What to Expect From Qt 4

An anonymous reader writes "A presentation given by Matthias Ettrich (director of Qt development, author of LyX, and founder of the KDE project), was given to the annual KDE Developer's Conference in Nove Hardy, Czech Republic. In this presentation, Matthias details what's going to be new in Qt 4.0, which will be used as a base for the next version of KDE after 3.2. Apparently, Qt 4.0 will not only include faster startup times and lighter memory usage, but will have sweeping architectural changes, including a splitting of Qt's GUI classes and non-GUI classes."

Comments

Faster?

[Kenterlogic]

I have alwways preffered Gnome to KDE because of speed issues (and the new Gnome is a lot prettier). But if this new base is much faster, then I may be forced to start using KDE again. Then again, my G5 should be arriving soon-- so forget Linux.

Re:It Sounds Nice

[siliconwafer]

The lighter memory usage and faster startup times sound very nice. Maybe not essential, but nice.

Re:It Sounds Nice

[stratjakt]

Qt 4 mostly tries to preserve source-compatibility with a little search and replace and a COMPAT compilation switch. More porting will be required for styles and code that uses the meta object system directly.

Out with the old, in with the new.

Developers can adapt or fail. It doesnt seem wise to quit working towards better systems because some guy doesnt feel like replacing his widgets.

Re: RTFA!

[Rimbo]

Jesus, I was wondering when someone was going to say this. Qt developers obviously aren't reading slashdot. other than you and me, that is :D

I think the large number of complaints is that although source-compatibility is -basically- maintained, you still have to recompile your apps. One of the nice things Microsoft has done is that you don't have to recompile your Win32-based app to work in .NET -- well, not completely, anyhow. This does have the side effect of dirtying up the API a bit. So it's a trade-off. Backwards compatibility does make GUIs easier for people to adopt -- who wants to constantly have to download new apps to work with the latest version???

What I would like to see..

[ErisCalmsme]

Is more apps that require QT but not all of kde to run. That's why I use gtk apps... because most of them dont require gnome. There are gnome apps of course, and there are progs like Gaim that will give you a little somethin' extra if you have gnome installed, but you don't need it... Are there any qt apps that dont require kde to be installed?

gcc dynamic linking?

[4of12]

A couple of years ago someone on the KDE team posted a nice analysis of the performance bottlenecks associated with dynamic linking, C++, and gcc, particularly as regards Qt use.

So I have to wonder, with Qt 4, KDE 3, gcc 3.3, how many of the performance problems remain?

Re:gcc dynamic linking?

[IamTheRealMike]

That's what all the talk about reducing number of symbols and relocs is about - KDE got hit really really hard by the way it requiries lots of fixup at startup time in the linker. In some cases it was THE biggest drain on startup time. By reducing the number of symbols in the code, you reduce the work needed to dynamically link it all, so improving the speed.

Though, I can't help thinking that prelink is a better solution to that problem. But whatever, they are surely aware of that technology by now.

use of the standard library

[Eponymous Coward]

I'd like to see more use of the standard library. The traditional complaints of poorly conforming compilers is mostly just history. Except for support of the export keyword, most C++ compilers and standard library implementations are now quite good. Most platforms even have several excellent compiler / library combinations to choose from.

Even though it would be hell for already existing apps, I would love to see use of standard library components rather than the re-invented QT versions. And even in those cases were the QT versions have extra features, I still think the advantages of using a library that is already familliar with most C++ programmers outweighs the disadvantages. Of course, that's just IMHO.

ec

Re:It Sounds Nice

[Otter]

Developers can adapt or fail.

Remember, though, that we're talking about volunteer developers. If they fail, there's no one rushing in to take their customers. I remember when the KDE 3 plans were being made, there was a recognition that KDE's weakness is in the number and quality of apps and so there was a goal of keeping the APIs stable for as long as possible.

Now, greatly improved startup time would obviously be a huge reason to switch as soon as possible. Since pure Qt apps already start much faster than KDE apps, though, I wonder how much speed KDE would really gain.

Very nice. But they forgot one minor thing:

[master_p]

I don't have any major complain from Qt, as I have been using it a lot in our company and found out that it is the best.

I only have this problem: the TreeView widget is single-linked. This a major problem for us, since our apps contains lots of trees. We have to do a lot of tricks, like keeping a pointer to the last item all the time.

I've posted this on the Qt newsgroup but I was ignored. Although many people have complained about it, Qt engineers ignored us. I think they should fix it in version 4.

Other than that, Qt is indeed the finest toolkit out there. It simplifies development a lot, and it fills the great void that exists in C++ libraries. It's really like the Java libraries or the .NET libraries, providing almost everything needed under the sun.

The biggest advantage of it is that it works as expected; in other words, you just create one widget inside the other, and voila, there is the app's gui. You can even do it programmatically, without the KDesigner.

Finally, it does C++ justice. It's the only library that shows how powerful C++ can be. After having used Qt and Java, I may safely say its up on par with Java...even better I would say, since it uses all of C++ capabilities, including the most important one: templates.

Re:This might mean something to me

[phurley]

I use and enjoy wxWindows, but I do not think your criticism of QT and their licensing is very fair. They have a completely free license (GPL) which you can use - to create completely free applications. They have commercial licensing (admittited too expensive for "shareware" type applications).

There is a completely reasonable middle ground where you can release your application as GPL code - which you can legally sell for any price you want - yes you need to provide the source code to your customers (not a bad thing) and yes they can then give it away to their friends, family and even people they pass on the street - but if your application has true value - they will probably be more than willing to pay for it (especially if it is as low cost as you claim). Many users are not sophisticated enough to compile their own binaries and the making the "official" binaries what you sell - is legal.

Now if you are just upset because they will not give you (or sell at the price you pick) their library for you to use in closed source for profit applications, then it is far better that you found a different library.

How about more standard C++

[Ed Avis]

Is it too much to ask that the next Qt will use the standard C++ string class instead of its own reinvention and kitchen-sink-itis that it suffers from at the moment?

AC Comment from other Canopy Employee

[bstadil]

Since my comment has been modded a Troll I think you should read this posting from another Canopy Company employee.

Quote:

As an employee of a company in the same office buildings as SCO and partly funded by Canopy Group, I strongly encourage a boycott of all companies funded by the Canopy Group.

There was a lot of buzz about mergers a few weeks ago. It seemed that everyone was going to join into one large company called, you know it: SCO! .......