gtk/gdk/gdkframeclock.c
William Jon McCann 469d333aa2 docs: use Returns: consistently
Instead of Return value:
2014-02-19 18:56:05 -05:00

600 lines
19 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* 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;
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: 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: the #GdkFrameTimings for the frame currently being
* processed, or even no frame is being processed, for the
* previous frame. Before any frames have been procesed,
* 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)
{
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;
g_print ("%5" G_GINT64_FORMAT ":", timings->frame_counter);
if (previous_frame_time != 0)
{
g_print (" interval=%-4.1f", (timings->frame_time - previous_frame_time) / 1000.);
g_print (timings->slept_before ? " (sleep)" : " ");
}
if (timings->layout_start_time != 0)
g_print (" layout_start=%-4.1f", (timings->layout_start_time - timings->frame_time) / 1000.);
if (timings->paint_start_time != 0)
g_print (" paint_start=%-4.1f", (timings->paint_start_time - timings->frame_time) / 1000.);
if (timings->frame_end_time != 0)
g_print (" frame_end=%-4.1f", (timings->frame_end_time - timings->frame_time) / 1000.);
if (timings->presentation_time != 0)
g_print (" present=%-4.1f", (timings->presentation_time - timings->frame_time) / 1000.);
if (timings->predicted_presentation_time != 0)
g_print (" predicted=%-4.1f", (timings->predicted_presentation_time - timings->frame_time) / 1000.);
if (timings->refresh_interval != 0)
g_print (" refresh_interval=%-4.1f", timings->refresh_interval / 1000.);
g_print ("\n");
}
#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: 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: 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--;
}
}