[Qt-interest] Is QPainter::HighQualityAntialiasing render hint broken in Qt 4.6?

[Samuel Rødal]

liang jian wrote:
>     I seems that QPainter::HighQualityAntialiasing render hint is
> broken in Qt 4.6. if I run overpainting exmaple In 4.5.3 with
> QPainter::HighQualityAntialiasing render hint the image quality is far
> better than that with QPainter::Antialiasing render hint. But now with
> Qt 4.6, it show no difference, and the image quality is the same as
> 4.5.3 with QPainter::Antialiasing even if I have set
> QPainter::HighQualityAntialiasing render hint. I know Qt 4.6 have
> rewrote opengl paint engine, is this a side-effect or a bug?

That's a render hint that's unfortunately not implemented in the new GL 
2 paint engine that's the default in 4.6.0. If you want the old paint 
engine you can use QGL::setPreferredPaintEngine(QPaintEngine::OpenGL); 
before creating the QApplication object.

It's not guaranteed that we'll implement HighQualityAntialiasing for the 
OpenGL2 engine, since that feature has proven to be very expensive 
performance wise.

--
Samuel