The XmNlayoutModifier affects the layout behavior of the text associated with the XmRendition. For example, if the layout default treatment of numerals is NUMERALS_NOMINAL, you change to NUMERALS_NATIONAL by setting XmNlayoutModifier to @ls numerals=nominal:national, or @ls numerals=:national.
Encoding description – TypeOfText, TextShaping, ShapeCharset (and locale codeset)
TypeOfText is essentially segment ordering and can be illustrated with opaque blocks. Modifying these values dynamically through the rendition object is not usually meaningful, and is almost certain to result in unpredictable behavior.
Layout behavior – Orientation, Context, ImplicitAlg, Swapping, and Numerals. Orientation and Context should not be modified dynamically. You can safely modify ImplicitAlg, Swapping, and Numerals.
Editing behavior – CheckMode