The PangoUnderline enumeration is used to specify whether text should be underlined, and if so, the type of underlining.
no underline should be drawn
a single underline should be drawn
a double underline should be drawn
a single underline should be drawn at a position beneath the ink extents of the text being underlined. This should be used only for underlining single characters, such as for keyboard accelerators. PANGO_UNDERLINE_SINGLE should be used for extended portions of text.
a wavy underline should be drawn below. This underline is typically used to indicate an error such as a possilble mispelling; in some cases a contrasting color may automatically be used. This type of underlining is available since Pango 1.4.