A wxGraphicsPen is a native representation of a pen. The contents are specific and private to the respective renderer. Instances are ref counted and can therefore be assigned as usual. The only way to get a valid instance is via wxGraphicsContext:createPen/2 or wxGraphicsRenderer::CreatePen() (not implemented in wx).
This class is derived (and can use functions) from: wxGraphicsObject
wxWidgets docs: wxGraphicsPen
wxGraphicsPen() = wx:wx_object()