NativeDisplaySoloist开发指导 (C/C++)

如果开发者想在独立线程中进行帧率控制的Native侧业务，可以通过DisplaySoloist来实现，如游戏、自绘制UI框架对接等场景。开发者可以选择多个DisplaySoloist实例共享一个线程，也可以选择每个DisplaySoloist实例独占一个线程。

接口说明

函数名称	说明
OH_DisplaySoloist* OH_DisplaySoloist_Create (bool useExclusiveThread)	创建一个OH_DisplaySoloist实例。
OH_DisplaySoloist_Destroy (OH_DisplaySoloist * displaySoloist)	销毁一个OH_DisplaySoloist实例。
OH_DisplaySoloist_Start (OH_DisplaySoloist * displaySoloist, OH_DisplaySoloist_FrameCallback callback, void * data )	设置每帧回调函数，每次VSync信号到来时启动每帧回调。
OH_DisplaySoloist_Stop (OH_DisplaySoloist * displaySoloist)	停止请求下一次VSync信号，并停止调用回调函数callback。
OH_DisplaySoloist_SetExpectedFrameRateRange (OH_DisplaySoloist* displaySoloist, DisplaySoloist_ExpectedRateRange* range)	设置期望帧率范围。

开发示例

本范例是通过Drawing在Native侧实现图形的绘制，通过异步线程设置期望的帧率，再根据帧率进行图形的绘制并将其呈现在NativeWindow上，图形绘制部分可参考使用Drawing实现图形绘制与显示。

添加开发依赖

添加动态链接库

CMakeLists.txt中添加以下lib。

libace_napi.z.so
libace_ndk.z.so
libnative_window.so
libnative_drawing.so
libnative_display_soloist.so

头文件

#include <ace/xcomponent/native_interface_xcomponent.h>
#include "napi/native_api.h"
#include <native_display_soloist/native_display_soloist.h>
#include <native_drawing/drawing_bitmap.h>
#include <native_drawing/drawing_color.h>
#include <native_drawing/drawing_canvas.h>
#include <native_drawing/drawing_pen.h>
#include <native_drawing/drawing_brush.h>
#include <native_drawing/drawing_path.h>
#include <native_window/external_window.h>
#include <cmath>
#include <algorithm>
#include <stdint.h>
#include <sys/mman.h>

开发步骤

定义ArkTS接口文件XComponentContext.ts，用来对接Native层。

export default interface XComponentContext {
  register(): void;
  unregister(): void;
  destroy(): void;
};

定义演示页面，包含两个XComponent组件。

import XComponentContext from "../interface/XComponentContext";

@Entry
@Component
struct Index {
  private xComponentContext1: XComponentContext | undefined = undefined;
  private xComponentContext2: XComponentContext | undefined = undefined;

  build() {
    Column() {
      Row() {
        XComponent({ id: 'xcomponentId30', type: 'surface', libraryname: 'entry' })
          .onLoad((xComponentContext) => {
            this.xComponentContext1 = xComponentContext as XComponentContext;
          }).width('640px')
      }.height('40%')

      Row() {
        XComponent({ id: 'xcomponentId120', type: 'surface', libraryname: 'entry' })
          .onLoad((xComponentContext) => {
            this.xComponentContext2 = xComponentContext as XComponentContext;
          }).width('640px') // 64的倍数
      }.height('40%')
    }
  }
}

在 Native C++层获取NativeXComponent。建议使用单例模式保存XComponent。此步骤需要在napi_init的过程中处理。

创建一个PluginManger单例类，用于管理NativeXComponent。

class PluginManager {
public:
    ~PluginManager();

    static PluginManager *GetInstance();

    void SetNativeXComponent(std::string &id, OH_NativeXComponent *nativeXComponent);
    SampleBitMap *GetRender(std::string &id);
    void Export(napi_env env, napi_value exports);
private:

    std::unordered_map<std::string, OH_NativeXComponent *> nativeXComponentMap_;
    std::unordered_map<std::string, SampleXComponent *> pluginRenderMap_;
};

SampleXComponent类会在后面的绘制图形中创建。

void PluginManager::Export(napi_env env, napi_value exports) {
    nativeXComponentMap_.clear();
    pluginRenderMap_.clear();
    if ((env == nullptr) || (exports == nullptr)) {
        DRAWING_LOGE("Export: env or exports is null");
        return;
    }

    napi_value exportInstance = nullptr;
    if (napi_get_named_property(env, exports, OH_NATIVE_XCOMPONENT_OBJ, &exportInstance) != napi_ok) {
        DRAWING_LOGE("Export: napi_get_named_property fail");
        return;
    }

