GI.Gdk.Objects.FrameClock

A GdkFrameClock tells the application when to update and repaint a surface.

This may be synced to the vertical refresh rate of the monitor, for example. Even when the frame clock uses a simple timer rather than a hardware-based vertical sync, the frame clock helps because it ensures everything paints at the same time (reducing the total number of frames).

The frame clock can also automatically stop painting when it knows the frames will not be visible, or scale back animation framerates.

GdkFrameClock is designed to be compatible with an OpenGL-based implementation or with mozRequestAnimationFrame in Firefox, for example.

A frame clock is idle until someone requests a frame with frameClockRequestPhase. At some later point that makes sense for the synchronization being implemented, the clock will process a frame and emit signals for each phase that has been requested. (See the signals of the GdkFrameClock class for documentation of the phases. FrameClockPhaseUpdate and the signalgdkFrameClock[update] signal are most interesting for application writers, and are used to update the animations, using the frame time given by frameClockGetFrameTime.

The frame time is reported in microseconds and generally in the same timescale as getMonotonicTime, however, it is not the same as getMonotonicTime. The frame time does not advance during the time a frame is being painted, and outside of a frame, an attempt is made so that all calls to frameClockGetFrameTime that are called at a “similar” time get the same value. This means that if different animations are timed by looking at the difference in time between an initial value from frameClockGetFrameTime and the value inside the signalgdkFrameClock[update] signal of the clock, they will stay exactly synchronized.

Exported types

newtype FrameClock

Memory-managed wrapper type.

Constructors

FrameClock (ManagedPtr FrameClock)

Instances

Eq FrameClock

Defined in GI.Gdk.Objects.FrameClock

Methods

(==) :: FrameClock -> FrameClock -> Bool

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

GObject FrameClock

Defined in GI.Gdk.Objects.FrameClock

ManagedPtrNewtype FrameClock

Defined in GI.Gdk.Objects.FrameClock

Methods

toManagedPtr :: FrameClock -> ManagedPtr FrameClock

TypedObject FrameClock

Defined in GI.Gdk.Objects.FrameClock

Methods

glibType :: IO GType

HasParentTypes FrameClock

Defined in GI.Gdk.Objects.FrameClock

IsGValue (Maybe FrameClock)

Convert FrameClock to and from GValue. See toGValue and fromGValue.

Defined in GI.Gdk.Objects.FrameClock

Methods

gvalueGType_ :: IO GType

gvalueSet_ :: Ptr GValue -> Maybe FrameClock -> IO ()

gvalueGet_ :: Ptr GValue -> IO (Maybe FrameClock)

type ParentTypes FrameClock

Defined in GI.Gdk.Objects.FrameClock

type ParentTypes FrameClock = '[Object]

class (GObject o, IsDescendantOf FrameClock o) => IsFrameClock o

Type class for types which can be safely cast to FrameClock, for instance with toFrameClock.

Instances

(GObject o, IsDescendantOf FrameClock o) => IsFrameClock o

Defined in GI.Gdk.Objects.FrameClock

toFrameClock :: (MonadIO m, IsFrameClock o) => o -> m FrameClock

Cast to FrameClock, for types for which this is known to be safe. For general casts, use castTo.

Methods

Click to display all available methods, including inherited ones

Methods

beginUpdating, bindProperty, bindPropertyFull, endUpdating, forceFloating, freezeNotify, getv, isFloating, notify, notifyByPspec, ref, refSink, requestPhase, runDispose, stealData, stealQdata, thawNotify, unref, watchClosure.

Getters

getCurrentTimings, getData, getFps, getFrameCounter, getFrameTime, getHistoryStart, getProperty, getQdata, getRefreshInfo, getTimings.

Setters

setData, setDataFull, setProperty.

beginUpdating

frameClockBeginUpdating

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m ()

Starts updates for an animation.

Until a matching call to frameClockEndUpdating is made, the frame clock will continually request a new frame with the FrameClockPhaseUpdate phase. This function may be called multiple times and frames will be requested until frameClockEndUpdating is called the same number of times.

endUpdating

frameClockEndUpdating

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m ()

Stops updates for an animation.

See the documentation for frameClockBeginUpdating.

getCurrentTimings

frameClockGetCurrentTimings

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m (Maybe FrameTimings)

Returns: the GdkFrameTimings for the frame currently being processed, or even no frame is being processed, for the previous frame. Before any frames have been processed, returns Nothing.

Gets the frame timings for the current frame.

getFps

frameClockGetFps

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m Double

Returns: the current fps, as a double

Calculates the current frames-per-second, based on the frame timings of frameClock.

getFrameCounter

frameClockGetFrameCounter

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m Int64

Returns: inside frame processing, the value of the frame counter for the current frame. Outside of frame processing, the frame counter for the last frame.

GdkFrameClock maintains a 64-bit counter that increments for each frame drawn.

getFrameTime

frameClockGetFrameTime

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m Int64

Returns: a timestamp in microseconds, in the timescale of of getMonotonicTime.

Gets the time that should currently be used for animations.

Inside the processing of a frame, it’s the time used to compute the animation position of everything in a frame. Outside of a frame, it's the time of the conceptual “previous frame,” which may be either the actual previous frame time, or if that’s too old, an updated time.

getHistoryStart

frameClockGetHistoryStart

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> m Int64

Returns: the frame counter value for the oldest frame that is available in the internal frame history of the GdkFrameClock

Returns the frame counter for the oldest frame available in history.

