How to change font size of chart axis labels?

[Jaguar1]

I am trying to set a different font size (and eventually change also the color) of X and Y axis labels in a chart.
My code is like:

$oShape = $currentSlide->createChartShape(); // ..etc. and chart looks good
$oShape->getPlotArea()->getAxisX()->getFont()->setSize(7); // it does nothing

setSize() doesn't set the new value and font size remains the same. No errors or warnings.

[LilyEssence]

Having the same problem with setting the Axis's Font!

[Progi1984]

@Jaguar1 @LilyEssence Which writer do you use ?

[LilyEssence]

@Jaguar1 @LilyEssence Which writer do you use ?

$oWriterPPTX = IOFactory::createWriter($this->presentation);
file path: vendor/phpoffice/phppresentation/src/PhpPresentation/IOFactory.php

I think it defaults to PowerPoint2007, so that's what we're using.