Trolltech Releases Qt 4.0

Trolltech has released Qt 4.0 both under commercial and GPL licenses for X11, Mac OS X and MS Windows. It is the first time that a MS Windows GPL edition is available. To celebrate the release Trolltech employees have created a song and a music video (Bittorrent download, Ogg Theora version). Read the Qt 4 Overview and the online Qt Reference Documentation for more information. You can download Qt from or from one of its mirrors. Work on KDE 4 has already started with making a development branch of KDE compile and run with Qt 4.

Unlike previous Qt releases, Qt 4 is a collection of smaller libraries which also allowed the restructuring of commercial offers into Qt Console for non-GUI development, Qt Desktop Light replacing the Professional and Qt Desktop comparable to Enterprise editions.

There are five new technologies that are new within Qt 4:

  • Tulip, a new set of template container classes.
  • Interview, a model/view architecture for item views.
  • Arthur, the Qt 4 painting framework.
  • Scribe, the Unicode text renderer with a public API for performing low-level text layout.
  • Mainwindow, a modern action-based mainwindow, toolbar, menu, and docking architecture.

In addition, the following modules have been significantly improved since Qt 3:

  • A fully cross-platform accessibility module, with support for the emerging SP-API Unix standard in addition to Microsoft and Mac Accessibility.
  • The SQL module, which is now based on the Interview model/view framework.
  • The network module, with better support for UDP and synchronous sockets.
  • The style API, which is now decoupled from the widgets, meaning that you can draw any user interface element on any device (widget, pixmap, etc.).
  • Enhanced thread support, with signal-slot connections across threads and per-thread event loops.
  • A new resource system for embedding images and other resource files into the application executable.

The Qt Designer user interface design tool has been rewritten as a collection of interchangeable components. It now features support for MDI and SDI modes and supports custom widgets. The project editor and the code editor have been dropped.

Qt 3 based applications have to be ported to be able to run with Qt 4. A porting guide, a porting tool as well as a Qt3Support library for obsolete classes are provided. Trolltech aims to maintain the Qt3Support Library for the lifetime of the Qt 4 series, and will also support the Qt 3 series for a minimum of two years beyond the release of Qt 4.

Some known issues are listed which are expected to be fixed in upcoming maintenance releases of Qt 4.0. Qt 4.1 will features certain advanced Qt 3 features rewritten for Qt 4 which are now only available in the Qt 3 support library (eg. Qt 3 canvas, Qt 3 syntax highlighter). It is planned be released late in 2005.

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by efegea (not verified)

(...) Work on KDE 4 has already started with making a development branch of KDE compile and run with Qt 4 (...)

Is there any documentation or how-to about how can I compile and test that?

by Anonymous (not verified)

Look under /branches/work/kde4/ on

by Nicolas Goutte (not verified)

The modules are under trunk/branches/work/kde4

You need unsermake 0.4 (trunk/kdenonbeta/unsermake), if you are not using it already. (You can use the same version on KDE 3.x too.) Automake does not work (and will never work).

You need to compile Qt4 as debug not as release, otherwise it does not work.

There are perhaps other traps (and please do not await wonders...)

Have a nice day!

by hannes hauswedell (not verified)

will kde4 be the first release to fully support qt4? or is there any other *easy* way to get a kde desktop, with kdevelop that makes use of qt4?

by Nicolas Goutte (not verified)

There will probably not be any easy way, as Qt4 is not source compatible to Qt3. (That is why Trolltech has made a porting tool.)

Have a nice day!

by Henrique Marks (not verified)

Many thanks for not being musicians. It was the first time in my life that i used remove file from inside amarok, instead of remove from playlist. The song is terrible. But i know that bad advertising is good, so everyone who read this will try the song anyway.

