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Month: February 2012

Re: [trinity-devel] Trinity qt4 port?

From: /dev/ammo42 <mickeytintincolle@...>
Date: Mon, 13 Feb 2012 22:10:38 +0100
On Mon, 13 Feb 2012 14:50:42 -0600
"Timothy Pearson" <kb9vqf@...> wrote:

> > On Sunday 12 February 2012 02:20:38 Timothy Pearson wrote:
> >> These are the exact reasons I stopped to the move to Qt4 and
> >> picked up maintinance of Qt3 (now becoming TQt3).  I gave the
> >> conversion effort my best shot (which took many, many months of
> >> effort) and stopped once it became apparent how extensive Qt4's
> >> limitations were (especially in drawing operations and native X11
> >> window handling) and also how buggy Qt4
> >> really is.
> > May I ask for the benchmarking results? I am seriously interested
> > here as I
> > think that I can provide you some valuable help here. My fear is
> > that you had
> > an incorrect benchmark (the experts call that phoronixing) and that
> > your decision is because of that on false grounds.
> >
> > Especially important is to consider that graphics cards, drivers,
> > what you render (widgets vs scenes), which Qt graphicssystem you
> > use seriously influences the result. E.g. rendering widgets with
> > raster might be a bad idea.
> >
> > Cheers
> > Martin
> I do not have any benchmarks handy at the moment, although this is
> simply due to the length of time from those tests to the writing of
> this message. The upshot was that Qt4 is significantly slower when it
> comes to rendering raster graphics (as you mentioned), and also when
> large numbers of widgets are displayed on-screen.  If I understand
> some of the Qt changes, the raster performance was improved somewhat
> in the latest versions of Qt4, but I don't know if the other problems
> were addressed.
> As an aside, 3D graphics hardware is not only expensive, it is also
> one of the most proprietary and least-understood components in a
> typical computer (it also tends to burn out a lot, at least that is
> my experience with anything other than an enterprise-grade nVidia
> Quadro card).  If nVidia and ATI experienced supply shortages (don't
> laugh, remember the recent hard drive scarcity due to flooding in
> Thailand) I would still need to be able to use my computers with
> not-so-great backup graphics hardware, and possibly without good
> OpenGL support.
Almost all less than 5 years old PC hardware has either a nVidia, ATI or
Intel GPU, that is not necessarily powerful but definitely has enough
power to render standard controls with OpenGL.
> More practically, even slightly sluggish performance is quite
> noticeable to power users.  Many applications, upon converting from
> Qt3 to Qt4, appeared to slow down noticeably.
Even with a common Qt-internal style such as CDE or Win9x ?
> These are just my $0.02 and experiences in working with Qt 4.7.  I am
> open to looking at Qt4 again once Trolltech fixes the raster graphics
> problem for good.
It will be "fixed" with Qt5, which will have OpenGL ES 2.0 as the only
graphics system. It had better work well with llvmpipe...
> Tim
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