repaint() on macOS

Perdrix

I've got some long running code that needs to notify the user that it is going to take a while.

Here's what I do:

			if (zgFWHM.empty())
			{
				ZTRACE_RUNTIME("FWHM interpolation");
				message->setText(tr("Interpolating FWHM data.  Please be patient."));
				message->repaint();

				GridData::interpolate(xValues, yValues, fwhmValues, xg, yg, zgFWHM, GridData::InterpolationType::GRID_NNIDW, 10.f);

				message->setText("");
				message->repaint();
				ZTRACE_RUNTIME("FWHM interpolation complete");
			}

This works nicely on Windows and Linux, but on macOS, the message isn't repainted (it's a QLabel).

Is this what I should expect? If not what can I do to ensure the text of the label is updated? Or is it a bug?

Changing the lines that read message->repaint(); to read just repaint(); made no difference.

Oops - forgot to mention: This is Qt 6.10.0

UPDATE:

I did manage to "hack" round the problem by adding:

#if defined(Q_OS_MAC)
				QCoreApplication::processEvents();
#endif

after the first message->repaint();, but I'm pretty sure I shouldn't need to do that!

David

Perdrix

bump ... anyone have ideas about this - is it a bug - if so I will report it.

Christian Ehrlicher

Simply don't block the eventloop...

Perdrix

After a lengthy tussle with QtConcurrent::run() (which is why the delay in responding), I managed to move the long running interpolation code off to another thread.