PS: Thanks for Qt. But for this i have no words.

by Anonymous (not verified)

At least it's better than the Free Software Song ( :P

by Anonymous (not verified)

But not better than John Ashcroft's "Let the Eagle Soar"

by fast_rizwaan (not verified)

Song was ok, but Dance was laughable ;), had a hearty laugh watching trolls dancing :D

by Ian Monroe (not verified)

Be sure to watch the .ogg or .mov with mplayer or somesuch to get the full music video experience. Personally I think its so lame that goes around and is actually incredibly awesome. ;)

/me does the Qt 4 Dance

by JC (not verified)

The guy speaks with the same horrible french accent as myself. Lol

by cartman (not verified)

Congratulation for the Qt4 release and the video rocks! :)

by binner (not verified)

Small addition, Trolltech has now a public bug tracker:

by ac (not verified)

Excellent, was about the time they finally opened that up.

by cies breijs (not verified)


by LuckySandal (not verified)

Any possibility that the new low-level style API will help spur development of a common widget set / backend for Qt & Gtk on Linux is in real need for a standard GUI, and having one would allow GNOME and KDE to work closer together, always a good thing!

by James Livingston (not verified)

I haven't looked in detail at what the low-level APIs provide, but some of them already have an equivalent for GTK. Whether or not we'll see them merge is something we'll have to wait and see, but it would be a good start.

Glib provides container classes like Tulip.
I'm fairly sure Cairo is similar to Arthur.
Pango is the equivalent text renderer to Scribe.

by ac (not verified)

I doubt such a merge would be widely used unless it's both compatible with Trolltech's Qt and available for all systems theirs is (which is highly unlikely if GTK is to form the base of the merger).

by mmebane (not verified)

I don't know if that would happen, but the new API sounds like a good thing for the Gtk-Qt Theme Engine.

by ac (not verified)

common do the Qt4 dance...


by melenas (not verified)

The song is great and the video is very funny, but in mov format kaffeine fails (extrange when I could watch other files in mov format), so I encoded to MPEG4 and mp3.

Could I made a mirror of this video and mp3 on my own server? or there is any copyright restriction?

By the way, Qt4 looks nice :-)

by Corbin (not verified)

If I download the video it works in Kaffeine (but not KPlayer), but the audio doesn't work in either, oh well.

by kiriuja (not verified)

Just tested and confirmed that KPlayer correctly autodetects and plays the video both locally and directly from The codecs are ffh264 for video and faad for audio, MPlayer is 1.0-pre7. You may want to make sure you have an uncrippled MPlayer binary, like the one from Marillat ( Also make sure you have the correct version of libfaad, for example if you use Marillat's binaries you should also use Marillat's libfaad, rather than the one from rarewares for example.

by macflurry (not verified)

i hope i like it

by charles (not verified)

With the release of QT4, I hope Adobe will now quickly work on, and release its reader based on QT4. Adobe's newest reader (ver. 7.0) for Linux sucks in the file-save or file-open dialog to say the least. Besides, I think that for those having nothing like *GTK* but a KDE environment, the reader will load faster than the current GTK based one.

by Martin Stubenschrott (not verified)

since adobe rewrote the reader from motif to gtk for the version 5->7 upgrade, I don't think they will change it again any time soon.

by Roland Wolf (not verified)

How about porting all Adobe tools (including Dreaweaver) to Qt?
Lots of people would buy a Creative Suite on Linux today. I wonder if there are hidden reasons for not serving the Linux market (-- insert your favourite paranoid phantasy here --). In the long run KDE will fill the gap just as KPDF is already a wonderful replacement for Acrobat Reader. The only weak spot of KPDF is the improper handling of truetype font kerning. Qt 4 Scribe promises to fix it.
Adobe will need to run on a couple of different platforms soon. The Windows platform is about to fork to Win32, .net and Avalon, the Mac will fork to Power and i386 hardware. I do not see an economic development strategy other than using Qt.

Go KDE go!

by cies breijs (not verified)

> Adobe will need to run on a couple of different
> platforms soon. The Windows platform is about
> to fork to Win32, .net and Avalon, the Mac will
> fork to Power and i386 hardware. I do not see an
> economic development strategy other than using Qt.

Good point, there are indeed too many toolkits on the horizon :)

Adobe already has one (can i say: 'experiment') program using Qt, called Photoshop Album ( More info on that here:

by illogic-al (not verified)

"I do not see an economic development strategy other than using Qt. "
Don't quit your day job then.

by Eric Laffoon (not verified)

> How about porting all Adobe tools (including Dreaweaver) to Qt?

