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

It Sounds Nice

[Jeagoss]

but, is it absolutely essential? In a time where code needs to remain compatible due to the large amount of projects that are depending on that code, huge architectual changes implemented in a large number at one time will just show that the project wont get used for quite a while. It will take time for developers to start supporting the new format, which will leave end users wanting.

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: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.

Re:This is what I really want from Trolltech.

[AugustMoon]

Big deal. There is no law against having your stock owned by questionable companies. Furthermore, no publicly traded company can really control who buys their shares. They are publicly traded, any one can buy or sell the ownership.

It doesn't automatically mean Trolltech inherits all the vices of every one who owns shares.

I would not be worried or even morally concerned until Trolltech's business decisions go south. Minor share holders don't dominate a company. Even 5.7% isn't a lot.

QT4

[SlayerDave]

I have recently spent a good deal of time programming with QT3. While QT is the best C++ GUI library and application framework, I think it needs some improvement. Here are my gripes, in no particular order.

First, the signal/slot mechanism really bugs me. I am annoyed with the need to use non-ANSI C++ techniques (e.g. public slots, moc) to achieve results that could easily be done with legal C++ code. While not strictly illegal, the use of the SIGNAL and SLOT macros, along with the Q_OBJECT macro, are not very good techniques. Specifically the reliance on macros to achieve basic GUI functionality violates a key principle in Meyers' "Effective C++", namely avoiding reliance on the preprocessor.

Second, several GUI widgets do not have a proper separation of data from view. I am thinking specifically of QTable and QListView. A better approach, from an OO design perspective, is the one taken in Java Swing. The JTable and JTree provide a nice mechanism for separating the data model from the GUI display. I find it obnoxious to have to subclass QTable and build-in data model methods to achieve results that would be cleaner under a Model-View design paradigm.

The QT online documentation is not easy to navigate. They should take a lesson from the Java API docs and reorganize the QT docs along those lines.