include/android/choreographer.h

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @addtogroup Choreographer
 * @{
 */

/**
 * @file choreographer.h
 */

#ifndef ANDROID_CHOREOGRAPHER_H
#define ANDROID_CHOREOGRAPHER_H

#include <stdint.h>
#include <sys/cdefs.h>

__BEGIN_DECLS

struct AChoreographer;
/**
 * Opaque type that provides access to an AChoreographer object.
 *
 * A pointer can be obtained using {@link AChoreographer_getInstance()}.
 */
typedef struct AChoreographer AChoreographer;

/**
 * Prototype of the function that is called when a new frame is being rendered.
 * It's passed the time that the frame is being rendered as nanoseconds in the
 * CLOCK_MONOTONIC time base, as well as the data pointer provided by the
 * application that registered a callback. All callbacks that run as part of
 * rendering a frame will observe the same frame time, so it should be used
 * whenever events need to be synchronized (e.g. animations).
 */
typedef void (*AChoreographer_frameCallback)(long frameTimeNanos, void* data);

/**
 * Prototype of the function that is called when a new frame is being rendered.
 * It's passed the time that the frame is being rendered as nanoseconds in the
 * CLOCK_MONOTONIC time base, as well as the data pointer provided by the
 * application that registered a callback. All callbacks that run as part of
 * rendering a frame will observe the same frame time, so it should be used
 * whenever events need to be synchronized (e.g. animations).
 */
typedef void (*AChoreographer_frameCallback64)(int64_t frameTimeNanos, void* data);

/**
 * Prototype of the function that is called when the display refresh rate
 * changes. It's passed the new vsync period in nanoseconds, as well as the data
 * pointer provided by the application that registered a callback.
 */
typedef void (*AChoreographer_refreshRateCallback)(int64_t vsyncPeriodNanos, void* data);

/**
 * Get the AChoreographer instance for the current thread. This must be called
 * on an ALooper thread.
 *
 * Available since API level 24.
 */
AChoreographer* AChoreographer_getInstance() __INTRODUCED_IN(24);

/**
 * Deprecated: Use AChoreographer_postFrameCallback64 instead.
 */
void AChoreographer_postFrameCallback(AChoreographer* choreographer,
                                      AChoreographer_frameCallback callback, void* data)
        __INTRODUCED_IN(24) __DEPRECATED_IN(29);

/**
 * Deprecated: Use AChoreographer_postFrameCallbackDelayed64 instead.
 */
void AChoreographer_postFrameCallbackDelayed(AChoreographer* choreographer,
                                             AChoreographer_frameCallback callback, void* data,
                                             long delayMillis) __INTRODUCED_IN(24)
        __DEPRECATED_IN(29);

/**
 * Power a callback to be run on the next frame.  The data pointer provided will
 * be passed to the callback function when it's called.
 *
 * Available since API level 29.
 */
void AChoreographer_postFrameCallback64(AChoreographer* choreographer,
                                        AChoreographer_frameCallback64 callback, void* data)
        __INTRODUCED_IN(29);

/**
 * Post a callback to be run on the frame following the specified delay.  The
 * data pointer provided will be passed to the callback function when it's
 * called.
 *
 * Available since API level 29.
 */
void AChoreographer_postFrameCallbackDelayed64(AChoreographer* choreographer,
                                               AChoreographer_frameCallback64 callback, void* data,
                                               uint32_t delayMillis) __INTRODUCED_IN(29);

/**
 * Registers a callback to be run when the display refresh rate changes. The
 * data pointer provided will be passed to the callback function when it's
 * called. The same callback may be registered multiple times, provided that a
 * different data pointer is provided each time.
 *
 * If an application registers a callback for this choreographer instance when
 * no new callbacks were previously registered, that callback is guaranteed to
 * be dispatched. However, if the callback and associated data pointer are
 * unregistered prior to running the callback, then the callback may be silently
 * dropped.
 *
 * This api is thread-safe. Any thread is allowed to register a new refresh
 * rate callback for the choreographer instance.
 *
 * Note that in API level 30, this api is not guaranteed to be atomic with
 * DisplayManager. That is, calling Display#getRefreshRate very soon after
 * a refresh rate callback is invoked may return a stale refresh rate. If any
 * Display properties would be required by this callback, then it is recommended
 * to listen directly to DisplayManager.DisplayListener#onDisplayChanged events
 * instead.
 *
 * As of API level 31, this api is guaranteed to have a consistent view with DisplayManager;
 * Display#getRefreshRate is guaranteed to not return a stale refresh rate when invoked from this
 * callback.
 *
 * Available since API level 30.
 */
void AChoreographer_registerRefreshRateCallback(AChoreographer* choreographer,
                                                AChoreographer_refreshRateCallback, void* data)
        __INTRODUCED_IN(30);

/**
 * Unregisters a callback to be run when the display refresh rate changes, along
 * with the data pointer previously provided when registering the callback. The
 * callback is only unregistered when the data pointer matches one that was
 * previously registered.
 *
 * This api is thread-safe. Any thread is allowed to unregister an existing
 * refresh rate callback for the choreographer instance. When a refresh rate
 * callback and associated data pointer are unregistered, then there is a
 * guarantee that when the unregistration completes that that callback will not
 * be run with the data pointer passed.
 *
 * Available since API level 30.
 */
void AChoreographer_unregisterRefreshRateCallback(AChoreographer* choreographer,
                                                  AChoreographer_refreshRateCallback, void* data)
        __INTRODUCED_IN(30);

__END_DECLS

#endif // ANDROID_CHOREOGRAPHER_H

/** @} */