Some of my colleagues on the graphics team have been writing graphics dojo demos with impressive speed and with a rainy weekend I thought I'd get into the action. As I'm regarded as the text guy I thought it would be fitting to have a demo that uses text, so I made a text effect class that animates text fading in and fading out.
One thing that I see a lot of people do is that if they want to zoom into text, they change the fontsize. There is a fundamental problem with that approach as text doesn't scale linearly (due to hinting). So in Qt4 we have a much simpler and more powerful way of scaling text that fits better in graphics concepts. You simply scale the QPainter during painting. This means that if you call myPainter.scale(2,2); your 12pt font will suddenly appear as a nicely scaled 24pt font. Or, more accurately, it will show the original text at 200% zoom.
This is very simple and due to us reusing the same font settings we avoid recalculation and text layout. So it will actually be quite fast. So fast that you can animate it quite smoothly. As is shown in the demo.
There is not much more to say about it, so just grab the code and run it! svn checkout svn://labs.trolltech.com/svn/graphics/dojo/zoomingtext