Provided by: waylandpp-dev_1.0.0-5ubuntu2_amd64 
NAME
wayland::presentation_feedback_t - presentation time feedback event
SYNOPSIS
#include <wayland-client-protocol-extra.hpp>
Inherits wayland::proxy_t.
Public Types
enum class wrapper_type { standard, display, foreign, proxy_wrapper }
Public Member Functions
std::function< void(output_t)> & on_sync_output ()
presentation synchronized to this output
std::function< void(uint32_t, uint32_t, uint32_t, uint32_t, uint32_t, uint32_t,
presentation_feedback_kind)> & on_presented ()
the content update was displayed
std::function< void()> & on_discarded ()
the content update was not displayed
uint32_t get_id () const
Get the id of a proxy object.
std::string get_class () const
Get the interface name (class) of a proxy object.
uint32_t get_version () const
Get the protocol object version of a proxy object.
wrapper_type get_wrapper_type () const
Get the type of a proxy object.
void set_queue (event_queue_t queue)
Assign a proxy to an event queue.
wl_proxy * c_ptr () const
Get a pointer to the underlying C struct.
bool proxy_has_object () const
Check whether this wrapper actually wraps an object.
operator bool () const
Check whether this wrapper actually wraps an object.
bool operator== (const proxy_t &right) const
Check whether two wrappers refer to the same object.
bool operator!= (const proxy_t &right) const
Check whether two wrappers refer to different objects.
void proxy_release ()
Release the wrapped object (if any), making this an empty wrapper.
Detailed Description
presentation time feedback event
A presentation_feedback object returns an indication that a wl_surface content update has become visible
to the user. One object corresponds to one content update submission (wl_surface.commit). There are two
possible outcomes: the content update is presented to the user, and a presentation timestamp delivered;
or, the user did not see the content update because it was superseded or its surface destroyed, and the
content update is discarded.
Once a presentation_feedback object has delivered a 'presented' or 'discarded' event it is automatically
destroyed.
Definition at line 187 of file wayland-client-protocol-extra.hpp.
Member Enumeration Documentation
enum class wayland::proxy_t::wrapper_type [strong], [inherited]
Underlying wl_proxy type and properties of a proxy_t that affect construction, destruction, and event
handling
Enumerator
standard
C pointer is a standard type compatible with wl_proxy*. Events are dispatched and it is destructed
when the proxy_t is destructed. User data is set.
display
C pointer is a wl_display*. No events are dispatched, wl_display_disconnect is called when the
proxy_t is destructed. User data is set.
foreign
C pointer is a standard type compatible with wl_proxy*, but another library owns it and it should
not be touched in a way that could affect the operation of the other library. No events are
dispatched, wl_proxy_destroy is not called when the proxy_t is destructed, user data is not
touched. Consequently, there is no reference counting for the proxy_t. Lifetime of such wrappers
should preferably be short to minimize the chance that the owning library decides to destroy the
wl_proxy.
proxy_wrapper
C pointer is a wl_proxy* that was constructed with wl_proxy_create_wrapper. No events are
dispatched, wl_proxy_wrapper_destroy is called when the proxy_t is destroyed. Reference counting
is active. A reference to the proxy_t creating this proxy wrapper is held to extend its lifetime
until after the proxy wrapper is destroyed.
Definition at line 116 of file wayland-client.hpp.
Member Function Documentation
wl_proxy * wayland::proxy_t::c_ptr () const [inherited]
Get a pointer to the underlying C struct.
Returns
The underlying wl_proxy wrapped by this proxy_t if it exists, otherwise an exception is thrown
std::string wayland::proxy_t::get_class () const [inherited]
Get the interface name (class) of a proxy object.
Returns
The interface name of the object associated with the proxy
uint32_t wayland::proxy_t::get_id () const [inherited]
Get the id of a proxy object.
Returns
The id the object associated with the proxy
uint32_t wayland::proxy_t::get_version () const [inherited]
Get the protocol object version of a proxy object. Gets the protocol object version of a proxy object, or
0 if the proxy was created with unversioned API.
A returned value of 0 means that no version information is available, so the caller must make safe
assumptions about the object's real version.
display_t will always return version 0.
Returns
The protocol object version of the proxy or 0
wrapper_type wayland::proxy_t::get_wrapper_type () const [inline], [inherited]
Get the type of a proxy object.
