Defines the event system that wraps the Starboard main loop and entry point.
The Starboard Application Lifecycle
---------- * | | | Preload | | | V Start [ PRELOADING ] ------------ | | | | Start | | | | | V | ----> [ STARTED ] <---- | | | | Pause Unpause | | | Suspend V | | -----> [ PAUSED ] ----- | | | | Resume Suspend | | | | | V | ---- [ SUSPENDED ] <------------ | Stop | V [ STOPPED ]
The first event that a Starboard application receives is either
Start puts the
application in the
STARTED state, whereas
Preload puts the application in
PRELOADING can only happen as the first application state. In this state, the
application should start and run as normal, but will not receive any input, and
should not try to initialize graphics resources (via GL or
PRELOADING, the application can receive
will receive the same data that was passed into
STARTED state, the application is in the foreground and can expect to
do all of the normal things it might want to do. Once in the
STARTED state, it
may receive a
Pause event, putting the application into the
PAUSED state, the application is still visible, but has lost focus, or
it is partially obscured by a modal dialog, or it is on its way to being shut
down. The application should pause activity in this state. In this state, it can
Unpause to be brought back to the foreground state (
Suspend to be pushed further in the background to the
SUSPENDED state, the application is generally not visible. It should
immediately release all graphics and video resources, and shut down all
background activity (timers, rendering, etc). Additionally, the application
should flush storage to ensure that if the application is killed, the storage
will be up-to-date. The application may be killed at this point, but will
ideally receive a
Stop event for a more graceful shutdown.
Note that the application is always expected to transition through
SUSPENDED before receiving
Stop or being killed.
An enumeration of all possible event types dispatched directly by the system. Each event is accompanied by a void* data argument, and each event must define the type of the value pointed to by that data argument, if any.
Applications should perform initialization and prepare to react to subsequent events, but must not initialize any graphics resources (through GL or SbBlitter). The intent of this event is to allow the application to do as much work as possible ahead of time, so that when the application is first brought to the foreground, it's as fast as a resume.
kSbEventTypeStartevent may be sent at any time, regardless of initialization state. Input events will not be sent in the
PRELOADINGstate. This event will only be sent once for a given process launch. SbEventStartData is passed as the data argument.
The system may send
PRELOADINGif it wants to push the app into a lower resource consumption state. Applications can alo call SbSystemRequestSuspend() when they are done preloading to request this.
The first event that an application receives on startup when starting normally (i.e. not being preloaded). Applications should perform initialization, start running, and prepare to react to subsequent events. Applications that wish to run and then exit must call
SbSystemRequestStop()to terminate. This event will only be sent once for a given process launch.
SbEventStartDatais passed as the data argument. In case of preload, the
SbEventStartDatawill be the same as what was passed to
A dialog will be raised or the application will otherwise be put into a background-but-visible or partially-obscured state (PAUSED). Graphics and video resources will still be available, but the application should pause foreground activity like animations and video playback. Can only be received after a Start event. The only events that should be dispatched after a Pause event are Unpause or Suspend. No data argument.
The application is returning to the foreground (STARTED) after having been put in the PAUSED (e.g. partially-obscured) state. The application should unpause foreground activity like animations and video playback. Can only be received after a Pause or Resume event. No data argument.
The operating system will put the application into a Suspended state after this event is handled. The application is expected to stop periodic background work, release ALL graphics and video resources, and flush any pending SbStorage writes. Some platforms will terminate the application if work is done or resources are retained after suspension. Can only be received after a Pause event. The only events that should be dispatched after a Suspend event are Resume or Stop. On some platforms, the process may also be killed after Suspend without a Stop event. No data argument.
The operating system has restored the application to the PAUSED state from the SUSPENDED state. This is the first event the application will receive coming out of SUSPENDED, and it will only be received after a Suspend event. The application will now be in the PAUSED state. No data argument.
The operating system will shut the application down entirely after this event is handled. Can only be recieved after a Suspend event, in the SUSPENDED state. No data argument.
A user input event, including keyboard, mouse, gesture, or something else. SbInputData (from input.h) is passed as the data argument.
A user change event, which means a new user signed-in or signed-out, or the current user changed. No data argument, call SbUserGetSignedIn() and SbUserGetCurrent() to get the latest changes.
A navigational link has come from the system, and the application should consider handling it by navigating to the corresponding application location. The data argument is an application-specific, null-terminated string.
The beginning of a vertical sync has been detected. This event is very timing-sensitive, so as little work as possible should be done on the main thread if the application wants to receive this event in a timely manner. No data argument.
