gtk2/gdk/gdkframeclock.c

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/* GDK - The GIMP Drawing Kit
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GTK+ Team and others 1997-2010. See the AUTHORS
* file for a list of people on the GTK+ Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "gdkframeclockprivate.h"
#include "gdkinternals.h"
/**
* SECTION:gdkframeclock
* @Short_description: Frame clock syncs painting to a window or display
* @Title: Frame clock
*
* A #GdkFrameClock tells the application when to update and repaint a
* window. 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
* gdk_frame_clock_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
* #GdkFrameClock::update signal are most interesting for application
* writers, and are used to update the animations, using the frame time
* given by gdk_frame_clock_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 gdk_frame_clock_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 gdk_frame_clock_get_frame_time()
* and the value inside the #GdkFrameClock::update signal of the clock,
* they will stay exactly synchronized.
*/
enum {
FLUSH_EVENTS,
BEFORE_PAINT,
UPDATE,
LAYOUT,
PAINT,
AFTER_PAINT,
RESUME_EVENTS,
LAST_SIGNAL
};
static guint signals[LAST_SIGNAL];
#define FRAME_HISTORY_MAX_LENGTH 16
struct _GdkFrameClockPrivate
{
gint64 frame_counter;
gint n_timings;
gint current;
GdkFrameTimings *timings[FRAME_HISTORY_MAX_LENGTH];
};
G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GdkFrameClock, gdk_frame_clock, G_TYPE_OBJECT)
static void
gdk_frame_clock_finalize (GObject *object)
{
GdkFrameClockPrivate *priv = GDK_FRAME_CLOCK (object)->priv;
int i;
for (i = 0; i < FRAME_HISTORY_MAX_LENGTH; i++)
if (priv->timings[i] != 0)
gdk_frame_timings_unref (priv->timings[i]);
G_OBJECT_CLASS (gdk_frame_clock_parent_class)->finalize (object);
}
static void
gdk_frame_clock_class_init (GdkFrameClockClass *klass)
{
GObjectClass *gobject_class = (GObjectClass*) klass;
gobject_class->finalize = gdk_frame_clock_finalize;
/**
* GdkFrameClock::flush-events:
* @clock: the frame clock emitting the signal
*
* This signal is used to flush pending motion events that
* are being batched up and compressed together. Applications
* should not handle this signal.
*/
signals[FLUSH_EVENTS] =
g_signal_new (g_intern_static_string ("flush-events"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GdkFrameClock::before-paint:
* @clock: the frame clock emitting the signal
*
* This signal begins processing of the frame. Applications
* should generally not handle this signal.
*/
signals[BEFORE_PAINT] =
g_signal_new (g_intern_static_string ("before-paint"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GdkFrameClock::update:
* @clock: the frame clock emitting the signal
*
* This signal is emitted as the first step of toolkit and
* application processing of the frame. Animations should
* be updated using gdk_frame_clock_get_frame_time().
* Applications can connect directly to this signal, or
* use gtk_widget_add_tick_callback() as a more convenient
* interface.
*/
signals[UPDATE] =
g_signal_new (g_intern_static_string ("update"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GdkFrameClock::layout:
* @clock: the frame clock emitting the signal
*
* This signal is 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.
*/
signals[LAYOUT] =
g_signal_new (g_intern_static_string ("layout"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GdkFrameClock::paint:
* @clock: the frame clock emitting the signal
*
* This signal is emitted as the third step of toolkit and
* application processing of the frame. The frame is
* repainted. GDK normally handles this internally and
* produces expose events, which are turned into GTK+
* #GtkWidget::draw signals.
*/
signals[PAINT] =
g_signal_new (g_intern_static_string ("paint"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GdkFrameClock::after-paint:
* @clock: the frame clock emitting the signal
*
* This signal ends processing of the frame. Applications
* should generally not handle this signal.
*/
signals[AFTER_PAINT] =
g_signal_new (g_intern_static_string ("after-paint"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GdkFrameClock::resume-events:
* @clock: the frame clock emitting the signal
*
* This signal is emitted after processing of the frame is
* finished, and is handled internally by GTK+ to resume normal
* event processing. Applications should not handle this signal.
