When you pass the gestaltATSUFeatures selector to the Gestalt function, on return, Gestalt passes back a bit mask which you can use to test for available features in ATSUI.
You can also test the bit mask to determine which version of ATSUI is installed. If any of the bits specified by the mask constants gestaltATSUTrackingFeature, gestaltATSUMemoryFeature, gestaltATSUFallbacksFeature, gestaltATSUGlyphBoundsFeature, gestaltATSULineControlFeature, gestaltATSULayoutCacheClearFeature, or gestaltATSULayoutCreateAndCopyFeature are set, ATSUI 1.1 is installed. If the bit specified by the mask constant gestaltATSUTextLocatorUsageFeature is set, ATSUI 1.2 is installed.
enum {
gestaltATSUTrackingFeature = 0x00000001,
gestaltATSUMemoryFeature = 0x00000001,
gestaltATSUFallbacksFeature = 0x00000001,
gestaltATSUGlyphBoundsFeature = 0x00000001,
gestaltATSULineControlFeature = 0x00000001,
gestaltATSULayoutCacheClearFeature = 0x00000001,
gestaltATSULayoutCreateAndCopyFeature = 0x00000001,
gestaltATSUTextLocatorUsageFeature = 0x00000002
};
If the bit specified by this mask is set, the function ATSUClearLayoutCache is available. Available beginning with ATSUI 1.1.
gestaltATSULayoutCreateAndCopyFeature
If the bit specified by this mask is set, the function ATSUCreateAndCopyTextLayout is available. Available beginning with ATSUI 1.1.
gestaltATSUTextLocatorUsageFeature
If the bit specified by this mask is set, the text break locator attribute is available for both style and text layout objects. Available beginning with ATSUI 1.2.
VERSION NOTES
This enumeration is available beginning with ATSUI 1.1. Additional constants added with ATSUI 1.2.
