Mirroring is a property of characters, such as parentheses, whose images are reflected horizontally in text that is laid out right to left. For example, the left parens is the opening parens in left-to-right text, but in right-to-left text the mirrored right parens is the opening parens. The Unicode mirrored property is described in Unicode Standard Annex #9, “The Bidirectional Algorithm”:

RWUCharTraits provides the static method RWUCharTraits::isMirrored(), which returns true if a given RWUChar32 is a code point for a mirrored character. If so, RWUCharTraits::getMirror() returns the code point of the character that provides a “mirror-like” image of a given character; otherwise, it returns the given code point.