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In-Depth With Qt 4.4

QtPi writes "Trolltech has announced the availability of Qt 4.4, the cross-platform software development framework. Ars Technica has an in-depth look at the release, which include an integrated WebKit-based HTML rendering engine, the new Phonon multimedia framework, support for Windows CE, and significant improvements to the QGraphicsView system. 'Qt 4.4 brings a lot of rich new capabilities to the toolkit that are sure to please open source and commercial software developers. It sounds like Trolltech already has some nice plans for Qt 4.5, and we will hopefully get to hear more about the long-term roadmap after Nokia completes its acquisition.'"

14 of 253 comments (clear)

  1. Widgets in QGraphicsView look *really* promising by Enleth · · Score: 5, Informative

    Graphics View alone is an extremely powerful tool - now it seems to be able to do things no other toolkit comes even close to. I can't wait to use 4.4 in an application I'm developing right now (a game map editor), this feature will allow me to make some parts of the user interface a whole lot simpler and more intuitive, throwing away a bunch of docks and toolbars in favor of a more interactive workspace.

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  2. Help get Qt working in Firefox by Anonymous Coward · · Score: 5, Informative

    Vladimir just posted about working more on Qt for Firefox - http://blog.vlad1.com/2008/05/06/well-isnt-that-qt/ - the more devs that can help, the quicker this will happen.

  3. Re:Qt still has a point? by timmarhy · · Score: 3, Informative
    "Qt is much more portable"

    bullcrap. name a platform qt works on that wx or gtk doesn't? i admit gtk looks crappy on some, but wx looks native on all of them AND provides a shit load of default widgets

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  4. Re:Qt still has a point? by Rhapsody+Scarlet · · Score: 5, Informative

    Nobody needs Qt when there is WxWidgets and/or GTK. Qt's point is moot

    The ZSNES developers for one prefer how Qt works and R. Belmont (of MAMEdev fame) also stated that the only reason he used GTK+ on the Linux port of Audio Overload was because various portions of the code weren't compatible with the GPL. If they had been, he'd have used Qt instead. I also prefer Qt, hence why I use KDE in preference to anything else and why I view the possibility of Mozilla using Qt with some excitement.

    I'd go as far as to say that GTK+'s 'killer feature' these days is the licence. The fact that it uses the LGPL as opposed to the GPL and was open sourced well before Qt is why it's remained so popular. In most other respects, Qt is the better toolkit.

  5. Re:What about Google Earth? by thzinc · · Score: 4, Informative

    It was Keyhole's engineers that made that decision, not Google's.

  6. Sigh, I was hoping for a free WM devel platform... by Yosho · · Score: 4, Informative

    I was pretty excited about the Windows Mobile support in this, until I downloaded it, read the FAQ, and discovered that you have to have the Windows Mobile SDK installed to use it. While the SDK is free to download, you must have Visual Studio (not an Express version) to install it, so developing mobile applications is still going to cost you at least a few hundred dollars.

    So, just a heads up to anybody else who's interested: Don't bother with it unless you have Visual Studio Professional 2005 or later.

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  7. Re:Qt still has a point? by mR.bRiGhTsId3 · · Score: 3, Informative
  8. Re:Why does Qt get such kudos? by Anonymous Coward · · Score: 3, Informative

    I am not sure but reading your post it seems you are under the belief Qt is licensed per application.

    The Qt licensing model is that you a license fee per developer, depending on the number of platforms you want to target.

    One of the key values Qt brings is the single codebase / multiple platform way of developing.

    If you wanted to port a rich client application to Linux and Mac OS/X you would not be able to use your MSDN subscription for much, whereas with Qt you would recompile your app. You would have to be extremely fast and/or have a very low hourly cost not to save money on this relative to doing a rewrite / port / multiple codebase approach (for any non-trivial application).

  9. Re:Why does Qt get such kudos? by Jeremi · · Score: 5, Informative
    But for the cost of one license for MSDN you can only license one application for Qt development, both per year.


    Huh? A Qt license is expensive, but once you have it you can create all the Qt apps you want. At least, that's what my Qt license says. I think you have been misinformed.


    But, per application, recurring per year, its expensive


    Again, there is no "per application" charge. The "per year" charge is if you want support -- if you don't want/need support, just buy the Qt license and don't renew it after a year. You'll still be able to use the version you bought indefinitely.


    And should we port to Linux and Mac OS/X, our licensing fees for MSDN would be £453 (approx $1116) and our Qt fees would be $126,000).


    Are you talking about porting a .net app to Mac and Linux? Most Win32 apps wouldn't be "ported" so much as "rewritten from scratch", and for a non-trivial app the rewrite would cost a lot more than $126,000 in developer time. Maybe C#/.net apps run just as well on Linux and OS/X as they do under Windows, but if so that is news to me. Portability what makes Qt worth the money... being able to support Linux, Windows, and Mac with a single codebase that you only have to write and debug once is a huge win.

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  10. Re:Why does Qt get such kudos? by codemachine · · Score: 5, Informative

    A number of possible answers, with varying degrees of importance/truth depending on your opinions:

    - Because QT is cross platform.
    - Perhaps it saves enough development effort over the MS stuff that it is worth the cost.
    - It has a GPL version on all the major desktop platforms, so fully OSS apps are possible
    - Is compiled instead of interpreted

    There are probably lots more differences between the platforms that I missed as well. Not all of them would favour QT. Depends what you're looking for I guess.

    But it isn't surprising that QT is popular with much of the Slashdot crowd, since it is GPL and supports non-Windows platforms. So I'm not sure why one would even have to ask why people here prefer QT over MSDN and Visual Studio.

  11. Re:Framework hell by SanityInAnarchy · · Score: 4, Informative

    But each of those 100 ko apps depends on a different version of the 10 Mo library. In short, no they don't.

    Using one version of a library with an application designed for one version often results in framework hell. You linked to "dependency hell", which is a solved problem -- see package managers. It is not only possible, but easy, to install multiple versions of the same library. And if the library is reasonably high-quality (like Qt), you're not going to need ten versions of it. On a bad day, you might need two (3 and 4).

    I haven't been on Redhat in awhile, so maybe it's still an issue there. I remember RPM being a bitch, but I haven't used RPM since 2002. On Ubuntu, I have exactly one version of libqt-mt installed, and it weighs in at about 11 megs. And because this is Kubuntu, it's installed already.
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  12. Re:Framework hell by UngodAus · · Score: 5, Informative

    Actually, in Qt we have a mandate for backwards binary compatibility. Only if it's an absolute necessity is binary compatibility broken, and I honestly can't think of a single time in the 4.x stream of code that we have done that. So, your "framework hell" argument is moot. Only the latest version of Qt is "needed", and should support all applications compiled for previous revisions of Qt4.

  13. Re:A note on signals and slots by shutdown+-p+now · · Score: 3, Informative

    So, here is my question: in Qt 4, can we do signals and slots programmatically, or do we still have to use qmake?
    I imagine you mean "moc" ("meta-object compiler") here rather than qmake. You can call moc yourself without any problems, and you can run it from post-build actions for files in your project you need preprocessed. It's all there in UI in VS2008. And, of course, if you buy Qt4, you'll get full integration with all modern VS versions out of the box.

    IIRC, you always could do signals/slots programmatically - after all, moc is not some kind of magic, it just generates all the boilerplate C++ code. It's not exactly convenient, though (not like e.g. boost::signal), precisely because it's not intended to be used manually.

  14. Re:Can anyone recommend some good books on Qt? by Ringlord · · Score: 3, Informative

    I like C++ GUI Programming with Qt 4 very much. Details here http://troll.no/developer/books/2