【HarmonyOS NEXT】自定义相机拍照和录像 （一）之拍照

【HarmonyOS NEXT】自定义相机拍照和录像 （一）之拍照

一、前言

鸿蒙工具包已经提供了完整的一键扫码和一键唤起系统相机的功能，但是定制化的需求无法满足。此时我们就需要自定义相机去实现功能。

毕竟开发应用，只是调用api拉起预制的功能包就实现功能效果，那应用开发价值也太低了。

其实鸿蒙提供多种功能的工具包，确实减轻了应用开发的压力，也提高了效率。

但是我们也需要明白，这代表技术含量也被降低了，我们还是需要研究深入高级定制化的功能效果如何实现，才能提升自己的技能水平。

二、自定义相机的实现思路

通过系统提供的CameraKit调用相关相机API进行相机设备调用，相机视频流来实现。

如果只是简单的调用相机进行拍照和录像的需求，只需要调用系统相机即可。 如图所示，开发自定义相机只需要以下步骤：

1.设置相机界面

2.选择相机摄像头实例 根据cameraKit提供的CameraManager获取相机管理实例，拿到设备的相机列表，一般分为前后两个。选择你要用的相机。

3.相机输出流 传入你选择的相机实例给cameraManager.createCameraInput创建相机输出流，开启会话后cameraInput.open，进行相机的参数配置（拍照还是摄像模式，闪光灯，焦距比）

4.配置相机会话信息 创建会话，将输入流，输出流，拍照，摄像，绑定到会话上。完事之后，开启会话，相机流就能正常输出。你去操作拍照摄像也可以正常操作。你可以理解会话为一个组合器。

5.退出界面销毁相机 相机资源不释放，会导致再次初始化黑屏，甚至影响系统相机等异常问题。

import { camera } from '@kit.CameraKit';
import { image } from '@kit.ImageKit';
import { BusinessError } from '@kit.BasicServicesKit';

export class CameraMgr {
  private TAG: string = "CameraMgr";

  private static mCameraMgr: CameraMgr | null = null;

  private mPhotoOutput: camera.PhotoOutput | undefined = undefined;
  private mPhotoSession: camera.PhotoSession | undefined = undefined;
  private mCameraInput: camera.CameraInput | undefined = undefined;
  private mPreviewOutput: camera.PreviewOutput | undefined = undefined;

  public static Ins(): CameraMgr {
    if (CameraMgr.mCameraMgr) {
      return CameraMgr.mCameraMgr
    }
    CameraMgr.mCameraMgr = new CameraMgr();
    return CameraMgr.mCameraMgr
  }

  /**
   * 初始化相机
   * @param baseContext
   * @param surfaceId
   */
  public async initCamera(baseContext: Context, surfaceId: string) {
    // 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) => {
      if (err !== undefined && err.code !== 0) {
        console.error('cameraStatus with errorCode = ' + err.code);
        return;
      }
      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 {
      // 配置后置摄像头
      cameraInput = cameraManager.createCameraInput(cameraArray[0]);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to createCameraInput errorCode = ' + err.code);
    }
    if (cameraInput === undefined) {
      return;
    }
    this.mCameraInput = cameraInput;
    // 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
    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;
    }
    this.mPreviewOutput = previewOutput;
    // 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;
    }

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

    //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;
    }
    this.mPhotoSession = photoSession;
    // 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);
    }


  }

  /**
   * 相机拍照
   */
  public capturePhoto(){
    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
    this.mPhotoOutput?.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.');
    });
  }

  /**
   * 销毁相机
   */
  public async destroyCamera(){

    // 需要在拍照结束之后调用以下关闭摄像头和释放会话流程，避免拍照未结束就将会话释放。
    // 停止当前会话
    await this.mPhotoSession?.stop();

    // 释放相机输入流
    await this.mCameraInput?.close();

    // 释放预览输出流
    await this.mPreviewOutput?.release();

    // 释放拍照输出流
    await this.mPhotoOutput?.release();

    // 释放会话
    await this.mPhotoSession?.release();

    // 会话置空
    this.mPhotoSession = undefined;
  }

  /**
   * 设置相机拍照回调
   */
  public setPhotoOutput(){
    // 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
    this.mPhotoOutput?.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;
          }

          // 如需要在图库中看到所保存的图片、视频资源，请使用用户无感的安全控件创建媒体资源。

          // buffer处理结束后需要释放该资源，如果未正确释放资源会导致后续拍照获取不到buffer
          imageObj.release();
        });
      });
  }
}