NSGlyphInfo object represents a glyph attribute value (
NSGlyphInfoAttributeName) in an attributed string (
NSAttributedString). Glyphs are the graphic representations of characters, stored in a font, that the text system draws on a display or printed page. Before text can be laid out, the layout manager (
NSLayoutManager) generates a stream of glyphs to be laid out, using character and font information specified by the attributed string and contained in the font file.
NSGlyphInfo provides a means to override the standard glyph generation process and substitute a specified glyph over the attribute’s range.
- macOS 10.2+
Glyph attributes are integer values that the layout manager uses to denote special handling for particular glyphs during rendering.
NSGlyphInfo enables you to override a font’s built-in mapping from a Unicode character code to a corresponding glyph ID. Overriding the mapping allows you to specify a variant glyph for a given character if the font contains multiple variations for that character or to specify a glyph that doesn’t have a standard mapping (such as some ligature glyphs).