I want to show the relationship between two edges, and I use AIS_TextLabel to achieve this function. For example, there are two parallel edges, I use the code below, however, it doesn't work. I know it should be converted to a unicode string, and I can show it on the widget made by Qt.
Standard_CString str= "∥";
Handle(AIS_TextLabel) aLabel = new AIS_TextLabel();
aLabel -> SetText(extstr);
aLabel -> SetColor(Quantity_NOC_RED);
aLabel -> SetFont("Arial");