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Functions
| GdkFrameTimings * | gdk_frame_timings_ref () |
| void | gdk_frame_timings_unref () |
| gint64 | gdk_frame_timings_get_frame_counter () |
| gboolean | gdk_frame_timings_get_complete () |
| gint64 | gdk_frame_timings_get_frame_time () |
| gint64 | gdk_frame_timings_get_presentation_time () |
| gint64 | gdk_frame_timings_get_refresh_interval () |
| gint64 | gdk_frame_timings_get_predicted_presentation_time () |
Description
A GdkFrameTimings object holds timing information for a single frame
of the application’s displays. To retrieve GdkFrameTimings objects,
use gdk_frame_clock_get_timings() or gdk_frame_clock_get_current_timings().
The information in GdkFrameTimings 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.
Functions
gdk_frame_timings_ref ()
GdkFrameTimings *
gdk_frame_timings_ref (GdkFrameTimings *timings);
Increases the reference count of timings
.
gdk_frame_timings_unref ()
void
gdk_frame_timings_unref (GdkFrameTimings *timings);
Decreases the reference count of timings
. If timings
is no longer referenced, it will be freed.
gdk_frame_timings_get_frame_counter ()
gint64
gdk_frame_timings_get_frame_counter (GdkFrameTimings *timings);
Gets the frame counter value of the GdkFrameClock when this this frame was drawn.
gdk_frame_timings_get_complete ()
gboolean
gdk_frame_timings_get_complete (GdkFrameTimings *timings);
The timing information in a GdkFrameTimings 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 GdkFrameTimings 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 gdk_frame_timings_get_complete() returns
TRUE for a frame, you can be certain that no further values
will become available and be stored in the GdkFrameTimings.
gdk_frame_timings_get_frame_time ()
gint64
gdk_frame_timings_get_frame_time (GdkFrameTimings *timings);
Returns the frame time for the frame. This is the time value
that is typically used to time animations for the frame. See
gdk_frame_clock_get_frame_time().
gdk_frame_timings_get_presentation_time ()
gint64
gdk_frame_timings_get_presentation_time
(GdkFrameTimings *timings);
Reurns the presentation time. This is the time at which the frame became visible to the user.
Returns
the time the frame was displayed to the user, in the
timescale of g_get_monotonic_time(), or 0 if no presentation
time is available. See gdk_frame_timings_get_complete()
gdk_frame_timings_get_refresh_interval ()
gint64
gdk_frame_timings_get_refresh_interval
(GdkFrameTimings *timings);
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”.
Returns
the refresh interval of the display, in microseconds,
or 0 if the refresh interval is not available.
See gdk_frame_timings_get_complete().
gdk_frame_timings_get_predicted_presentation_time ()
gint64
gdk_frame_timings_get_predicted_presentation_time
(GdkFrameTimings *timings);
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
gdk_frame_timings_get_presentation_time(), which is only available
after the frame has been presented. In general, if you are simply
animating, you should use gdk_frame_clock_get_frame_time() 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.