*/
signals[RESUME_EVENTS] =
g_signal_new (g_intern_static_string ("resume-events"),
GDK_TYPE_FRAME_CLOCK,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE, 0);
}
static void
gdk_frame_clock_init (GdkFrameClock *clock)
{
GdkFrameClockPrivate *priv;
clock->priv = priv = gdk_frame_clock_get_instance_private (clock);
priv->frame_counter = -1;
priv->current = FRAME_HISTORY_MAX_LENGTH - 1;
}
/**
* gdk_frame_clock_get_frame_time:
* @frame_clock: a #GdkFrameClock
*
* Gets the time that should currently be used for animations. Inside
* the processing of a frame, its 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 thats too old, an updated
* time.
*
* Since: 3.8
* Returns: a timestamp in microseconds, in the timescale of
* of g_get_monotonic_time().
*/
gint64
gdk_frame_clock_get_frame_time (GdkFrameClock *frame_clock)
{
g_return_val_if_fail (GDK_IS_FRAME_CLOCK (frame_clock), 0);
return GDK_FRAME_CLOCK_GET_CLASS (frame_clock)->get_frame_time (frame_clock);
}
/**
* gdk_frame_clock_request_phase:
* @frame_clock: a #GdkFrameClock
* @phase: the phase that is requested
*
* 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 gdk_frame_clock_begin_updating() instead, since
* this allows GTK+ to adjust system parameters to get maximally
* smooth animations.
*
* Since: 3.8
*/
void
gdk_frame_clock_request_phase (GdkFrameClock *frame_clock,
GdkFrameClockPhase phase)
{
g_return_if_fail (GDK_IS_FRAME_CLOCK (frame_clock));
GDK_FRAME_CLOCK_GET_CLASS (frame_clock)->request_phase (frame_clock, phase);
}
/**
* gdk_frame_clock_begin_updating:
* @frame_clock: a #GdkFrameClock
*
* Starts updates for an animation. Until a matching call to
* gdk_frame_clock_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.
*
* Since: 3.8
*/
void
gdk_frame_clock_begin_updating (GdkFrameClock *frame_clock)
{
g_return_if_fail (GDK_IS_FRAME_CLOCK (frame_clock));
GDK_FRAME_CLOCK_GET_CLASS (frame_clock)->begin_updating (frame_clock);
}
/**
* gdk_frame_clock_end_updating:
* @frame_clock: a #GdkFrameClock
*
* Stops updates for an animation. See the documentation for
* gdk_frame_clock_begin_updating().
*
* Since: 3.8
*/
void
gdk_frame_clock_end_updating (GdkFrameClock *frame_clock)
{
g_return_if_fail (GDK_IS_FRAME_CLOCK (frame_clock));
GDK_FRAME_CLOCK_GET_CLASS (frame_clock)->end_updating (frame_clock);
}
void
_gdk_frame_clock_freeze (GdkFrameClock *clock)
{
g_return_if_fail (GDK_IS_FRAME_CLOCK (clock));
GDK_FRAME_CLOCK_GET_CLASS (clock)->freeze (clock);
}
void
_gdk_frame_clock_thaw (GdkFrameClock *clock)
{
g_return_if_fail (GDK_IS_FRAME_CLOCK (clock));
GDK_FRAME_CLOCK_GET_CLASS (clock)->thaw (clock);
}
/**
* gdk_frame_clock_get_frame_counter:
* @frame_clock: a #GdkFrameClock
*
* A #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.
* Since: 3.8
*/
gint64
gdk_frame_clock_get_frame_counter (GdkFrameClock *frame_clock)
{
GdkFrameClockPrivate *priv;
g_return_val_if_fail (GDK_IS_FRAME_CLOCK (frame_clock), 0);
priv = frame_clock->priv;
return priv->frame_counter;
}
/**
* gdk_frame_clock_get_history_start:
* @frame_clock: a #GdkFrameClock
*
* #GdkFrameClock internally keeps a history of #GdkFrameTimings
* objects for recent frames that can be retrieved with
* gdk_frame_clock_get_timings(). The set of stored frames
* is the set from the counter values given by
* gdk_frame_clock_get_history_start() and
* gdk_frame_clock_get_frame_counter(), inclusive.
