Unable to add a ImgFace to a node when rendering in memory (%%return)

[Rafiot]

It is currently impossible to add a ImgFace to a node and render the tree, QPixmap will complain with the following warning message:

QPixmap: It is not safe to use pixmaps outside the GUI thread

It is important if you want to display the rendered tree directly in a web page for example.

[Rafiot]

FYI, I solved it this way:

with tempfile.NamedTemporaryFile(suffix='.PNG') as temp:
    img_map = self.tree.render(temp.name, tree_style=self.tree.tree_style)
    temp.seek(0)
    base64_img = base64.b64encode(temp.read())