Struct gdk::FrameClock [−][src]
pub struct FrameClock(_);
Expand description
A FrameClock
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.
FrameClock
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
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 FrameClock
class for
documentation of the phases. FrameClockPhase::UPDATE
and the
signal::FrameClock::update
signal are most interesting for application
writers, and are used to update the animations, using the frame time
given by 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 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 frame_time()
and the value inside the signal::FrameClock::update
signal of the clock,
they will stay exactly synchronized.
This is an Abstract Base Class, you cannot instantiate it.
Implementations
Starts updates for an animation. Until a matching call to
end_updating()
is made, the frame clock will continually
request a new frame with the FrameClockPhase::UPDATE
phase.
This function may be called multiple times and frames will be
requested until end_updating()
is called the same
number of times.
Stops updates for an animation. See the documentation for
begin_updating()
.
Gets the frame timings for the current frame.
Returns
the FrameTimings
for the
frame currently being processed, or even no frame is being
processed, for the previous frame. Before any frames have been
processed, returns None
.
A FrameClock
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.
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()
.
FrameClock
internally keeps a history of FrameTimings
objects for recent frames that can be retrieved with
timings()
. The set of stored frames
is the set from the counter values given by
history_start()
and
frame_counter()
, inclusive.
Returns
the frame counter value for the oldest frame
that is available in the internal frame history of the
FrameClock
.
Retrieves a FrameTimings
object holding timing information
for the current frame or a recent frame. The FrameTimings
object may not yet be complete: see FrameTimings::is_complete()
.
frame_counter
the frame counter value identifying the frame to be received.
Returns
the FrameTimings
object for
the specified frame, or None
if it is not available. See
history_start()
.
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
request_phase()
will be combined together
and only one frame processed. If you are displaying animated
content and want to continually request the
FrameClockPhase::UPDATE
phase for a period of time,
you should use begin_updating()
instead, since
this allows GTK+ to adjust system parameters to get maximally
smooth animations.
phase
the phase that is requested
This signal ends processing of the frame. Applications should generally not handle this signal.
This signal begins processing of the frame. Applications should generally not handle this signal.
This signal is used to flush pending motion events that are being batched up and compressed together. Applications should not handle this 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.
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.
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.
This signal is emitted as the first step of toolkit and
application processing of the frame. Animations should
be updated using frame_time()
.
Applications can connect directly to this signal, or
use gtk_widget_add_tick_callback()
as a more convenient
interface.
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
.
base_time
base time for determining a presentaton time
Returns
refresh_interval_return
a location to store the
determined refresh interval, or None
. 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.
Trait Implementations
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
Returns the type identifier of Self
.
Auto Trait Implementations
impl RefUnwindSafe for FrameClock
impl !Send for FrameClock
impl !Sync for FrameClock
impl Unpin for FrameClock
impl UnwindSafe for FrameClock
Blanket Implementations
Mutably borrows from an owned value. Read more
Upcasts an object to a superclass or interface T
. Read more
Upcasts an object to a reference of its superclass or interface T
. Read more
Tries to downcast to a subclass or interface implementor T
. Read more
Tries to downcast to a reference of its subclass or interface implementor T
. Read more
Tries to cast to an object of type T
. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast
and upcast
will do many checks at compile-time already. Read more
Tries to cast to reference to an object of type T
. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast
and upcast
will do many checks at compile-time already. Read more
Casts to T
unconditionally. Read more
Casts to &T
unconditionally. Read more
Returns true
if the object is an instance of (can be cast to) T
.
pub fn set_properties_from_value(
&self,
property_values: &[(&str, Value)]
) -> Result<(), BoolError>
pub fn set_property<'a, N, V>(
&self,
property_name: N,
value: V
) -> Result<(), BoolError> where
N: Into<&'a str>,
V: ToValue,
pub fn set_property_from_value<'a, N>(
&self,
property_name: N,
value: &Value
) -> Result<(), BoolError> where
N: Into<&'a str>,
Safety Read more
Safety Read more
Safety Read more
Safety Read more
pub fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec) + Send + Sync,
pub fn connect_notify_local<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec),
pub unsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: Fn(&T, &ParamSpec),
pub fn has_property<'a, N>(&self, property_name: N, type_: Option<Type>) -> bool where
N: Into<&'a str>,
pub fn find_property<'a, N>(&self, property_name: N) -> Option<ParamSpec> where
N: Into<&'a str>,
pub fn connect<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value> + Send + Sync + 'static,
N: Into<&'a str>,
Same as connect
but takes a SignalId
instead of a signal name.
pub fn connect_local<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value> + 'static,
N: Into<&'a str>,
Same as connect_local
but takes a SignalId
instead of a signal name.
pub unsafe fn connect_unsafe<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value>,
N: Into<&'a str>,
Same as connect_unsafe
but takes a SignalId
instead of a signal name.
Emit signal by signal id.
Emit signal with details by signal id.
Emit signal by it’s name.
pub fn bind_property<'a, O, N, M>(
&'a self,
source_property: N,
target: &'a O,
target_property: M
) -> BindingBuilder<'a> where
O: ObjectType,
M: Into<&'a str>,
N: Into<&'a str>,
Same as emit
but takes Value
for the arguments.
Same as emit_by_name
but takes Value
for the arguments.
Returns a SendValue
clone of self
.
impl<'a, T, C> FromValueOptional<'a> for T where
C: ValueTypeChecker<Error = ValueTypeMismatchOrNoneError>,
T: FromValue<'a, Checker = C>,