Definition at line 302 of file wayland-client.hpp.
std::function< void()> & presentation_feedback_t::on_discarded ()
the content update was not displayed The content update was never displayed to the user.
Definition at line 804 of file wayland-client-protocol-extra.cpp.
std::function< void(uint32_t, uint32_t, uint32_t, uint32_t, uint32_t, uint32_t, presentation_feedback_kind)>
& presentation_feedback_t::on_presented ()
the content update was displayed
Parameters
tv_sec_hi high 32 bits of the seconds part of the presentation timestamp
tv_sec_lo low 32 bits of the seconds part of the presentation timestamp
tv_nsec nanoseconds part of the presentation timestamp
refresh nanoseconds till next refresh
seq_hi high 32 bits of refresh counter
seq_lo low 32 bits of refresh counter
flags combination of 'kind' values
The associated content update was displayed to the user at the indicated time (tv_sec_hi/lo, tv_nsec).
For the interpretation of the timestamp, see presentation.clock_id event.
The timestamp corresponds to the time when the content update turned into light the first time on the
surface's main output. Compositors may approximate this from the framebuffer flip completion events from
the system, and the latency of the physical display path if known.
This event is preceded by all related sync_output events telling which output's refresh cycle the
feedback corresponds to, i.e. the main output for the surface. Compositors are recommended to choose the
output containing the largest part of the wl_surface, or keeping the output they previously chose. Having
a stable presentation output association helps clients predict future output refreshes (vblank).
The 'refresh' argument gives the compositor's prediction of how many nanoseconds after tv_sec, tv_nsec
the very next output refresh may occur. This is to further aid clients in predicting future refreshes,
i.e., estimating the timestamps targeting the next few vblanks. If such prediction cannot usefully be
done, the argument is zero.
If the output does not have a constant refresh rate, explicit video mode switches excluded, then the
refresh argument must be zero.
The 64-bit value combined from seq_hi and seq_lo is the value of the output's vertical retrace counter
when the content update was first scanned out to the display. This value must be compatible with the
definition of MSC in GLX_OML_sync_control specification. Note, that if the display path has a non-zero
latency, the time instant specified by this counter may differ from the timestamp's.
If the output does not have a concept of vertical retrace or a refresh cycle, or the output device is
self-refreshing without a way to query the refresh count, then the arguments seq_hi and seq_lo must be
zero.
Definition at line 799 of file wayland-client-protocol-extra.cpp.
std::function< void(output_t)> & presentation_feedback_t::on_sync_output ()
presentation synchronized to this output
Parameters
output presentation output
As presentation can be synchronized to only one output at a time, this event tells which output it was.
This event is only sent prior to the presented event.
As clients may bind to the same global wl_output multiple times, this event is sent for each bound
instance that matches the synchronized output. If a client has not bound to the right wl_output global at
all, this event is not sent.
Definition at line 794 of file wayland-client-protocol-extra.cpp.
wayland::proxy_t::operator bool () const [inherited]
Check whether this wrapper actually wraps an object.
Returns
true if there is an underlying object, false if this wrapper is empty
bool wayland::proxy_t::operator!= (const proxy_t & right) const [inherited]
Check whether two wrappers refer to different objects.
bool wayland::proxy_t::operator== (const proxy_t & right) const [inherited]
Check whether two wrappers refer to the same object.
bool wayland::proxy_t::proxy_has_object () const [inherited]
Check whether this wrapper actually wraps an object.
Returns
true if there is an underlying object, false if this wrapper is empty
void wayland::proxy_t::proxy_release () [inherited]
Release the wrapped object (if any), making this an empty wrapper. Note that display_t instances cannot
be released this way. Attempts to do so are ignored.
Examples
foreign_display.cpp.
void wayland::proxy_t::set_queue (event_queue_t queue) [inherited]
Assign a proxy to an event queue.
Parameters
queue The event queue that will handle this proxy
Assign proxy to event queue. Events coming from proxy will be queued in queue instead of the display's
main queue.
See also: display_t::dispatch_queue().
Examples
proxy_wrapper.cpp.
Author
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Version 1.0.0 Mon Apr 22 2024 09:52:15 wayland::presentation_feedback_t(3)