HarmonyOS 如何在拍照的时候加上图片遮罩

目前应用有个场景，需要对用户身份做认证，需要用户上传身份证正面和国徽面，希望在拍照片的时候在拍摄页面上加一个身份证半透明提示(或者国徽半透明照片)，以提醒用户当前需要拍摄身份证正面(或者国徽面)请问这该怎么操作?

解决方案

参考demo：

import abilityAccessCtrl, { Context, PermissionRequestResult, Permissions } from '@ohos.abilityAccessCtrl';
import { BusinessError } from '@ohos.base';
import common from '@ohos.app.ability.common';
import camera from '@ohos.multimedia.camera';
import { image } from '@kit.ImageKit';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import fs from '@ohos.file.fs';

let context = getContext(this);

@Entry
@Component
struct PagePreview {
  mXComponentController: XComponentController = new XComponentController;
  surfaceId: string = '';
  isUserAgent: boolean = false
  @State pixelMap: PixelMap | undefined = undefined
  @State photoOutput: camera.PhotoOutput | undefined = undefined;

  getPermission(permissions: Permissions[]): Promise<boolean> {
    let atManager: abilityAccessCtrl.AtManager = abilityAccessCtrl.createAtManager();
    let context: Context = getContext(this) as common.UIAbilityContext;
    return new Promise((resolve, reject) => {
      atManager.requestPermissionsFromUser(context, permissions,
        (err: BusinessError, data: PermissionRequestResult) => {
          if (err) {
            console.log(`requestPermissionsFromUser fail, err->${JSON.stringify(err)}`);
            return resolve(false)
          } else {
            console.info('data:' + JSON.stringify(data));
            console.info('data permissions:' + data.permissions);
            console.info('data authResults:' + data.authResults);
            return resolve(true)
          }
        });
    })
  }

  async savePicture(buffer: ArrayBuffer, img: image.Image): Promise<void> {
    let imageResource = image.createImageSource(buffer);
    imageResource.createPixelMap({}).then((res) => {
      this.pixelMap = res;
    });
    return
    let accessHelper: photoAccessHelper.PhotoAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
    let options: photoAccessHelper.CreateOptions = {
      title: Date.now().toString()
    };
    let photoUri: string = await accessHelper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg', options);
    //createAsset的调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限
    let file: fs.File = fs.openSync(photoUri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
    await fs.write(file.fd, buffer);
    fs.closeSync(file);
    img.release();
  }

  setPhotoOutputCb(photoOutput: camera.PhotoOutput): void {
    //设置回调之后，调用photoOutput的capture方法，就会将拍照的buffer回传到回调中
    photoOutput.on('photoAvailable', (errCode: BusinessError, photo: camera.Photo): void => {
      console.info('getPhoto start');
      console.info(`err: ${JSON.stringify(errCode)}`);
      if (errCode || photo === undefined) {
        console.error('getPhoto failed');
        return;
      }
      let imageObj = photo.main;
      imageObj.getComponent(image.ComponentType.JPEG, (errCode: BusinessError, component: image.Component): void => {
        console.info('getComponent start');
        if (errCode || component === undefined) {
          console.error('getComponent failed');
          return;
        }
        let buffer: ArrayBuffer;
        if (component.byteBuffer) {
          buffer = component.byteBuffer;
        } else {
          console.error('byteBuffer is null');
          return;
        }
        this.savePicture(buffer, imageObj);
      });
    });
  }

  async cameraShootingCase(baseContext: common.BaseContext, surfaceId: string): Promise<void> {
    // 创建CameraManager对象
    let cameraManager: camera.CameraManager = camera.getCameraManager(baseContext);
    if (!cameraManager) {
      console.error("camera.getCameraManager error");
      return;
    }
    // 监听相机状态变化
    cameraManager.on('cameraStatus', (err: BusinessError, cameraStatusInfo: camera.CameraStatusInfo) => {
      console.info(`camera : ${cameraStatusInfo.camera.cameraId}`);
      console.info(`status: ${cameraStatusInfo.status}`);
    });