*
* Returns: the frame counter value for the oldest frame
* that is available in the internal frame history of the
* #GdkFrameClock.
* Since: 3.8
*/
gint64
gdk_frame_clock_get_history_start (GdkFrameClock *frame_clock)
{
GdkFrameClockPrivate *priv;
g_return_val_if_fail (GDK_IS_FRAME_CLOCK (frame_clock), 0);
priv = frame_clock->priv;
return priv->frame_counter + 1 - priv->n_timings;
}
void
_gdk_frame_clock_begin_frame (GdkFrameClock *frame_clock)
{
GdkFrameClockPrivate *priv;
g_return_if_fail (GDK_IS_FRAME_CLOCK (frame_clock));
priv = frame_clock->priv;
priv->frame_counter++;
priv->current = (priv->current + 1) % FRAME_HISTORY_MAX_LENGTH;
/* Try to steal the previous frame timing instead of discarding
* and allocating a new one.
*/
if G_LIKELY (priv->n_timings == FRAME_HISTORY_MAX_LENGTH &&
_gdk_frame_timings_steal (priv->timings[priv->current],
priv->frame_counter))
return;
if (priv->n_timings < FRAME_HISTORY_MAX_LENGTH)
priv->n_timings++;
else
gdk_frame_timings_unref (priv->timings[priv->current]);
priv->timings[priv->current] = _gdk_frame_timings_new (priv->frame_counter);
}
/**
* gdk_frame_clock_get_timings:
* @frame_clock: a #GdkFrameClock
* @frame_counter: the frame counter value identifying the frame to
* be received.
*
* Retrieves a #GdkFrameTimings object holding timing information
* for the current frame or a recent frame. The #GdkFrameTimings
* object may not yet be complete: see gdk_frame_timings_get_complete().
*
* Returns: (nullable): the #GdkFrameTimings object for the specified
* frame, or %NULL if it is not available. See
* gdk_frame_clock_get_history_start().
* Since: 3.8
*/
GdkFrameTimings *
gdk_frame_clock_get_timings (GdkFrameClock *frame_clock,
gint64 frame_counter)
{
GdkFrameClockPrivate *priv;
gint pos;
g_return_val_if_fail (GDK_IS_FRAME_CLOCK (frame_clock), NULL);
priv = frame_clock->priv;
if (frame_counter > priv->frame_counter)
return NULL;
if (frame_counter <= priv->frame_counter - priv->n_timings)
return NULL;
pos = (priv->current - (priv->frame_counter - frame_counter) + FRAME_HISTORY_MAX_LENGTH) % FRAME_HISTORY_MAX_LENGTH;
return priv->timings[pos];
}
/**
* gdk_frame_clock_get_current_timings:
* @frame_clock: a #GdkFrameClock
*
* Gets the frame timings for the current frame.
*
* Returns: (nullable): 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.