    OH_NativeXComponent *nativeXComponent = nullptr;
    if (napi_unwrap(env, exportInstance, reinterpret_cast<void **>(&nativeXComponent)) != napi_ok) {
        DRAWING_LOGE("Export: napi_unwrap fail");
        return;
    }

    char idStr[OH_XCOMPONENT_ID_LEN_MAX + 1] = {'\0'};
    uint64_t idSize = OH_XCOMPONENT_ID_LEN_MAX + 1;
    if (OH_NativeXComponent_GetXComponentId(nativeXComponent, idStr, &idSize) != OH_NATIVEXCOMPONENT_RESULT_SUCCESS) {
        DRAWING_LOGE("Export: OH_NativeXComponent_GetXComponentId fail");
        return;
    }

    std::string id(idStr);
    auto context = PluginManager::GetInstance();
    if ((context != nullptr) && (nativeXComponent != nullptr)) {
        context->SetNativeXComponent(id, nativeXComponent);
        auto render = context->GetRender(id);
        if (render != nullptr) {
            render->RegisterCallback(nativeXComponent);
            render->Export(env, exports);
        } else {
            DRAWING_LOGE("render is nullptr");
        }
    }
}

Native层配置帧率和注册回调函数。

定义每帧回调函数内容。

static void TestCallback(long long timestamp, long long targetTimestamp, void *data) 
{
   // ...
   // 获取对应的XComponent
    OH_NativeXComponent *component = nullptr;
    component = static_cast<OH_NativeXComponent *>(data);
    if (component == nullptr) {
       SAMPLE_LOGE("TestCallback: component is null");
       return;
    }
    char idStr[OH_XCOMPONENT_ID_LEN_MAX + 1] = {'\0'};
    uint64_t idSize = OH_XCOMPONENT_ID_LEN_MAX + 1;
    if (OH_NativeXComponent_GetXComponentId(component, idStr, &idSize) != OH_NATIVEXCOMPONENT_RESULT_SUCCESS) {
       SAMPLE_LOGE("TestCallback: Unable to get XComponent id");
       return;
    }
 
    std::string id(idStr);
    auto render = SampleXComponent::GetInstance(id);
    OHNativeWindow *nativeWindow = render->GetNativeWindow();
    uint64_t width;
    uint64_t height;
    // 获取XComponent的surface大小
    int32_t xSize = OH_NativeXComponent_GetXComponentSize(component, nativeWindow, &width, &height);
    if ((xSize == OH_NATIVEXCOMPONENT_RESULT_SUCCESS) && (render != nullptr)) {
        render->Prepare();
        render->Create();
        if (id == "xcomponentId30") {
            // 30Hz绘制时,每帧移动的距离为16像素
            render->ConstructPath(16, 16, render->defaultOffsetY);
        }
        if (id == "xcomponentId120") {
            // 120Hz绘制时，每帧移动的距离为4像素
            render->ConstructPath(4, 4, render->defaultOffsetY);
        }
  	 // ...
    }
}

使用DisplaySoloist接口配置帧率和注册每帧回调函数。

说明：

实例在调用NapiRegister后，在不需要进行帧率控制时，应进行NapiUnregister操作，避免内存泄漏问题。

在页面跳转时，应进行NapiUnregister和NapiDestroy操作，避免内存泄漏问题。

static std::unordered_map<std::string, OH_DisplaySoloist *> g_displaySync;

napi_value SampleXComponent::NapiRegister(napi_env env, napi_callback_info info)
{
    // ...
    // 获取对应的XComponent
    napi_value thisArg;
    if (napi_get_cb_info(env, info, nullptr, nullptr, &thisArg, nullptr) != napi_ok) {
       SAMPLE_LOGE("NapiRegister: napi_get_cb_info fail");
       return nullptr;
    }

    napi_value exportInstance;
    if (napi_get_named_property(env, thisArg, OH_NATIVE_XCOMPONENT_OBJ, &exportInstance) != napi_ok) {
       SAMPLE_LOGE("NapiRegister: napi_get_named_property fail");
       return nullptr;
    }

