[PyQt] Threads with PyQt. Qt's or Python's?

Frédéric frederic.mantegazza at gbiloba.org
Tue Feb 3 11:24:45 GMT 2009

Le 3/2/2009, "Giovanni Bajo" <rasky at develer.com> a écrit:

>> The documentation says that a QPainter can only paint on QImage, QPrinter
>> and QPicture, but not on QWidget and QPixmap (it seems that painting on
>> QGraphicsItem works fine, as I don't have warnings; can you confirm?).
>I'm unsure but yes, it probably works because it's a simply a QImage
>under the hoods.


>Read the documentation about connecting signals and slots across threads
>(asynchronous thread connection). What you want is to simply emit a
>signal from the thread (self.emit(SIGNAL("UPDATED_PROGRESS"), value)),
>and connect to that signal from the main thread; in the slot, update the
>The trick is that a signal/slot connection across a thread is different
>from a normal one: in a normal connection, slots are called immediately,
>within the "emit()" call. Instead, in an asynchronous connection, when
>the signal is emitted, an event is posted to the main thread (posting
>events is thread-safe); then the receiving thread's exec loop will
>process the event and call the correct slot.

Ok, I got it! I'll try to implement this...

Thanks again for your help :o)

PS: does it already exist a simple solution to adapt this code:

    thread = threading.Thread(target=func)

using QThread?


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