An event type reserved for scheduled callbacks. It will only be sent in response to an application call to SbEventSchedule(), and it will call the callback directly, so SbEventHandle should never receive this event directly. The data type is an internally-defined structure.
The platform's accessibility settings have changed. The application should query the accessibility settings using the appropriate APIs to get the new settings. Note this excludes captions settings changes, which causes kSbEventTypeAccessibilityCaptionSettingsChanged to fire. If the starboard version has kSbEventTypeAccessiblityTextToSpeechSettingsChanged, then that event should be used to signal text-to-speech settings changes instead; platforms using older starboard versions should use kSbEventTypeAccessiblitySettingsChanged for text-to-speech settings changes.
An optional event that platforms may send to indicate that the application may soon be terminated (or crash) due to low memory availability. The application may respond by reducing memory consumption by running a Garbage Collection, flushing caches, or something similar. There is no requirement to respond to or handle this event, it is only advisory.
The size or position of a SbWindow has changed. The data is SbEventWindowSizeChangedData .
The platform has shown the on screen keyboard. This event is triggered by the system or by the application's OnScreenKeyboard show method. The event has int data representing a ticket. The ticket is used by the application to mark individual calls to the show method as successfully completed. Events triggered by the application have tickets passed in via SbWindowShowOnScreenKeyboard. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
The platform has hidden the on screen keyboard. This event is triggered by the system or by the application's OnScreenKeyboard hide method. The event has int data representing a ticket. The ticket is used by the application to mark individual calls to the hide method as successfully completed. Events triggered by the application have tickets passed in via SbWindowHideOnScreenKeyboard. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
The platform has focused the on screen keyboard. This event is triggered by the system or by the application's OnScreenKeyboard focus method. The event has int data representing a ticket. The ticket is used by the application to mark individual calls to the focus method as successfully completed. Events triggered by the application have tickets passed in via SbWindowFocusOnScreenKeyboard. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
The platform has blurred the on screen keyboard. This event is triggered by the system or by the application's OnScreenKeyboard blur method. The event has int data representing a ticket. The ticket is used by the application to mark individual calls to the blur method as successfully completed. Events triggered by the application have tickets passed in via SbWindowBlurOnScreenKeyboard. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
The platform has updated the on screen keyboard suggestions. This event is triggered by the system or by the application's OnScreenKeyboard update suggestions method. The event has int data representing a ticket. The ticket is used by the application to mark individual calls to the update suggestions method as successfully completed. Events triggered by the application have tickets passed in via SbWindowUpdateOnScreenKeyboardSuggestions. System-triggered events have ticket value kSbEventOnScreenKeyboardInvalidTicket.
SB_HAS(ON_SCREEN_KEYBOARD)One or more of the fields returned by SbAccessibilityGetCaptionSettings has changed.
The platform's text-to-speech settings have changed.
A function that can be called back from the main Starboard event pump.
typedef void(* SbEventCallback) (void *context)
A function that will cleanly destroy an event data instance of a specific type.
typedef void(* SbEventDataDestructor) (void *data)
An ID that can be used to refer to a scheduled event.
typedef uint32_t SbEventId
Structure representing a Starboard event and its data.
void * data
Event data for kSbEventTypeStart events.
char ** argument_values
The command-line argument values (argv).
The command-line argument count (argc).
const char * link
The startup link, if any.
Event data for kSbEventTypeWindowSizeChanged events.
Cancels the specified
event_id. Note that this function is a no-op if the
event already fired. This function can be safely called from any thread, but the
only way to guarantee that the event does not run anyway is to call it from the
main Starboard event loop thread.
void SbEventCancel(SbEventId event_id)
The entry point that Starboard applications MUST implement. Any memory pointed
event or the
data field inside
event is owned by the system, and
that memory is reclaimed after this function returns, so the implementation must
copy this data to extend its life. This behavior should also be assumed of all
fields within the
data object, unless otherwise explicitly specified.
This function is only called from the main Starboard thread. There is no specification about what other work might happen on this thread, so the application should generally do as little work as possible on this thread, and just dispatch it over to another thread.
SB_IMPORT void SbEventHandle(const SbEvent *event)
Returns whether the given event handle is valid.
static bool SbEventIsIdValid(SbEventId handle)
Schedules an event
callback into the main Starboard event loop. This function
may be called from any thread, but
callback is always called from the main
Starboard thread, queued with other pending events.
callback: The callback function to be called.
context: The context that is
passed to the
delay: The minimum number of microseconds
to wait before calling the
callback function. Set
0 to call the
callback as soon as possible.
SbEventId SbEventSchedule(SbEventCallback callback, void *context, SbTime delay)