Class FrameClock

All Implemented Interfaces:
PointerInterface

public class FrameClock extends Object
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
[method@Gdk.FrameClock.request_phase]. 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.
%GDK_FRAME_CLOCK_PHASE_UPDATE and the [signal@GdkFrameClock::update] signal
are most interesting for application writers, and are used to update the
animations, using the frame time given by [method@Gdk.FrameClock.get_frame_time].

The frame time is reported in microseconds and generally in the same
timescale as g_get_monotonic_time(), however, it is not the same
as g_get_monotonic_time(). 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 [method@Gdk.FrameClock.get_frame_time] 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 [method@Gdk.FrameClock.get_frame_time]
and the value inside the [signal@GdkFrameClock::update] signal of the clock,
they will stay exactly synchronized.

https://docs.gtk.org/gdk4/class.FrameClock.html

  • Field Details

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()
    • beginUpdating

      public void beginUpdating()
      Starts updates for an animation.

      Until a matching call to [method@Gdk.FrameClock.end_updating] is made,
      the frame clock will continually request a new frame with the
      %GDK_FRAME_CLOCK_PHASE_UPDATE phase. This function may be called multiple
      times and frames will be requested until gdk_frame_clock_end_updating()
      is called the same number of times.
    • endUpdating

      public void endUpdating()
      Stops updates for an animation.

      See the documentation for [method@Gdk.FrameClock.begin_updating].
    • getCurrentTimings

      public FrameTimings getCurrentTimings()
      Gets the frame timings for the current frame.
      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 %NULL.
    • getFps

      public double getFps()
      Calculates the current frames-per-second, based on the
      frame timings of @frame_clock.
      Returns:
      the current fps, as a `double`
    • getFrameCounter

      public long getFrameCounter()
      `GdkFrameClock` maintains a 64-bit counter that increments for
      each frame drawn.
      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.
    • getFrameTime

      public long getFrameTime()
      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.
      Returns:
      a timestamp in microseconds, in the timescale of of g_get_monotonic_time().
    • getHistoryStart

      public long getHistoryStart()
      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
      [method@Gdk.FrameClock.get_timings]. The set of stored frames
      is the set from the counter values given by
      [method@Gdk.FrameClock.get_history_start] and
      [method@Gdk.FrameClock.get_frame_counter], inclusive.
      Returns:
      the frame counter value for the oldest frame that is available in the internal frame history of the `GdkFrameClock`
    • getTimings

      public FrameTimings getTimings(long frame_counter)
      Retrieves a `GdkFrameTimings` object holding timing information
      for the current frame or a recent frame.

      The `GdkFrameTimings` object may not yet be complete: see
      [method@Gdk.FrameTimings.get_complete] and
      [method@Gdk.FrameClock.get_history_start].
      Parameters:
      frame_counter - the frame counter value identifying the frame to be received
      Returns:
      the `GdkFrameTimings` object for the specified frame, or %NULL if it is not available
    • requestPhase

      public void requestPhase(int phase)
      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
      gdk_frame_clock_request_phase() will be combined together
      and only one frame processed. If you are displaying animated
      content and want to continually request the
      %GDK_FRAME_CLOCK_PHASE_UPDATE phase for a period of time,
      you should use [method@Gdk.FrameClock.begin_updating] instead,
      since this allows GTK to adjust system parameters to get maximally
      smooth animations.
      Parameters:
      phase - the phase that is requested
    • onAfterPaint

      public SignalHandler onAfterPaint(FrameClock.OnAfterPaint signal)
      Connect to signal "after-paint".
      See FrameClock.OnAfterPaint.onAfterPaint() for signal description.
      Field SIGNAL_ON_AFTER_PAINT contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • onBeforePaint

      public SignalHandler onBeforePaint(FrameClock.OnBeforePaint signal)
      Connect to signal "before-paint".
      See FrameClock.OnBeforePaint.onBeforePaint() for signal description.
      Field SIGNAL_ON_BEFORE_PAINT contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • onFlushEvents

      public SignalHandler onFlushEvents(FrameClock.OnFlushEvents signal)
      Connect to signal "flush-events".
      See FrameClock.OnFlushEvents.onFlushEvents() for signal description.
      Field SIGNAL_ON_FLUSH_EVENTS contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • onLayout

      public SignalHandler onLayout(FrameClock.OnLayout signal)
      Connect to signal "layout".
      See FrameClock.OnLayout.onLayout() for signal description.
      Field SIGNAL_ON_LAYOUT contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • onPaint

      public SignalHandler onPaint(FrameClock.OnPaint signal)
      Connect to signal "paint".
      See FrameClock.OnPaint.onPaint() for signal description.
      Field SIGNAL_ON_PAINT contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • onResumeEvents

      public SignalHandler onResumeEvents(FrameClock.OnResumeEvents signal)
      Connect to signal "resume-events".
      See FrameClock.OnResumeEvents.onResumeEvents() for signal description.
      Field SIGNAL_ON_RESUME_EVENTS contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • onUpdate

      public SignalHandler onUpdate(FrameClock.OnUpdate signal)
      Connect to signal "update".
      See FrameClock.OnUpdate.onUpdate() for signal description.
      Field SIGNAL_ON_UPDATE contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • getTypeID

      public static long getTypeID()
    • getParentTypeID

      public static long getParentTypeID()
    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()
    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()
    • getInstanceSize

      public static int getInstanceSize()