Currently, In ImageGear Professional for C & C++, there is no attribute to add to font objects such as HDE_PDE_FONT to give them underline or strikethrough effects which correspond to the thickness of the lettering.
A catch-all solution can be made by drawing the line onto the page/image as a proportion of the bounding box surrounding the font, but the thickness of this line may not always match the font, and this is noticeable when two different fonts are placed side by side.
As a customer, I would like to be able to add underline/strikethrough to text which matches the lettering & size of the font it's being applied to.
I have attached a picture of this proposed functionality in Microsoft Word, where I've taken two fonts with drastically different thickness in lettering (Arial and Franklin Gothic Heavy) at Pt 60, and underlined them both. They have noticeably different underline thicknesses. It is worth mentioning that Microsoft Word does not do this for strikethrough, and LibreOffice does not do this for either.