GI.Gdk.Structs.FrameTimings

A FrameTimings object holds timing information for a single frame of the application’s displays. To retrieve FrameTimings objects, use frameClockGetTimings or frameClockGetCurrentTimings. The information in FrameTimings is useful for precise synchronization of video with the event or audio streams, and for measuring quality metrics for the application’s display, such as latency and jitter.

Exported types

newtype FrameTimings

Memory-managed wrapper type.

Constructors

FrameTimings (ManagedPtr FrameTimings)

Instances

Eq FrameTimings

Defined in GI.Gdk.Structs.FrameTimings

Methods

(==) :: FrameTimings -> FrameTimings -> Bool

(/=) :: FrameTimings -> FrameTimings -> Bool

BoxedObject FrameTimings

Defined in GI.Gdk.Structs.FrameTimings

Methods

boxedType :: FrameTimings -> IO GType

IsGValue FrameTimings

Convert FrameTimings to and from GValue with toGValue and fromGValue.

Defined in GI.Gdk.Structs.FrameTimings

Methods

toGValue :: FrameTimings -> IO GValue

fromGValue :: GValue -> IO FrameTimings

noFrameTimings :: Maybe FrameTimings

A convenience alias for Nothing :: Maybe FrameTimings.

Methods

Overloaded methods

getComplete

frameTimingsGetComplete

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m Bool

Returns: True if all information that will be available for the frame has been filled in.

The timing information in a FrameTimings is filled in incrementally as the frame as drawn and passed off to the window system for processing and display to the user. The accessor functions for FrameTimings can return 0 to indicate an unavailable value for two reasons: either because the information is not yet available, or because it isn't available at all. Once frameTimingsGetComplete returns True for a frame, you can be certain that no further values will become available and be stored in the FrameTimings.

getFrameCounter

frameTimingsGetFrameCounter

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m Int64

Returns: the frame counter value for this frame

Gets the frame counter value of the FrameClock when this this frame was drawn.

getFrameTime

frameTimingsGetFrameTime

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: A FrameTimings

-> m Int64

Returns: the frame time for the frame, in the timescale of getMonotonicTime

Returns the frame time for the frame. This is the time value that is typically used to time animations for the frame. See frameClockGetFrameTime.

getPredictedPresentationTime

frameTimingsGetPredictedPresentationTime

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m Int64

Returns: The predicted time at which the frame will be presented, in the timescale of getMonotonicTime, or 0 if no predicted presentation time is available.

Gets the predicted time at which this frame will be displayed. Although no predicted time may be available, if one is available, it will be available while the frame is being generated, in contrast to frameTimingsGetPresentationTime, which is only available after the frame has been presented. In general, if you are simply animating, you should use frameClockGetFrameTime rather than this function, but this function is useful for applications that want exact control over latency. For example, a movie player may want this information for Audio/Video synchronization.

getPresentationTime

frameTimingsGetPresentationTime

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m Int64

Returns: the time the frame was displayed to the user, in the timescale of getMonotonicTime, or 0 if no presentation time is available. See frameTimingsGetComplete

Reurns the presentation time. This is the time at which the frame became visible to the user.

getRefreshInterval

frameTimingsGetRefreshInterval

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m Int64

Returns: the refresh interval of the display, in microseconds, or 0 if the refresh interval is not available. See frameTimingsGetComplete.

Gets the natural interval between presentation times for the display that this frame was displayed on. Frame presentation usually happens during the “vertical blanking interval”.

ref

frameTimingsRef

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m FrameTimings

Returns: timings

Increases the reference count of timings.

unref

frameTimingsUnref

Arguments

:: (HasCallStack, MonadIO m)

=> FrameTimings

timings: a FrameTimings

-> m ()

Decreases the reference count of timings. If timings is no longer referenced, it will be freed.