Scene Graph XML: dynamic width of a Label

Is there any way to get the dynamic width of a Label in Scene Graph XML? I’m asked to provide a dynamic focus box around a label and need to know the dynamic width.
Normally I just use roFont.GetOneLineWidth(), but it seems roFont cannot be used in Scene Graph XML. Is there any properties in Label that I can get it’s width or some other approaches?

Sample code would be great helpful. thanks in advance.

Please try using boundingRect() after the label is set.

Regards
Media dev

how can i do that?