A high-priority thread that notifies your app when a given display will need each frame.


A Core Video display link provides a separate high-priority thread to notify your application when a given display will need each frame. You can use a display link to easily synchronize with the refresh rate of a display. The display link API uses the Core Foundation class system internally to provide reference counting behavior and other useful properties.


Inspecting Display Links

func CVDisplayLinkGetCurrentCGDisplay(CVDisplayLink) -> CGDirectDisplayID

Gets the current display associated with a display link.

func CVDisplayLinkGetCurrentTime(CVDisplayLink, UnsafeMutablePointer<CVTimeStamp>) -> CVReturn

Retrieves the current (“now”) time of a given display link.

func CVDisplayLinkTranslateTime(CVDisplayLink, UnsafePointer<CVTimeStamp>, UnsafeMutablePointer<CVTimeStamp>) -> CVReturn

Translates the time in the display link’s time base from one representation to another.

func CVDisplayLinkGetActualOutputVideoRefreshPeriod(CVDisplayLink) -> Double

Retrieves the actual output refresh period of a display as measured by the system time.

func CVDisplayLinkGetNominalOutputVideoRefreshPeriod(CVDisplayLink) -> CVTime

Retrieves the nominal refresh period of a display link.

func CVDisplayLinkGetOutputVideoLatency(CVDisplayLink) -> CVTime

Retrieves the nominal latency of a display link.

func CVDisplayLinkIsRunning(CVDisplayLink) -> Bool

Indicates whether a given display link is running.

func CVDisplayLinkGetTypeID() -> CFTypeID

Obtains the Core Foundation ID for the display link data type.

Managing Display Links

Data Types

class CVDisplayLink

A reference to a display link object.

typealias CVOptionFlags

The flags to be used for the display link output callback function.


typealias CVDisplayLinkOutputCallback

Defines a pointer to a display link output callback function, which is called whenever the display link wants the application to output a frame.

See Also

Time Management


A structure used for storing Core Video time values.