The Independent Qt Tutorial has been updated with a new chapter on the Qt canvas module. It consists of examples and in-depth discussions. The Independent Qt Tutorial is a book introducing the different areas of Qt step-by-step with task orientated chapters rich on examples and a detailed discussion of the different areas of the Qt toolkit.
I think that QCanvas is quite unknown and underused. However, it is a bit hard to get all stuff working with it, I once fought for a while to get the main graphics for a simple strategic game working with QCanvas, but after a while I gave up. It was easier to use SDL, even though SDL is more low level.
The Qt tutorial is a good and ambitious project, I look forward to the upcoming chapters.