kCMTextMarkupAttribute_CharacterBackgroundColorARGB
A background color for individual text characters.
Declaration
let kCMTextMarkupAttribute_CharacterBackgroundColorARGB: CFStringDiscussion
This attribute’s value must be a CFArray of four CFNumbers representing alpha, red, green, and blue fields with values between 0.0 and 1.0. The system interprets the red, green, and blue components in the sRGB color space. The alpha indicates the opacity from 0.0 for transparent to 1.0 for 100 percent opaque.