QPixmap::grabWidget failure

[DonSev]

Hi Guys,
I'm working on to an application, and I want to used QPixmap::grabWidget function to save a pixmap of my widget. The build is well, but I have an error when I run the application:
@ASSERT failure in QGLPainter: "begin() has not been called or it failed", file painting/qglpainter.cpp, line 770@
This is a part of my code:
@ QPixmap originalPixmap0 = QPixmap();

// originalPixmap = QPixmap::grabWindow(My_Widget->winId());
originalPixmap0 = QPixmap::grabWidget(My_Widget);@
If I use the grabWindows, it's work well. But I want to use grabWidget to hide my widget and still have it on my Pixmap.

Does anyone can help me to found where is came from?
Thank you
Don

[andre]

I'm not sure gradWidget works with an openGL widget at all...

[DonSev]

Thanks for the reply.
Thereby, from what you said, I can not use grabWidget, and I have to used grabWindow. But, it is not possible to get a pixmap from an hidden Qwidget with grabWindow, is it?
What I want to do is some like:
@My_Widget->hide();
...
QPixmap originalPixmap0 = QPixmap();
originalPixmap = QPixmap::grabWindow(My_Widget->winId());@
Using that way, I want to have a Pixmap of my widget, without displayed it on the screen. I have tried this, and the saved QPixmap was a screenshoot of my desktop, not an image of my widget.

[andre]

I said that I doubt that it works, not that I'm sure it does not work. It would the first thing I'd look into to find the cause of your issue.

I don't know if there are ways to render openGL into a pixmap without it being displayed on screen.

[DonSev]

Thanks for your answer. I gonna have a look on this. And I hope to find a way to do this.