* Since: 3.8
*/
GdkFrameTimings *
gdk_frame_clock_get_current_timings (GdkFrameClock *frame_clock)
{
GdkFrameClockPrivate *priv;
g_return_val_if_fail (GDK_IS_FRAME_CLOCK (frame_clock), 0);
priv = frame_clock->priv;
return gdk_frame_clock_get_timings (frame_clock, priv->frame_counter);
}
#ifdef G_ENABLE_DEBUG
void
_gdk_frame_clock_debug_print_timings (GdkFrameClock *clock,
GdkFrameTimings *timings)
{
GString *str;
gint64 previous_frame_time = 0;
GdkFrameTimings *previous_timings = gdk_frame_clock_get_timings (clock,
timings->frame_counter - 1);
if (previous_timings != NULL)
previous_frame_time = previous_timings->frame_time;
str = g_string_new ("");
g_string_append_printf (str, "%5" G_GINT64_FORMAT ":", timings->frame_counter);
if (previous_frame_time != 0)
{
g_string_append_printf (str, " interval=%-4.1f", (timings->frame_time - previous_frame_time) / 1000.);
g_string_append_printf (str, timings->slept_before ? " (sleep)" : " ");
}
if (timings->layout_start_time != 0)
g_string_append_printf (str, " layout_start=%-4.1f", (timings->layout_start_time - timings->frame_time) / 1000.);
if (timings->paint_start_time != 0)
g_string_append_printf (str, " paint_start=%-4.1f", (timings->paint_start_time - timings->frame_time) / 1000.);
if (timings->frame_end_time != 0)
g_string_append_printf (str, " frame_end=%-4.1f", (timings->frame_end_time - timings->frame_time) / 1000.);
if (timings->presentation_time != 0)
g_string_append_printf (str, " present=%-4.1f", (timings->presentation_time - timings->frame_time) / 1000.);
if (timings->predicted_presentation_time != 0)
g_string_append_printf (str, " predicted=%-4.1f", (timings->predicted_presentation_time - timings->frame_time) / 1000.);
if (timings->refresh_interval != 0)
g_string_append_printf (str, " refresh_interval=%-4.1f", timings->refresh_interval / 1000.);
g_message ("%s", str->str);
g_string_free (str, TRUE);
}
#endif /* G_ENABLE_DEBUG */
#define DEFAULT_REFRESH_INTERVAL 16667 /* 16.7ms (1/60th second) */
#define MAX_HISTORY_AGE 150000 /* 150ms */
/**
* gdk_frame_clock_get_refresh_info:
* @frame_clock: a #GdkFrameClock
* @base_time: base time for determining a presentaton time
* @refresh_interval_return: (out) (optional): a location to store the
* determined refresh interval, or %NULL. A default refresh interval of
* 1/60th of a second will be stored if no history is present.
* @presentation_time_return: (out): a location to store the next
* candidate presentation time after the given base time.
* 0 will be will be stored if no history is present.
*
* 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 @base_time.
*
* Since: 3.8
*/
void
gdk_frame_clock_get_refresh_info (GdkFrameClock *frame_clock,
gint64 base_time,
gint64 *refresh_interval_return,
gint64 *presentation_time_return)
{
gint64 frame_counter;
g_return_if_fail (GDK_IS_FRAME_CLOCK (frame_clock));
frame_counter = gdk_frame_clock_get_frame_counter (frame_clock);
if (presentation_time_return)
*presentation_time_return = 0;
if (refresh_interval_return)
*refresh_interval_return = DEFAULT_REFRESH_INTERVAL;
while (TRUE)
{
GdkFrameTimings *timings = gdk_frame_clock_get_timings (frame_clock, frame_counter);
gint64 presentation_time;
gint64 refresh_interval;
if (timings == NULL)
return;
refresh_interval = timings->refresh_interval;
presentation_time = timings->presentation_time;
if (presentation_time != 0)
{
if (presentation_time > base_time - MAX_HISTORY_AGE &&
presentation_time_return)
{
if (refresh_interval == 0)
refresh_interval = DEFAULT_REFRESH_INTERVAL;
if (refresh_interval_return)
*refresh_interval_return = refresh_interval;
while (presentation_time < base_time)
presentation_time += refresh_interval;
if (presentation_time_return)
*presentation_time_return = presentation_time;
}
return;
}
frame_counter--;
}
}
void
_gdk_frame_clock_emit_flush_events (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[FLUSH_EVENTS], 0);
}
void
_gdk_frame_clock_emit_before_paint (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[BEFORE_PAINT], 0);
}
void
_gdk_frame_clock_emit_update (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[UPDATE], 0);
}
void
_gdk_frame_clock_emit_layout (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[LAYOUT], 0);
}
void
_gdk_frame_clock_emit_paint (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[PAINT], 0);
}
void
_gdk_frame_clock_emit_after_paint (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[AFTER_PAINT], 0);
}
void
_gdk_frame_clock_emit_resume_events (GdkFrameClock *frame_clock)
{
g_signal_emit (frame_clock, signals[RESUME_EVENTS], 0);
}