harmony 鸿蒙native_vsync.h

2025-06-12
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native_vsync.h

Overview

The native_vsync.h file declares the functions for obtaining and using native virtual synchronization (VSync).

Since: 9

Related module: NativeVsync

Summary

Types

Name	Description
typedef enum OHNativeErrorCode OHNativeErrorCode	Defines an enum for the error codes.
typedef struct OH_NativeVSync OH_NativeVSync	Provides the declaration of an OH_NativeVSync struct.
typedef void(* OH_NativeVSync_FrameCallback) (long long timestamp, void *data)	Defines the pointer to a VSync callback function.

Enums

Name	Description
OHNativeErrorCode { NATIVE_ERROR_OK = 0, NATIVE_ERROR_MEM_OPERATION_ERROR = 30001000, NATIVE_ERROR_INVALID_ARGUMENTS = 40001000, NATIVE_ERROR_NO_PERMISSION = 40301000, NATIVE_ERROR_NO_BUFFER = 40601000, NATIVE_ERROR_NO_CONSUMER = 41202000, NATIVE_ERROR_NOT_INIT = 41203000, NATIVE_ERROR_CONSUMER_CONNECTED = 41206000, NATIVE_ERROR_BUFFER_STATE_INVALID = 41207000, NATIVE_ERROR_BUFFER_IN_CACHE = 41208000, NATIVE_ERROR_BUFFER_QUEUE_FULL = 41209000, NATIVE_ERROR_BUFFER_NOT_IN_CACHE = 41210000,NATIVE_ERROR_CONSUMER_DISCONNECTED = 41211000,NATIVE_ERROR_CONSUMER_NO_LISTENER_REGISTERED = 41212000, NATIVE_ERROR_UNSUPPORTED = 50102000, NATIVE_ERROR_UNKNOWN = 50002000, NATIVE_ERROR_HDI_ERROR = 50007000,NATIVE_ERROR_BINDER_ERROR = 50401000, NATIVE_ERROR_EGL_STATE_UNKNOWN = 60001000, NATIVE_ERROR_EGL_API_FAILED = 60002000 }	Enumerates the error codes.

Name

Description

OHNativeErrorCode {
NATIVE_ERROR_OK = 0, NATIVE_ERROR_MEM_OPERATION_ERROR = 30001000, NATIVE_ERROR_INVALID_ARGUMENTS = 40001000, NATIVE_ERROR_NO_PERMISSION = 40301000, NATIVE_ERROR_NO_BUFFER = 40601000,
NATIVE_ERROR_NO_CONSUMER = 41202000, NATIVE_ERROR_NOT_INIT = 41203000, NATIVE_ERROR_CONSUMER_CONNECTED = 41206000, NATIVE_ERROR_BUFFER_STATE_INVALID = 41207000,
NATIVE_ERROR_BUFFER_IN_CACHE = 41208000, NATIVE_ERROR_BUFFER_QUEUE_FULL = 41209000, NATIVE_ERROR_BUFFER_NOT_IN_CACHE = 41210000,NATIVE_ERROR_CONSUMER_DISCONNECTED = 41211000,NATIVE_ERROR_CONSUMER_NO_LISTENER_REGISTERED = 41212000, NATIVE_ERROR_UNSUPPORTED = 50102000,
NATIVE_ERROR_UNKNOWN = 50002000, NATIVE_ERROR_HDI_ERROR = 50007000,NATIVE_ERROR_BINDER_ERROR = 50401000, NATIVE_ERROR_EGL_STATE_UNKNOWN = 60001000, NATIVE_ERROR_EGL_API_FAILED = 60002000
}

Enumerates the error codes.

Functions

Name	Description
OH_NativeVSync_Create (const char *name, unsigned int length)	Creates an OH_NativeVSync instance. A new OH_NativeVSync instance is created each time this function is called.
OH_NativeVSync * OH_NativeVSync_Create_ForAssociatedWindow (uint64_t windowID, const char *name, unsigned int length)	Creates an OH_NativeVSync instance to bind with a window. A new OH_NativeVSync instance is created each time this API is called.
OH_NativeVSync_Destroy (OH_NativeVSync *nativeVsync)	Destroys an OH_NativeVSync instance.
int OH_NativeVSync_RequestFrame (OH_NativeVSync nativeVsync, OH_NativeVSync_FrameCallback callback, void data)	Requests the next VSync signal. When the signal arrives, a callback function is invoked. If this function is called for multiple times in the same frame, only the last callback function is invoked. If this function and the OH_NativeVSync_RequestFrameWithMultiCallback function are called in the same frame, the current function call does not take effect.
int OH_NativeVSync_RequestFrameWithMultiCallback (OH_NativeVSync nativeVsync, OH_NativeVSync_FrameCallback callback, void data)	Requests the next VSync signal. When the signal arrives, a callback function is invoked. If this function is called for multiple times in the same frame, every callback function is invoked.
OH_NativeVSync_GetPeriod (OH_NativeVSync nativeVsync, long long period)	Obtains the VSync period.
int OH_NativeVSync_DVSyncSwitch (OH_NativeVSync *nativeVsync, bool enable)	Enables DVSync to improve the smoothness of self-drawing animations. DVSync, short for Decoupled VSync, is a frame timing management policy that is decoupled from the hardware’s VSync. DVSync drives the early rendering of upcoming animation frames by sending VSync signals with future timestamps. These frames are stored in a frame buffer queue. This helps DVSync reduce potential frame drop and therefore enhances the smoothness of animations. DVSync requires free self-drawing frame buffers to store these pre-rendered animation frames. Therefore, you must ensure that at least one free frame buffer is available. Otherwise, do not enable DVSync. After DVSync is enabled, you must correctly respond to the early VSync signals and request the subsequent VSync after the animation frame associated with the previous VSync is complete. In addition, the self-drawing frames must carry timestamps that align with VSync. After the animation ends, disable DVSync. On a platform that does not support DVSync or if another application has enabled DVSync, the attempt to enable it will not take effect, and the application still receives normal VSync signals.