kCMTextMarkupAttribute_VerticalLayout
The vertical layout of a text block.
Declaration
let kCMTextMarkupAttribute_VerticalLayout: CFStringDiscussion
Specifying this attribute indicates that the writing direction is vertical instead of horizontal. You can set the associated value to kCMTextVerticalLayout_LeftToRight or kCMTextVerticalLayout_RightToLeft to indicate the progression direction for new vertical lines of text.