Enlightenment Foundation Libraries (Overview)

1Samsung Open Source Group

Cedric BailSenior Graphics Developer

Samsung Open Source Group [email protected]

Enlightenment Foundation Libraries

An UI Toolkit Designed for the Embedded World

mailto:[email protected]


● What are the Enlightenment Foundation Libraries?

● Where are they used?

● Where it is going?

● Questions?


What is EFL?


EFL: A Toolkit Created for Enlightenment 17


Enlightenment 17

– Enlightenment project started in 1997

– Windows Manager

– First Windows Manager of GNOME

– Full rewrite started in 2001

– Primary belief is there will never be “a year of the Linux desktop”

– Designed with the embedded world in mind…

– … and needed a toolkit !


Enlightenment

– 17 was just the version number, we are now at 19!

– Use EFL scenegraph and main loop

– Not different from any other EFL application

– Composite and Window Manager

– Wayland client support

– Multiple backend (X, FB, DRM, …)

– Highly customizable (Profiles, modules and themes)


Enlightenment Community

● The Enlightenment community

– 60 uniq contributors per release (10 cores)

– 1000 users that build from source

– 2 distributions based on Enlightenment (Bodhi and Elive)

● The Enlightenment community expected Linux to takeoff in the embedded world, not on the desktop

● The values shared by this community:

● Customizable● Scalable

● Fast● Light● Feature Rich


Enlightenment Foundation Libraries (EFL)

● Spent a decade writing a modern graphic toolkit

● Licensed under a mix of LGPL and BSD license

● Focus on embedded devices

● First release on January 2011

● Stable, long term API/ABI

● In the process of releasing version 1.13

● 3 month release cycle


State of EFL

● Designed for creating a Windows Manager (WM), now used for any type of

application

● Has its own scene graph and rendering library

● Optimized to reduce CPU, GPU, memory and battery usage

● Supports international language requirements (LTR/RTL, UTF8)

● Supports all variations of screens and input devices (scale factor)

● Fully Themable (layout of the application included)

● Supports profiles

● Can take up as little as 8MB of space with a minimal set of dependencies

● Has a modular design


Why We Care About Optimization

● Moore's law doesn't apply to battery and memory bandwidth

● Most rendering operations are limited directly by memory bandwidth

● Many embedded devices have less available memory than a low end phone

– Refrigerator, oven, dish washer, washing machine, home automation…

● Even a low end phone doesn't have much memory to space once you run a browser!

● GL context at best consumes 10MB, usually more around 40MB; this is bad

for multitasking!


Current State of Optimization

● Application runtime memory use is mostly driven by screen size

● EFL can fit in 8MB on disk (static compilation with minimal dependencies)

● No hard requirement on the GPU

● Enlightenment + Arch Linux combined :

– 48 MB RAM

– 300 Mhz (1024 x 768)

– Yes, for a desktop profile!


Under the Hood


Bird's Eye View of EFL

X11

OpenGL

EINAMEMPOOL

EVAS

JPEG

PNG

GIF

TIFF

EET

SVG

MORE...

XRENDER

OPENGL/ES

X11 (SOFTWARE)

FB (SOFTWARE)

MORE...

EET

EMBRYO

EDJE

ELEMENTARY E-DBUS DBUS

ECOREFILE

X11

CON

IPC

FB

EVAS

QUARTZ

INPUT

JOB

SDL

WIN32/CE

MORE...

EFREET

MEMORY (RAM) (DATA STRUCTURES)

DATA IN STORAGE (DISK/FLASH ETC.)

PIXELS ON A DISPLAY

IMAGE FILES IN STORAGE

OTHER APPLICATIONS AND SERVICES

USER INTERACTION AND FEEDBACK

INPUT DEVICES AND OTHER SYSTEM SERVICES AND COMPONENTS

ABSTRACTED UI COMPONENTS FROM STORAGE

FREEDESKTOP.ORG STANDARDS LAYER

FAST VIRTUAL MACHINE FOR LOGIC AUGMENTATION


EET: Serialization of C Structure

● Something very specific to EFL

● Fast serialization library for file storage and network communication

● Store image, sounds, font

● Reduces overhead when loading the same data across multiple applications

● Provides tools to convert from and to a human readable form

● Configurations and themes are built with this library


Evas: Scene Graph Canvas

● The brain of EFL

● Has its own scene graph and rendering library with more than 10 years of optimization work

● Provides glitch-free rendering

● Reduces overdrawing

● Deduplicates as much as possible to reduce memory waste

● Offers compressed glyph rendering

● Is portable (SDL, X11, Wayland, FB, DRM, Windows, Mac OS X, ...)

