[Qt-interest] Xor'ing in paint event

[Ender EREL]

Ian Thomson wrote:
> Hi
> 
> This causes a stack overflow because calling the paintEvent is virtual, 
> meaning that calling it on your 'this' pointer will call 
> derived->paintEvent, even if you cast your this pointer to a Base type. 
> So you're calling the function recursively forever, overflowing the stack.
> 
> A better solution would be to add a function to the base class called 
> 'draw' which takes a QPainter*. In the base class paintEvent, just make 
> a QPainter in the standard way, and call the draw function. In the 
> derived class, open a QPainter on an appropriately sized QImage, and 
> then pass that along to the draw function.
> 
> Cheers,
> Ian.
> 

At first i thought of that too, but the base class is from a library 
that another team at my company is developing therefore i am trying to 
find a solution that does not require modifying the base class.

Best Regards.
-- 
Ender EREL