You can pass a constant of type ATSUFontFallbackMethod to the function ATSUSetFontFallbacks to specify the search options when a character(s) cannot be drawn with the assigned font. The function ATSUGetFontFallbacks passes back one of these constants to indicate the search options you have previously specified.
enum {
kATSUDefaultFontFallbacks = 0,
kATSULastResortOnlyFallback = 1,
kATSUSequentialFallbacksPreferred = 2,
kATSUSequentialFallbacksExclusive = 3
};
typedef UInt16 ATSUFontFallbackMethod;
Constant descriptions
kATSUDefaultFontFallbacks
When a character cannot be drawn with the existing font, specifies that a replacement font should be identified using the following search order: (1) sequentially scanning the font list, and if no valid font is found (2) searching all valid fonts in the user's system. This is the default search order used by the functions ATSUMatchFontsToText and ATSUSetTransientFontMatching.
kATSULastResortOnlyFallback
When a character cannot be drawn with the existing font, specifies that the replacement font should be the last resort font.
kATSUSequentialFallbacksPreferred
When a character cannot be drawn with the existing font, specifies that a replacement font should be identified using the following search order: (1) sequentially scanning the font list, and if no valid font is found (2) searching all valid fonts in the user's system, and if no valid font is found (3) using the last resort font.
kATSUSequentialFallbacksExclusive
When a character cannot be drawn with the existing font, specifies that a replacement font should be identified using the following search order: (1) sequentially scanning the font list, and if no valid font is found (2) using the last resort font.
