org/auto/group__Ecore__Main__Loop__Group.html)
:    Functions that act on Ecore's main loop or on events and infrastructure directly linked to it.

[EFL Concept Overview.](https://phab.enlightenment.org/w/efl_concept_overview/)
:    More detailed information on the EFL model including events and callbacks