Since it's closed source then of course Adobe would have to do that. Supposedly there was work in progress to port Dreamweaver to Linux a year or two ago. Where is it and where is the hype? Reading things like this are distressing to me personally. Quanta Plus is here _now_, already native KDE, is already superior for coding like PHP and already has a superior rendering engine with KHTML. Currently development work is being done to make a new generation visual mode, integrate with the KDevelop framework and enhance other capabilities like scripting with Kommander. It also has a fully DTD compliant markup engine and manages XML DTDs on the fly. One of the goals for KDE 4 is to manage XML with XSLT on the fly. All the feedback I've gotten from people who have used Dreamweaver and Quanta is that there are less and less reasons to use Dreamweaver. Quanta is not targetting a feature for feature replacement but is targetting a new generation tool with a goal of nothing less than being the best.

If you can get software that is free as in freedom and free as in beer and it is deeply native KDE, mature and based on a more advanced architecture would you prefer a commercial product? Since Quanta uses sponsored development a contribution of a lot less than the retail cost of Dreamweaver can go a long way to helping to make sure that when (if) it finally shows up on Linux you have no reason left to downgrade.

by Manuel Valladares (not verified)

Hello Eric,
Any plans to port Quanta to Windows and/or Mac?

I think it would be a very good idea to expand the 'market' of the program, and now with the GPL version of the Qt it would be possible to offer it for free.

I don't know how hard it will be because it probably has many KDE dependencies.

Thanks for supporting such a great software,

by MandrakeUser (not verified)

"The reader will load faster than the current GTK based one."

Well, if you have enough RAM (about 512Mb these days), the gtk components that you need will stay in the cache after being loaded from disk for the first time, and next time they'll be loaded from mem-cache, not from the disk. Note that your argument goes both ways right ? Some people use gnome-only. Adobe will definitely not release a product with two different libs just to keep as happy :-)))

I still would love to see _everything_ written with the Qt/KDE libs. But that's _my_ preference and _my_ opinion. Other people like other libs, let's all coexist. Long life to


by me (not verified)

Cool, then I , as a non KDE user can complain about Adobe using Qt and the slow startup and bloated file opener.

by mikeyd (not verified)

KDE people tend to believe you should actually be able to find your files rather than having to click to open up a dialog and then get about 4 pixels to browse your filesystem with.

by Jakob Petsovits (not verified)

C'mon, let's not get into flaming. Both approaches have their strenghts, so let's just keep promoting the ones we like instead of lowering the other ones.

by mikeyd (not verified)

What's the strength of having a much smaller area to browse your files with? I agree that there are advantages to gnome and its way in some areas, but the file dialog is just stupid.

by fast_rizwaan (not verified)

Thanks Trolltech for releasing QT for windows and mac under GNU/GPL. Now we can see more QT applications in Linux, Windows and Mac too :)

I wonder how KOffice for Windows would look like ;)

by Anonymous (not verified)

Qt/Mac is available under GPL for quite some time already now.

by blacksheep (not verified)

Qt was already licensed under GPL for Mac for quite a long time!
Windows is a first.

by 42 (not verified)

do the qt4 dance! %-}

this is beyond embarrassing... but I'm sure it was great fun for all those dancing around in the vid ;)

- 42

by Amadeo (not verified)

First there was linux
Than there was Mac
Now we put Windows
on the open source track...

The only thing better than that was the beta (alpha?) release of KDE codename krocodile theme... Go, Schnappi, go...

by blacksheep (not verified)

Just wondering, which one is Zack "The Hacker" Rusin? :)
The video's credits seq just says he is one of "The Cute Four".

by Anonymous (not verified)

The cutest one of course. Still question open? OK, the most left after leaving the computer.

by suy (not verified)

This guy at the bottom is Zack Rusin:

by AC (not verified)

And why is there a credit for "Stand-in for Zack"?

by Anonymous (not verified)

Because there was a stand-in for Zack for "within the computer" scenes.

by MandrakeUser (not verified)

Does the fact that there is now a GPL official Qt windows release mean that pyqt for windows will also have a GPL version ? That's gonna boost PyQt as a fantastic cross platform rapid dev. environment !

Maybe even PyKDE, are there any plans to natively port the kdelibs to the evil empire ?

by smt (not verified)

Yup, PyQt4 will be GPL'd in Windows

by MandrakeUser (not verified)

Cool, thanks!

Win PyKDE of course will depend on what happens with Win KDE ... oh well, one step at a time

Personally, I only use windows at work 'cause I have no option. It sucks, and I'd love to be able to use some kde apps ...