A really neat feature that Arthur in Qt4 was lacking was support for perspective transformations. QMatrix is an affine transformation class. Even though our docs advertise it as a 3x3 matrix it's actually 2x3. I've been wanting to do perspective transformations in Qt for a while. With Qt 4.2 frozen I had a chance to sit down and work in the main branch for the last two days. As a result I have a very basic support for perspective transformations in Qt. I added a QTransform class which is a true 3x3 matrix and gutted most of Qt where I replaced QMatrix with QTransform. Now it's possible to do projections of any kind of Qt element. That includes images like Konqy here:
but also all other Qt elements, like here a button with a label and icon:
All of which allows one to create a really nice looking 3D like looking effects in all Qt apps.