● Has an optimized software renderer (MMX, SSE*, Neon)

● Optimized use of GPU (optional)

– Supports partial updates (assuming the driver does)

– Reduces context and texture switches as much as possible

– Reduces memory overhead


Scene Graph

Container

Container Container

Container Container

Example scene graph


Evas: Scene Graph

● A basic scene graph rendering ascends from the bottom to the top of the tree

● Possible optimizations

– Reorder GL operations to limit Texture and Shader changes

– Partial updates

– Cutout opaque areas

– Complete drawing operations in another thread

– Efficiently cache costly CPU operations between frames

– Deduplicate objects


Evas: Frame Delta

Computation of previous and current frame with cutout


Evas: Rendering Pipeline

Current and future rendering pipeline for Evas


Evas: Learned Experience From Our Scene Graph

● After initial startup... it's mostly bound to the memory

● Vector graphics and smooth scaled images are bound to the CPU

● It's important to optimize memory usage for both GL and software

● Deduplication of strings, images and text makes a major difference

● The compressed glyph (software) and image (GL) also make a difference


Evas: Issue With Design of Future Pipeline

● CPU and memory frequency are very important

● Evas was created when dual core CPU's were found only on high end servers

● It's slowly evolving to take advantage of more cores

● The Linux Kernel handles it poorly on embedded devices

● Typical scenario :

1. Long periods of IO bound operations (Main loop)

2. Followed by a short need for all cores to be up and running

3. Processes are then limited by memory speed

● In this scenario, it's not capable of running at the right speed with the right number of cores

● A lot of work is needed in the kernel before we can totally benefit from it


Edje: Theme and Layout Engine

● The heart of EFL

● Theme and layout engine

● Descriptive language

● Uses Evas for rendering logic (fully independent from the system)

● Doesn't require a FPU

● Optimizes load time (time to first frame) and run time

● Reduces memory fragmentation


Edje in Action


Elementary: Widgets Set

● Widgets toolkit

● Based on EFL infrastructure, uses Edje & Evas

● Screen and input independence achieved through :

– Scale factor

– Finger size

● Profile support (define configuration on a per Window basis)

● Fully themable

● Supports touchscreens


Many Other Useful Components

● Eina: C data types library and various system helper

● Ecore: main loop, events, network and threads infrastructure

● Eio: asynchronous Input/Output

● Emotion: video component integration

● Eeze: hot plug and device detection

● Eldbus: dbus integration library

● Efreet: Freedesktop library

● Eo: safe, fast and light object infrastructure

● Eolian: compilation time introspection infrastructure

● Elocation: geoclue integration


Bindings for all Sorts of Languages

● C++11 modern binding (RAII, lambda, …)

● Lua

● Python

● JS

● Ocaml (see http://win-builds.org)

http://win-builds.org/


Where is EFL Used?


First Tizen Device: Camera

Samsung NX300


Smart Watch: Gear Series

Samsung Gear 2 Samsung Gear S


Smart Phone: Z1

Samsung Z1


Smart TV

Samsung TV


Many Other Products

● Fridge

● Printer

● Medical device

● Set top box

● Home automation

● Navigation system

● More to come...


Where is EFL Going?


Improving Performance

● Faster, lighter, better

● Better support for systems without MMU

● Improve speed of software renderer (more colorspace support)

● Slowly roll in threads for CPU intensive tasks

● Improve speed of GPU renderer (more efficient packing)

● Speed up animation filter (Dedicated assembler and shader)

● Efficiently share data across processes

● Experiment with new memory layouts for Eo object


Improve Functionality

● Improve 3D scene graph inside Evas canvas (3D world, Effect, …)

● Add SVG scene graph and Vector graphics API in Evas

● Animated filters

● Improve portability (Windows, Mac OS X)

● Keep it always up to date (C++, Lua, Python, JS, Ocaml)

● Improve tests and automatic build system to improve quality

● Improve documentation


Animated Filter !

Animated bump map filter effect on an image


3D Scene Graph

Example of using current Evas 3D scene graph


The Future of Enlightenment

● X11 will be made optional by serving as a KMS/DRM Wayland Compositor

● Incorporate Elementary widgets set

● Differentiate from Qt logic to provide a library to do your own compositor→ Enlightenment is the base to put your module in for your specific needs

● Improve support for HiDPI

● Improve modularity

● Support more upstream profiles (Tiling, mobile, TV, ...)


EFL Cheat Sheet

● Fast release cycle: 3 months

● Used in Tizen

● Will always support systems with no GPU and limited resources

● Continuous EFL benchmarking to make sure that each release improves on the last

● Majority is licensed under LGPL

● Backend is covered under MIT license

● World wide community


Questions?

Twitter: @SamsungOSGEmail: [email protected]

Slides: http://www.slideshare.net/SamsungOSG

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Enlightenment Foundation Libraries (Overview)

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