    OH_NativeXComponent *nativeXComponent = nullptr;
    if (napi_unwrap(env, exportInstance, reinterpret_cast<void **>(&nativeXComponent)) != napi_ok) {
       SAMPLE_LOGE("NapiRegister: napi_unwrap fail");
       return nullptr;
    }

    char idStr[OH_XCOMPONENT_ID_LEN_MAX + 1] = {'\0'};
    uint64_t idSize = OH_XCOMPONENT_ID_LEN_MAX + 1;
    if (OH_NativeXComponent_GetXComponentId(nativeXComponent, idStr, &idSize) != OH_NATIVEXCOMPONENT_RESULT_SUCCESS) {
       SAMPLE_LOGE("NapiRegister: Unable to get XComponent id");
       return nullptr;
    }
    SAMPLE_LOGI("RegisterID = %{public}s", idStr);
    std::string id(idStr);
    SampleXComponent *render = SampleXComponent().GetInstance(id);
    if (render != nullptr) {
       OH_DisplaySoloist *nativeDisplaySoloist = nullptr;
       if (g_displaySync.find(id) == g_displaySync.end()) {
          // 创建OH_DisplaySoloist实例
          // true表示OH_DisplaySoloist实例独占一个线程，false则表示共享一个线程
          g_displaySync[id] = OH_DisplaySoloist_Create(true);
       }
       nativeDisplaySoloist = g_displaySync[id];
       // 设置期望帧率范围
       // 此结构体成员变量分别为帧率范围的最小值、最大值以及期望帧率
       DisplaySoloist_ExpectedRateRange range;
       if (id == "xcomponentId30") {
          // 第一个XComponent期望帧率为30Hz
          range = {30, 120, 30};
       }
       if (id == "xcomponentId120") {
          // 第二个XComponent期望帧率为120Hz
          range = {30, 120, 120};
       }
       OH_DisplaySoloist_SetExpectedFrameRateRange(nativeDisplaySoloist, &range);
       // 注册回调与使能每帧回调
       OH_DisplaySoloist_Start(nativeDisplaySoloist, TestCallback, nativeXComponent);
    }
    // ...
}

napi_value SampleXComponent::NapiUnregister(napi_env env, napi_callback_info info)
{
    // ...
    // 取消注册每帧回调
    OH_DisplaySoloist_Stop(g_displaySync[id]);; 
    // ...
}

napi_value SampleXComponent::NapiDestroy(napi_env env, napi_callback_info info)
{
    // ...
    // 销毁OH_DisplaySoloist实例
    OH_DisplaySoloist_Destroy(g_displaySync[id]);
    g_displaySync.erase(id);       
    // ...
}

// 实现XComponentContext.ts中ArkTS接口与C++接口的绑定和映射。
void SampleXComponent::Export(napi_env env, napi_value exports) {
 if ((env == nullptr) || (exports == nullptr)) {
     SAMPLE_LOGE("Export: env or exports is null");
     return;
 }
 napi_property_descriptor desc[] = {
     {"register", nullptr, SampleXComponent::NapiRegister, nullptr, nullptr, nullptr, napi_default, nullptr},
     {"unregister", nullptr, SampleXComponent::NapiUnregister, nullptr, nullptr, nullptr, napi_default, nullptr},
     {"destroy", nullptr, SampleXComponent::NapiDestroy, nullptr, nullptr, nullptr, napi_default, nullptr}};

 napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);
 if (napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc) != napi_ok) {
     SAMPLE_LOGE("Export: napi_define_properties failed");
 }
}

TS层注册和取消注册每帧回调，销毁OH_DisplaySoloist实例。

// 离开页面时，取消回调注册与销毁OH_DisplaySoloist实例
aboutToDisappear(): void {
  if (this.xComponentContext1) {
    this.xComponentContext1.unregister();
    this.xComponentContext1.destroy();
  }
  if (this.xComponentContext2) {
    this.xComponentContext2.unregister();
    this.xComponentContext2.destroy();
  }
}

Row() {
    Button('Start')
      .id('Start')
      .fontSize(14)
      .fontWeight(500)
      .margin({ bottom: 20, right: 6, left: 6 })
      .onClick(() => {
        if (this.xComponentContext1) {
          this.xComponentContext1.register();
        }
        if (this.xComponentContext2) {
          this.xComponentContext2.register();
        }
      })
      .width('30%')
      .height(40)
      .shadow(ShadowStyle.OUTER_DEFAULT_LG)
    
    Button('Stop')
      .id('Stop')
      .fontSize(14)
      .fontWeight(500)
      .margin({ bottom: 20, left: 6 })
      .onClick(() => {
        if (this.xComponentContext1) {
          this.xComponentContext1.unregister();
        }
        if (this.xComponentContext2) {
          this.xComponentContext2.unregister();
        }
      })
      .width('30%')
      .height(40)
      .shadow(ShadowStyle.OUTER_DEFAULT_LG)
}

NativeDisplaySoloist开发指导 (C/C++)

接口说明

开发示例

添加开发依赖

开发步骤

相关实例