content: /*
   * Copyright (C) 2012 ZXing authors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.xys.libzxing.zxing.camera.open;
  
  import android.hardware.Camera;
  import android.util.Log;
  
  public class OpenCameraInterface {
  
      private static final String TAG = OpenCameraInterface.class.getName();
  
      /**
       * Opens the requested camera with {@link Camera#open(int)}, if one exists.
       *
       * @param cameraId camera ID of the camera to use. A negative value means
       *                 "no preference"
       * @return handle to {@link Camera} that was opened
       */
      public static Camera open(int cameraId) {
  
          int numCameras = Camera.getNumberOfCameras();
          if (numCameras == 0) {
              Log.w(TAG, "No cameras!");
              return null;
          }
  
          boolean explicitRequest = cameraId >= 0;
  
          if (!explicitRequest) {
              // Select a camera if no explicit camera requested
              int index = 0;
              while (index < numCameras) {
                  Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
                  Camera.getCameraInfo(index, cameraInfo);
                  if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
                      break;
                  }
                  index++;
              }
  
              cameraId = index;
          }
  
          Camera camera;
          if (cameraId < numCameras) {
              Log.i(TAG, "Opening camera #" + cameraId);
              camera = Camera.open(cameraId);
          } else {
              if (explicitRequest) {
                  Log.w(TAG, "Requested camera does not exist: " + cameraId);
                  camera = null;
              } else {
                  Log.i(TAG, "No camera facing back; returning camera #0");
                  camera = Camera.open(0);
              }
          }
  
          return camera;
      }
  
      /**
       * Opens a rear-facing camera with {@link Camera#open(int)}, if one exists,
       * or opens camera 0.
       *
       * @return handle to {@link Camera} that was opened
       */
      public static Camera open() {
          return open(-1);
      }
  
  }
  