The document outlines the structure and components of the ChromeOS UI framework, emphasizing the 'views' and 'aura' systems. It describes how ChromeOS operates as a single X-client application with a unique user interface toolkit designed to provide a differentiated aesthetic. The role of the shell, named 'ash', is highlighted in relation to window management, program execution, and system management within the framework.

1. Views, Aura and Ash:
ChromeOS UI Framework
Simon YoungKi Hong
simonhong@chromium.org

2. About Me
Software Programmer @LGE
(2009.02 ~)
Chromium Contributor
(2012.01 ~)
Chromium Committer
(2013.11 ~)

3. Goal
Overview of ChromeOS UI Component.
We can say
“How ChromeOS UI is constructed!”

4. Goal

5. Background
Chrome? Chromium?

6. ChromeOS
Linux based operating system.
Only chrome browser is running for user.

7. UI Framework
In typical linux,
GUI
Application
GUI
Application
GUI
Application
Window
Manager
gtk
qt
efl
...
X or Wayland
Kernel

8. What kind of ToolKit is used
in ChromeOS?

9. Views
They created UI toolkit called "Views"
"Since we desired a differentiated aesthetic for
Chromium, we have had to build a framework
on Windows to accelerate our development of
custom UI" - Chromium design docs

10. Views
UI is constructed of a tree of view components
Widget
RootView
View
View
View
View
View
View
View

11. Views
Like other toolkits, it has many custom views
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Label
Image view
web view
slider
separator
link
button
combobox
etc...

12. Views

13. OK. we know how Widget is made...
But, who give user events
or draw its content?

14. There is no window manager.
ChromeOS runs single x-client application.
Browser
Process
Renderer
Process
Renderer
Process
libx
X
…...
GPU
Process

15. They created a new window system.
Aura

16. Aura
Chrome's next generation hardware
accelerated UI framework

17. Aura
Contains view components
Responsible for
event propagation
draw widget’s contents
window hierarchy management
- ChromeOS is a tree of Aura Window

18. Aura
Event Flow
Widget component
Aura Window
X
Kernel
Mouse Click

19. Aura
Drawing?
RootWindowHost
CC
RootWindow
Composite
& Draw
Aura
Window
Aura
Window
Aura
Window
Aura
Window
Aura
Window
GPU process
Browser process
GPU

20. OK. we know how Widget is handled...
But, how create a widget?

21. Ash (Aura SHell)
"A shell is software that provides an interface
for users of an operating system to access the
services of a kernel." - wikipedia

22. Ash
In typical linux,
GTK
application
QT
Application
....
X
Kernel
Shell

23. Ash
Role of Shell
* Window mgmt.
* Program exec.
* System mgmt.

24. Ash

25. References
http://dev.chromium.org/developers/design-documents

26. Q&A