On Monday, 27 de December de 2010 15:01:55 john pratss wrote: > Hi all, > why is qt embedded not being used as part of UI development framework and > why is qt X11 is being used instead???
For two main reasons:
1) inside Qt: Qt for Embedded Linux is an older codebase, with a lot of hacks,
created for a class of embedded devices with very, very limited capabilities.
This class of devices is disappearing and MeeGo is definitely not targetting
them: MeeGo targets the high-end, where memory and graphics capabilities
aren't that constraining.
Qt for Embedded Linux requires writing a screen driver, a mouse driver, a
keyboard driver, etc. using API that is not guaranteed to stay binary
compatible. Also, its architecture was designed around frame buffers, and the
code assumes in many places to have access to the pixels themselves. This
architecture is not the best one for OpenGL ES-capable hardware acceleration.
What's more, Qt for Embedded Linux is being replaced by the Lighthouse Project
with Qt Platform Abstraction, which is more suitable for hardware
acceleration. When we switch to Wayland, we'll switch to QPA too (and probably
require a MeeGo 2.0 version).
2) outside Qt: the ecosystem. We want to run many non-Qt applications and the
tecnology that exists from the ecosystem and community. Those currently use
X11 because there's nothing better. Using QWS is not an option. Only when
Wayland is mature will there be an alternative, so we can ask the community to
use Wayland.
> At-least for the handset and IVI based devices where there are memory and
> processing power constraints qt embedded is a better alternative than qt
> X11.
Handset is not so much an issue. X11 runs fine on 256 MB of memory, as
evidenced by Maemo 5 and MeeGo on the N900. Those devices have 600 MHz to 1
GHz of CPU today and are now coming to dual-cores (ARMs, MIPSes, since Atoms
are there already).
IVIs have a different market outlook, but they are also looking at high-end.
Remember that IVIs have a lifespan of 5 to 7 years, whereas handsets get
replaced within 2 to 4. Anyone using ARM11 for IVI today is shooting
him/herself in both feet, in my opinion.
So I don't buy your argument. But even if your argument were true, it doesn't
mean MeeGo must address those segments. Like I said before, MeeGo is
addressing the high-end. And, moreover, I also don't think QWS is the best
architecture or is abetter alternative than X11, like you siad.
QPA / Lighthouse, yes, that is a better alternative. But we need a windowing
server first and Wayland is not ready.
--
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
Senior Product Manager - Nokia, Qt Development Frameworks
PGP/GPG: 0x6EF45358; fingerprint:
E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ MeeGo-dev mailing list [email protected] http://lists.meego.com/listinfo/meego-dev
