[Qt-interest] QPainter: It is not safe to use drawPixmap() outside the GUI thread

[Mihail Naydenov]

----- Original Message ----
> From: Serge <mb0 at km.ru>
> To: qt-interest at trolltech.com
> Sent: Wed, October 28, 2009 1:36:59 PM
> Subject: [Qt-interest] QPainter: It is not safe to use drawPixmap() outside the GUI thread
> 
> Hello,
> 
> I have QT application, which renders SVG on QPixmap in a separate 
> thread. Separate thread is needed because rendering takes a lot of time.
> this application was developed in QT 4.3.3
> it worked fine without warnings.
> 
> now i built it in QT 4.5.2
> when it works in debug output window i can see a lot of messages:
> QPainter: It is not safe to use drawPixmap() outside the GUI thread
> 
> Is it critical warning?
> Can i leave rendering the same or i need to rewrite rendering so that it 
> would not use QPixmap? What thread-safe alternative of using QPixmap?

You should use QImage instead.

Than you can drawImage() or QPixmap::fromImage() if you really need a pixmap (faster onscreen)

MihailNaydenov


> 
> Thank you!
> 
> --
> Serge
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