QT irregular shape antialiasing

Many people on the Internet use the following methods ：（ Other code is ignored here ）

QPainter painter(this);
// Enable anti aliasing 
painter.setRenderHint(QPainter::Antialiasing, true);// Some are not here true

But it has been tested and compared , Sawtooth still exists , such as QLabel When you put an irregular figure and rotate it, the sawtooth still exists ;

After my test , After modifying the parameters, the rotation saw tooth disappears under the above conditions , The following code ：

QPainter painter(this);
// Enable anti aliasing 
painter.setRenderHint(QPainter::SmoothPixmapTransform);// Modify here 

Use effect comparison ：

（ Before using ）

（ After using ） 

Although it can not be achieved completely without sawtooth , But the effect is much better than before .

ha-ha , come on. ！ Oulige ！