Classic GUI and threading issue

[stef13013]

Hi,

As I can read, to do the right thing with QT and GUI threading, we have to :
1. Create a new thread (I already have my MainWindow)
2. Compute inside this thread all the "heavy stuff"
3. Then sending a signal to main GUI thread (MainWindow) to do the all rendering/widget update.

Right, but I still don't understand how, in this same main thread, my main window will not freeze If I do important graphics updates

To give you an example :
In the Mandelbrot Qt sample, in the rendering function (updatePixMap()), if I insert a very time consuming code, all the main window still frozen !?
(eg I cannot move my window !?)

Is it possible to avoid this ?

Thanks.

[amleto]

do expensive operations outside of the main thread... It's that simple.

[stef13013]

Not a bad idea, indeed

I wish I could get it just like Delphi does with its thread "Synchronize" method (VCL isn't thread-safe too)

Thanks anyway.

[amleto]

c++11 has simple threads and QThread is pretty simple to use as well.

[wysota]

This is also an almost mandatory lecture with these kinds of questions: [wiki]Keeping the GUI Responsive[/wiki].