    // 获取相机列表
    let cameraArray: Array<camera.CameraDevice> = cameraManager.getSupportedCameras();
    if (cameraArray.length <= 0) {
      console.error("cameraManager.getSupportedCameras error");
      return;
    }

    for (let index = 0; index < cameraArray.length; index++) {
      console.info('cameraId : ' + cameraArray[index].cameraId); // 获取相机ID
      console.info('cameraPosition : ' + cameraArray[index].cameraPosition); // 获取相机位置
      console.info('cameraType : ' + cameraArray[index].cameraType); // 获取相机类型
      console.info('connectionType : ' + cameraArray[index].connectionType); // 获取相机连接类型
    }

    // 创建相机输入流
    let cameraInput: camera.CameraInput | undefined = undefined;
    try {
      cameraInput = cameraManager.createCameraInput(cameraArray[0]);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to createCameraInput errorCode = ' + err.code);
    }
    if (cameraInput === undefined) {
      return;
    }

    // 监听cameraInput错误信息
    let cameraDevice: camera.CameraDevice = cameraArray[0];
    cameraInput.on('error', cameraDevice, (error: BusinessError) => {
      console.error(`Camera input error code: ${error.code}`);
    })

    // 打开相机
    await cameraInput.open();

    // 获取支持的模式类型
    let sceneModes: Array<camera.SceneMode> = cameraManager.getSupportedSceneModes(cameraArray[0]);
    let isSupportPhotoMode: boolean = sceneModes.indexOf(camera.SceneMode.NORMAL_PHOTO) >= 0;
    if (!isSupportPhotoMode) {
      console.error('photo mode not support');
      return;
    }
    // 获取相机设备支持的输出流能力
    let cameraOutputCap: camera.CameraOutputCapability =
      cameraManager.getSupportedOutputCapability(cameraArray[0], camera.SceneMode.NORMAL_PHOTO);
    if (!cameraOutputCap) {
      console.error("cameraManager.getSupportedOutputCapability error");
      return;
    }
    console.info("outputCapability: " + JSON.stringify(cameraOutputCap));

    let previewProfilesArray: Array<camera.Profile> = cameraOutputCap.previewProfiles;
    if (!previewProfilesArray) {
      console.error("createOutput previewProfilesArray == null || undefined");
    }

    let photoProfilesArray: Array<camera.Profile> = cameraOutputCap.photoProfiles;
    if (!photoProfilesArray) {
      console.error("createOutput photoProfilesArray == null || undefined");
    }

    // 创建预览输出流,其中参数 surfaceId 参考上文 XComponent 组件，预览流为XComponent组件提供的surface
    let previewOutput: camera.PreviewOutput | undefined = undefined;
    try {
      previewOutput = cameraManager.createPreviewOutput(previewProfilesArray[0], surfaceId);
    } catch (error) {
      let err = error as BusinessError;
      console.error(`Failed to create the PreviewOutput instance. error code: ${err.code}`);
    }
    if (previewOutput === undefined) {
      return;
    }
    // 监听预览输出错误信息
    previewOutput.on('error', (error: BusinessError) => {
      console.error(`Preview output error code: ${error.code}`);
    });

    // 创建拍照输出流
    let photoOutput: camera.PhotoOutput | undefined = undefined;
    try {
      photoOutput = cameraManager.createPhotoOutput(photoProfilesArray[0]);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to createPhotoOutput errorCode = ' + err.code);
    }
    if (photoOutput === undefined) {
      return;
    }

    //调用上面的回调函数来保存图片
    this.setPhotoOutputCb(photoOutput);

    //创建会话
    let photoSession: camera.PhotoSession | undefined = undefined;
    try {
      photoSession = cameraManager.createSession(camera.SceneMode.NORMAL_PHOTO) as camera.PhotoSession;
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to create the session instance. errorCode = ' + err.code);
    }
    if (photoSession === undefined) {
      return;
    }
    // 监听session错误信息
    photoSession.on('error', (error: BusinessError) => {
      console.error(`Capture session error code: ${error.code}`);
    });

    // 开始配置会话
    try {
      photoSession.beginConfig();
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to beginConfig. errorCode = ' + err.code);
    }

    // 向会话中添加相机输入流
    try {
      photoSession.addInput(cameraInput);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to addInput. errorCode = ' + err.code);
    }

    // 向会话中添加预览输出流
    try {
      photoSession.addOutput(previewOutput);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to addOutput(previewOutput). errorCode = ' + err.code);
    }

    // 向会话中添加拍照输出流
    try {
      photoSession.addOutput(photoOutput);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to addOutput(photoOutput). errorCode = ' + err.code);
    }

