[Qt-interest] Why destroy QPainter after drawing?

[Jason H]

I don't know for sure, but I would expect that each top level paint() gets a painter, which is passed to children and modified as needed by the kids. 

i.e. a child could instill alpha(0.5) and that should be propagated to that kid's kids. If you hold onto a painter, the parent's painter could change (if the user changes display bit depth, for example) and your old painter would paint garbage, leading potentially to application crashes. 




----- Original Message ----
From: Rohan Prabhu <rohan at rohanprabhu.com>
To: qt-interest <qt-interest at trolltech.com>
Sent: Wed, June 30, 2010 12:37:21 PM
Subject: [Qt-interest] Why destroy QPainter after drawing?

In the documentation for QPainter, it says that "Remember to destroy
the QPainter object after drawing", but doesn't provide a rationale as
to why. Why does it say so? Why is destroying QPainter necessary after
painting?
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