media/camera/camera-shooting-case.md

# 拍照实践(ArkTS)

在开发相机应用时，需要先参考开发准备[申请相关权限](camera-preparation.md)。

当前示例提供完整的拍照流程介绍，方便开发者了解完整的接口调用顺序。

在参考以下示例前，建议开发者查看[相机开发指导(ArkTS)](camera-preparation.md)的具体章节，了解[设备输入](camera-device-input.md)、[会话管理](camera-session-management.md)、[拍照](camera-shooting.md)等单个流程。

## 开发流程

在获取到相机支持的输出流能力后，开始创建拍照流，开发流程如下。

![Photographing Development Process](figures/photographing-development-process.png)

## 完整示例

Context获取方式请参考：[获取UIAbility的上下文信息](../../application-models/uiability-usage.md#获取uiability的上下文信息)。

如需要在图库中看到所保存的图片、视频资源，需要将其保存到媒体库，保存方式请参考：[保存媒体库资源](../medialibrary/photoAccessHelper-savebutton.md)。

需要在[photoOutput.on('photoAvailable')](../../reference/apis-camera-kit/js-apis-camera.md#onphotoavailable11)接口获取到buffer时，将buffer在安全控件中保存到媒体库。
```ts
import { camera } from '@kit.CameraKit';
import { image } from '@kit.ImageKit';
import { BusinessError } from '@kit.BasicServicesKit';

function 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: ${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();
    });
  });
}

async function cameraShootingCase(context: Context, surfaceId: string): Promise<void> {
  // 创建CameraManager对象。
  let cameraManager: camera.CameraManager = camera.getCameraManager(context);
  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 {
    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。
  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.');
  });

  // 需要在拍照结束之后调用以下关闭相机和释放会话流程，避免拍照未结束就将会话释放。
  // 停止当前会话。
  await photoSession.stop();

  // 释放相机输入流。
  await cameraInput.close();

  // 释放预览输出流。
  await previewOutput.release();

  // 释放拍照输出流。
  await photoOutput.release();

  // 释放会话。
  await photoSession.release();

  // 会话置空。
  photoSession = undefined;
}
```