[Development] The place of QML

Kate Alhola kate.alhola at gmail.com
Fri May 18 10:21:48 CEST 2012

On Thu, May 17, 2012 at 1:35 PM, Atlant Schmidt
<aschmidt at dekaresearch.com> wrote:
> Peter, et al.:
>> We don't wanna use obsolete stuff with a "architecture from
>> the 90s" in times where "graphical technology has moved on" (Thiago).
>  Computer architectures don't necessarily "become obsolete".
>  Oh, trends come and trends go, but the fundamental concepts
>  go on forever. For example, Linux is quite popular even
>  though it is arguably a "computer architecture from 1970".

Computer architecture don't necessarily become obsolete but also
it could as easily become obsolete. There is no rule saying either.
Many "core" technologies like how programming languages work ( C/C++)
or how operating systems, filesystems etc work have been very stable
technologies and there has been only minor evolution. C/Unix skills
from 80's are still mostly valid today.

On other sections, mostly in user interface there has been rapid
evolution and several
revolutions that have changed all scene. You can just count, Unix/C
started from typewriter
terminal age when UI was line based fully modal dialog. Now this is
fully obsoleted from mainstream
users and remains as coders programming language. Then age of crt-terminals and
text based forms UI, once again fully obsoleted from everywhere. Then
next revolution was
windowing UI with mouse, it got about current form in first Macintosh
in 1984 and after that
there was been very little evolution. You cant say that moving from
typewriter to windowed UI
is just a trend, it was total paradigm shift. QWidgets are designed
perfectly fit to this 1984 paradigm.

Invention of current mobile finger based UI was a start of next
revolution and once again we
can't say that it is just a trend when users move from
desktops/laptops to tablets and handsets
and all computer market is shared again.

At the moment, Qml is only reasonable solution for mobile applications
for tablets and handsets
but at the moment QWidgets are still perfect match for desktop apps.

There is a big question: why any more make application that runs on
desktop only and needs major rewrite for mobile
platforms. Why make QWidget UI and then rewrite for Qml UI for mobile
or why make application for
desktop only. I agree that there are a many applications that are
desktop only like CAD programs etc
but for all other appls. It would be much better solution to make C++
core and then make Qml UI for
desktop and other for mobile.  I have used this method personally and
based on my personal experience
making separate Qml for desktop and mobile is less than 1% of work.
Much less than making desktop UI
with QWidgets and then mobile with Qml.

Then the other big question, what happens in future and should we
prepare for it rather than slowly adapt on it.
It is already known that tablets sell more than desktops and it is
predicted that they outsell laptops on 2015
but i bet that it happens earlier, may be end of 2013. I have been
using iPad since first model and I have also
couple of Android tablets. When I count "normal" usage, web, email
etc, I can do everything with tablet. If
I need write longer mails, I can use bluetooth keyboard. There is
still place for laptops and even high end desktops
for special use like software development, CAD programs etc but that
can be counted as special use.

I would like to say, that in most cases, applications should be
written so that they will also run on mobile because
world is moving to that direction.

>  Often, the proponents arguing for "new and improved" are
>  simply arguing for the position they think will be most fun
>  to work on; after all, it's always more fun to break exciting
>  new ground than it is to have trod the same old sod yet again.
>  But many of these new approaches are just "fashion" and if you
>  wait a few years, fashions will change again and "old and
>  obsolete" will be back in fashion (and often, simply because
>  good sense has returned to the design community).

Moving from typewritter to crt was not a fashion, moving from crt to
windowing UI was not a fashion,
moving to mobile is not a fashion but permanent shange.

>> Most people don't care what happens under the hood (QWidget
>> or QML) when good desktop support is available.
>  And some of us *DO* care very much what goes on under the
>  hood. Me, I live in an embedded world running on a ~450 MHz
>  processor with very limited RAM and graphics. There's just
>  enough "stuff" there to make the traditional Qt approach
>  work (just barely) but if the only choice Qt intends to
>  offer me in the future is going to burden me with the
>  overhead of a JavaScript (or even web) runtime, then I'm
>  going to need a new graphical framework.

There is always some special cases as there are cases of command line UI
or text-forms UI.


>  Old and obsolete worked for me; New and improved (in this
>  case) clearly isn't likely to.
>                       Atlant
> -----Original Message-----
> From: development-bounces+aschmidt=dekaresearch.com at qt-project.org [mailto:development-bounces+aschmidt=dekaresearch.com at qt-project.org] On Behalf Of Peter Kümmel
> Sent: Thursday, May 17, 2012 02:12
> To: development at qt-project.org
> Subject: Re: [Development] The place of QML
> On 16.05.2012 20:31, qtnext wrote:
>> I am using Qt since 12 years or more... I have done a lot of work using qwidget, qgraphiscview, ....
>> I have done some small apps with qml to display media : it works very well ... just the animation are a a litlle bit
>> jerky and work not well on very small computer ...
>> But now that Qt5 is here : the alpha seems very promising regarding performance ... and I have started a new big desktop
>> application and I plan to use only Qml and it seems very promising .. I am sure that Quick2 is the way for new desktop
>> application : We only need Qt desktop components, treeview, ... and it will rocks :)
> Yes, that's the point. Most people don't care what happens under the hood (QWidget or QML)
> when good desktop support is available. But currently for desktop apps you have the choice
> between a "obsolete architecture" (Thiago) and an incomplete QML stack.
> Non technicians don't care about if QWidget is done or not if it fits the needs,
> but we are developers! We don't wanna use obsolete stuff with a
> "architecture from the 90s" in times where "graphical technology has moved on" (Thiago).
> But on the desktop we are forced to when we wanna a feature rich/complete framework.
> So all the QML<->QWidget discussions are mainly because there is no complete Qml support on the desktop.
> Desktop support has no high priority more anywhere.
> It couldn't be so complex to make good Qml support on the desktop, simply throw
> 5 man years on it (shouldn't be impossible when there are already 200 Qt developers
> at Nokia alone). But it doesn't happen because nobody wanna invest in the desktop.
> So all you can do is using a system with a "obsolete architecture", diving deep
> into QML and writing your own desktop elements, or waiting another one or two years.
> And I don't like any of the options.
> Peter
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