GdkFrameClock internally keeps a history of GdkFrameTimings objects for recent frames that can be retrieved with frameClockGetTimings. The set of stored frames is the set from the counter values given by frameClockGetHistoryStart and frameClockGetFrameCounter, inclusive.

getRefreshInfo

frameClockGetRefreshInfo

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> Int64

baseTime: base time for determining a presentaton time

-> m (Int64, Int64)

Predicts a presentation time, based on history.

Using the frame history stored in the frame clock, finds the last known presentation time and refresh interval, and assuming that presentation times are separated by the refresh interval, predicts a presentation time that is a multiple of the refresh interval after the last presentation time, and later than baseTime.

getTimings

frameClockGetTimings

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> Int64

frameCounter: the frame counter value identifying the frame to be received

-> m (Maybe FrameTimings)

Returns: the GdkFrameTimings object for the specified frame, or Nothing if it is not available

Retrieves a GdkFrameTimings object holding timing information for the current frame or a recent frame.

The GdkFrameTimings object may not yet be complete: see frameTimingsGetComplete and frameClockGetHistoryStart.

requestPhase

frameClockRequestPhase

Arguments

:: (HasCallStack, MonadIO m, IsFrameClock a)

=> a

frameClock: a GdkFrameClock

-> [FrameClockPhase]

phase: the phase that is requested

-> m ()

Asks the frame clock to run a particular phase.

The signal corresponding the requested phase will be emitted the next time the frame clock processes. Multiple calls to frameClockRequestPhase will be combined together and only one frame processed. If you are displaying animated content and want to continually request the FrameClockPhaseUpdate phase for a period of time, you should use frameClockBeginUpdating instead, since this allows GTK to adjust system parameters to get maximally smooth animations.

Signals

afterPaint

type FrameClockAfterPaintCallback = IO ()

This signal ends processing of the frame.

Applications should generally not handle this signal.

afterFrameClockAfterPaint :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockAfterPaintCallback) -> m SignalHandlerId

Connect a signal handler for the afterPaint signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #afterPaint callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockAfterPaint :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockAfterPaintCallback) -> m SignalHandlerId

Connect a signal handler for the afterPaint signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #afterPaint callback

beforePaint

type FrameClockBeforePaintCallback = IO ()

Begins processing of the frame.

Applications should generally not handle this signal.

afterFrameClockBeforePaint :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockBeforePaintCallback) -> m SignalHandlerId

Connect a signal handler for the beforePaint signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #beforePaint callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockBeforePaint :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockBeforePaintCallback) -> m SignalHandlerId

Connect a signal handler for the beforePaint signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #beforePaint callback

flushEvents

type FrameClockFlushEventsCallback = IO ()

Used to flush pending motion events that are being batched up and compressed together.

Applications should not handle this signal.

afterFrameClockFlushEvents :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockFlushEventsCallback) -> m SignalHandlerId

Connect a signal handler for the flushEvents signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #flushEvents callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockFlushEvents :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockFlushEventsCallback) -> m SignalHandlerId

Connect a signal handler for the flushEvents signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #flushEvents callback

layout

type FrameClockLayoutCallback = IO ()

Emitted as the second step of toolkit and application processing of the frame.

Any work to update sizes and positions of application elements should be performed. GTK normally handles this internally.

afterFrameClockLayout :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockLayoutCallback) -> m SignalHandlerId

Connect a signal handler for the layout signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #layout callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockLayout :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockLayoutCallback) -> m SignalHandlerId

Connect a signal handler for the layout signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #layout callback

paint

type FrameClockPaintCallback = IO ()

Emitted as the third step of toolkit and application processing of the frame.

The frame is repainted. GDK normally handles this internally and emits Surface::render signals which are turned into Gtk.Widget::snapshot signals by GTK.

afterFrameClockPaint :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockPaintCallback) -> m SignalHandlerId

Connect a signal handler for the paint signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #paint callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockPaint :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockPaintCallback) -> m SignalHandlerId

Connect a signal handler for the paint signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #paint callback

resumeEvents

type FrameClockResumeEventsCallback = IO ()

Emitted after processing of the frame is finished.

This signal is handled internally by GTK to resume normal event processing. Applications should not handle this signal.

afterFrameClockResumeEvents :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockResumeEventsCallback) -> m SignalHandlerId

Connect a signal handler for the resumeEvents signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #resumeEvents callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockResumeEvents :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockResumeEventsCallback) -> m SignalHandlerId

Connect a signal handler for the resumeEvents signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #resumeEvents callback

update

type FrameClockUpdateCallback = IO ()

Emitted as the first step of toolkit and application processing of the frame.

Animations should be updated using frameClockGetFrameTime. Applications can connect directly to this signal, or use Gtk.Widget.add_tick_callback() as a more convenient interface.

afterFrameClockUpdate :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockUpdateCallback) -> m SignalHandlerId

Connect a signal handler for the update signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after frameClock #update callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onFrameClockUpdate :: (IsFrameClock a, MonadIO m) => a -> ((?self :: a) => FrameClockUpdateCallback) -> m SignalHandlerId

Connect a signal handler for the update signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on frameClock #update callback