Sets whether the specified glyphs are not shown.
- macOS 10.4+
trueif the glyphs in
glyphare not shown,
falseif they are shown.
The range of glyphs in question.
For example, a tab or newline character doesn’t leave any marks; it just indicates where following glyphs are laid out.
A subclass can override this method to interact with custom glyph storage.