图片接收

开发步骤

添加依赖

在进行应用开发之前，开发者需要打开native工程的src/main/cpp/CMakeLists.txt，在target_link_libraries依赖中添加libace_napi.z.so、libimage_ndk.z.so、libimage_receiver_ndk.z.so、libnative_image.so以及日志依赖libhilog_ndk.z.so。

target_link_libraries(entry PUBLIC libace_napi.z.so libhilog_ndk.z.so libimage_ndk.z.so libimage_receiver_ndk.z.so libnative_image.so)

添加接口映射

打开src/main/cpp/hello.cpp文件，在Init函数中添加接口映射如下：

EXTERN_C_START
static napi_value Init(napi_env env, napi_value exports)
{
    napi_property_descriptor desc[] = {
        { "createFromReceiver", nullptr, createFromReceiver, nullptr, nullptr, nullptr, napi_default, nullptr },
    };

    napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);
    return exports;
}
EXTERN_C_END

添加权限申请

此处通过camera图片获取输入数据，需要申请权限ohos.permission.CAMERA，申请方式请参考向用户申请授权。

JS侧调用

1. 打开src\main\cpp\types\libentry\index.d.ts（其中libentry根据工程名生成），导入如下引用文件：

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   自动换行

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   复制

   import { image } from '@kit.ImageKit';
   
   export const createFromReceiver: (a: image.ImageReceiver) => image.Image;

2. 打开src\main\ets\pages\index.ets，导入"libentry.so（根据工程名生成）"，调用Native接口，传入JS的资源对象。示例如下：

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   import testNapi from 'libentry.so';
   import { image } from '@kit.ImageKit';
   import { common, abilityAccessCtrl } from '@kit.AbilityKit';
   import { camera } from '@kit.CameraKit';
   
   @Entry
   @Component
   struct Index {
     private receiver: image.ImageReceiver | undefined = undefined;
     func (){
        let context = this.getUIContext().getHostContext() as common.UIAbilityContext;
        abilityAccessCtrl.createAtManager().requestPermissionsFromUser(context,['ohos.permission.CAMERA']).then(async () => {
           let cameraManager = await camera.getCameraManager(context);
           // 获取支持的相机设备对象。
           let cameraDevices: Array<camera.CameraDevice> = cameraManager.getSupportedCameras();
           if (cameraDevices.length <= 0) {
           return;
           }
           // 获取对应相机设备的profiles。
           let profiles: camera.CameraOutputCapability = cameraManager.getSupportedOutputCapability(cameraDevices[0], camera.SceneMode.NORMAL_PHOTO);
           let previewProfiles: Array<camera.Profile> = profiles.previewProfiles;
           if (previewProfiles.length <= 0) {
           return;
           }
           let profileObj = previewProfiles[0];
           this.receiver = image.createImageReceiver({width:profileObj.size.width, height:profileObj.size.height}, image.ImageFormat.JPEG, 8);
           let receiverSurfaceId: string = await this.receiver.getReceivingSurfaceId();
           // 创建预览流输出对象。
           let previewOutput: camera.PreviewOutput = cameraManager.createPreviewOutput(profileObj,receiverSurfaceId);
           let cameraInput : camera.CameraInput = cameraManager.createCameraInput(cameraDevices[0]);
           // 打开相机。
           await cameraInput.open();
           // 会话流程。
           let session : camera.PhotoSession = cameraManager.createSession(camera.SceneMode.NORMAL_PHOTO) as camera.PhotoSession;
           // 配置会话。
           session.beginConfig();
           // 把cameraInput加入到会话。
           session.addInput(cameraInput);
           // 把预览流加入到会话。
           session.addOutput(previewOutput);
           // 提交配置信息。
           await session.commitConfig();
           // 会话开始。
           await session.start();
   
           this.receiver.on('imageArrival', () => {
              let img : image.Image = testNapi.createFromReceiver(this.receiver);
              img.release();
           })
   
        });
     }
   
     build() {
        Row() {
           Column() {
           Button("start")
              .width(100)
              .height(100)
              .onClick(() => {
                 console.info("button click in");
                 if (this.receiver == undefined) {
                    this.func();
                 }
              })
           }
           .width('100%')
        }
        .height('100%')
     }
   }

Native接口调用

具体接口说明请参考Image。

在hello.cpp文件中获取JS的资源对象，并转为Native的资源对象，即可调用Native接口，调用方式示例代码如下：

添加引用文件

#include <multimedia/image_framework/image_mdk.h>
#include <multimedia/image_framework/image_receiver_mdk.h>
#include <hilog/log.h>

static napi_value createFromReceiver(napi_env env, napi_callback_info info)
{
   size_t argc = 1;
   napi_value args[2] = {nullptr};
   napi_get_cb_info(env, info, &argc, args , nullptr, nullptr);
   napi_valuetype valuetype0;
   napi_typeof(env, args[0], &valuetype0);
   napi_ref reference;
   napi_create_reference(env, args[0], 1 ,&reference);
   napi_value imgReceiver_js;
   napi_get_reference_value(env, reference, &imgReceiver_js);
   
   ImageReceiverNative * imgReceiver_c = OH_Image_Receiver_InitImageReceiverNative(env, imgReceiver_js);

   int32_t capacity;
   OH_Image_Receiver_GetCapacity(imgReceiver_c, &capacity);
   OH_LOG_Print(LOG_APP, LOG_INFO, 0xFF00, "[receiver]", "capacity: %{public}d", capacity);
   int32_t format;
   OH_Image_Receiver_GetFormat(imgReceiver_c, &format);
   OH_LOG_Print(LOG_APP, LOG_INFO, 0xFF00, "[receiver]", "format: %{public}d", format);
   char surfaceId[128] = {0};
   OH_Image_Receiver_GetReceivingSurfaceId(imgReceiver_c, surfaceId, sizeof(surfaceId));
   OH_LOG_Print(LOG_APP, LOG_INFO, 0xFF00, "[receiver]", "surfaceId: %{public}s", surfaceId);
   OhosImageSize size;
   OH_Image_Receiver_GetSize(imgReceiver_c, &size);
   OH_LOG_Print(LOG_APP, LOG_INFO, 0xFF00, "[receiver]", "OH_Image_Receiver_GetSize  width: %{public}d, height:%{public}d", size.width, size.height);

   napi_value nextImage;
   // 或调用 OH_Image_Receiver_ReadNextImage(imgReceiver_c, &nextImage);
   OH_Image_Receiver_ReadLatestImage(imgReceiver_c, &nextImage);
   
   ImageNative * nextImage_native = OH_Image_InitImageNative(env, nextImage);

   OhosImageSize imageSize;
   OH_Image_Size(nextImage_native, &imageSize);
   OH_LOG_Print(LOG_APP, LOG_INFO, 0xFF00, "[receiver]", "OH_Image_Size  width: %{public}d, height:%{public}d", imageSize.width, imageSize.height);

   OhosImageComponent imgComponent;
   OH_Image_GetComponent(nextImage_native, OHOS_IMAGE_COMPONENT_FORMAT_JPEG, &imgComponent);
   
   uint8_t *img_buffer = imgComponent.byteBuffer;
   
   OH_Image_Release(nextImage_native);
   OH_Image_Receiver_Release(imgReceiver_c);
   return nextImage;
}