Invalidates the cached glyphs for the characters in the given character range, adjusts the character indices of all the subsequent glyphs by the change in length, and invalidates the new character range.
- iOS 7.0+
- macOS 10.0+
- tvOS 9.0+
The range of characters for which to invalidate glyphs.
The number of characters added or removed.
NULL, on output, the actual range invalidated after any necessary expansion. This range can be larger than the range of characters given due to the effect of context on glyphs and layout.
This method only invalidates glyph information and performs no glyph generation or layout. Because invalidating glyphs also invalidates layout, after invoking this method you should also invoke
char as the first argument.
This method is used by the layout mechanism and should be invoked only during typesetting, in almost all cases only by the typesetter. For example, a custom typesetter might invoke it.