    // 提交会话配置
    await photoSession.commitConfig();

    // 启动会话
    await photoSession.start().then(() => {
      console.info('Promise returned to indicate the session start success.');
    });
    // 判断设备是否支持闪光灯
    let flashStatus: boolean = false;
    try {
      flashStatus = photoSession.hasFlash();
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to hasFlash. errorCode = ' + err.code);
    }
    console.info('Returned with the flash light support status:' + flashStatus);

    if (flashStatus) {
      // 判断是否支持自动闪光灯模式
      let flashModeStatus: boolean = false;
      try {
        let status: boolean = photoSession.isFlashModeSupported(camera.FlashMode.FLASH_MODE_AUTO);
        flashModeStatus = status;
      } catch (error) {
        let err = error as BusinessError;
        console.error('Failed to check whether the flash mode is supported. errorCode = ' + err.code);
      }
      if (flashModeStatus) {
        // 设置自动闪光灯模式
        try {
          photoSession.setFlashMode(camera.FlashMode.FLASH_MODE_AUTO);
        } catch (error) {
          let err = error as BusinessError;
          console.error('Failed to set the flash mode. errorCode = ' + err.code);
        }
      }
    }

    // 判断是否支持连续自动变焦模式
    let focusModeStatus: boolean = false;
    try {
      let status: boolean = photoSession.isFocusModeSupported(camera.FocusMode.FOCUS_MODE_CONTINUOUS_AUTO);
      focusModeStatus = status;
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to check whether the focus mode is supported. errorCode = ' + err.code);
    }

    if (focusModeStatus) {
      // 设置连续自动变焦模式
      try {
        photoSession.setFocusMode(camera.FocusMode.FOCUS_MODE_CONTINUOUS_AUTO);
      } catch (error) {
        let err = error as BusinessError;
        console.error('Failed to set the focus mode. errorCode = ' + err.code);
      }
    }

    // 获取相机支持的可变焦距比范围
    let zoomRatioRange: Array<number> = [];
    try {
      zoomRatioRange = photoSession.getZoomRatioRange();
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to get the zoom ratio range. errorCode = ' + err.code);
    }
    if (zoomRatioRange.length <= 0) {
      return;
    }
    // 设置可变焦距比
    try {
      photoSession.setZoomRatio(zoomRatioRange[0]);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to set the zoom ratio value. errorCode = ' + err.code);
    }
    let photoCaptureSetting: camera.PhotoCaptureSetting = {
      quality: camera.QualityLevel.QUALITY_LEVEL_HIGH, // 设置图片质量高
      rotation: camera.ImageRotation.ROTATION_0 // 设置图片旋转角度0
    }
    // 使用当前拍照设置进行拍照
    photoOutput.capture(photoCaptureSetting, (err: BusinessError) => {
      if (err) {
        console.error(`Failed to capture the photo ${err.message}`);
        return;
      }
      console.info('Callback invoked to indicate the photo capture request success.');
    });
  }

  aboutToAppear(): void {
    //user_grant用户授权
    this.getPermission(['ohos.permission.CAMERA']).then(async (res) => {
      console.log(String(res))
      if (!res) {
        return
      }
    })
  }

  aboutToDisappear(): void {
  }

  build() {
    Column() {

      // 创建XComponent
      Stack(){
        XComponent({
          id: '',
          type: 'surface',
          libraryname: '',
          controller: this.mXComponentController
        })
          .onLoad(() => {
            // 设置Surface宽高（1920*1080），预览尺寸设置参考前面 previewProfilesArray 获取的当前设备所支持的预览分辨率大小去设置
            // 预览流与录像输出流的分辨率的宽高比要保持一致
            this.mXComponentController.setXComponentSurfaceSize({ surfaceWidth: 640, surfaceHeight: 980 });
            // 获取Surface ID
            this.surfaceId = this.mXComponentController.getXComponentSurfaceId();
          })
          .width('100%')
          .height('100%')
          .zIndex(1)

        Row(){}.width('100%')
        .height('100%').zIndex(2).backgroundColor(Color.Black).opacity(0.6)
        Button("拍照").onClick(async () => {
          await this.cameraShootingCase(getContext(), this.surfaceId)
        }).zIndex(3)
      }
    }
    .height('100%')
    .width('100%')
  }
}