Android Open Source - GradleAndroid-App Camera Manager

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright (C) 2008 ZXing authors/*from   www.  ja v  a 2s .  co  m*/
 *
 * 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.android.app.function.qrcode.camera;

import java.io.IOException;

import android.content.Context;
import android.graphics.Point;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.os.Handler;
import android.util.Log;
import android.view.SurfaceHolder;

import com.android.app.function.qrcode.camera.open.OpenCameraInterface;

/**
 * This object wraps the Camera service object and expects to be the only one
 * talking to it. The implementation encapsulates the steps needed to take
 * preview-sized images, which are used for both preview and decoding.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public class CameraManager {

  private static final String TAG = CameraManager.class.getSimpleName();

  private final Context context;
  private final CameraConfigurationManager configManager;
  private Camera camera;
  private AutoFocusManager autoFocusManager;

  private boolean initialized;
  private boolean previewing;
  private int requestedCameraId = -1;
  /**
   * Preview frames are delivered here, which we pass on to the registered
   * handler. Make sure to clear the handler so it will only receive one
   * message.
   */
  private final PreviewCallback previewCallback;

  public CameraManager(Context context) {
    this.context = context;
    this.configManager = new CameraConfigurationManager(context);
    previewCallback = new PreviewCallback(configManager);
  }

  /**
   * Opens the camera driver and initializes the hardware parameters.
   * 
   * @param holder
   *            The surface object which the camera will draw preview frames
   *            into.
   * @throws java.io.IOException
   *             Indicates the camera driver failed to open.
   */
  public synchronized void openDriver(SurfaceHolder holder) throws IOException {
    Camera theCamera = camera;
    if (theCamera == null) {

      if (requestedCameraId >= 0) {
        theCamera = OpenCameraInterface.open(requestedCameraId);
      } else {
        theCamera = OpenCameraInterface.open();
      }

      if (theCamera == null) {
        throw new IOException();
      }
      camera = theCamera;
    }
    theCamera.setPreviewDisplay(holder);

    if (!initialized) {
      initialized = true;
      configManager.initFromCameraParameters(theCamera);
    }

    Camera.Parameters parameters = theCamera.getParameters();
    String parametersFlattened = parameters == null ? null : parameters.flatten(); // Save
                                            // these,
                                            // temporarily
    try {
      configManager.setDesiredCameraParameters(theCamera, false);
    } catch (RuntimeException re) {
      // Driver failed
      Log.w(TAG, "Camera rejected parameters. Setting only minimal safe-mode parameters");
      Log.i(TAG, "Resetting to saved camera params: " + parametersFlattened);
      // Reset:
      if (parametersFlattened != null) {
        parameters = theCamera.getParameters();
        parameters.unflatten(parametersFlattened);
        try {
          theCamera.setParameters(parameters);
          configManager.setDesiredCameraParameters(theCamera, true);
        } catch (RuntimeException re2) {
          // Well, darn. Give up
          Log.w(TAG, "Camera rejected even safe-mode parameters! No configuration");
        }
      }
    }

  }

  public synchronized boolean isOpen() {
    return camera != null;
  }

  /**
   * Closes the camera driver if still in use.
   */
  public synchronized void closeDriver() {
    if (camera != null) {
      camera.release();
      camera = null;
      // Make sure to clear these each time we close the camera, so that
      // any scanning rect
      // requested by intent is forgotten.
    }
  }

  /**
   * Asks the camera hardware to begin drawing preview frames to the screen.
   */
  public synchronized void startPreview() {
    Camera theCamera = camera;
    if (theCamera != null && !previewing) {
      theCamera.startPreview();
      previewing = true;
      autoFocusManager = new AutoFocusManager(context, camera);
    }
  }

  /**
   * Tells the camera to stop drawing preview frames.
   */
  public synchronized void stopPreview() {
    if (autoFocusManager != null) {
      autoFocusManager.stop();
      autoFocusManager = null;
    }
    if (camera != null && previewing) {
      camera.stopPreview();
      previewCallback.setHandler(null, 0);
      previewing = false;
    }
  }

  /**
   * A single preview frame will be returned to the handler supplied. The data
   * will arrive as byte[] in the message.obj field, with width and height
   * encoded as message.arg1 and message.arg2, respectively.
   * 
   * @param handler
   *            The handler to send the message to.
   * @param message
   *            The what field of the message to be sent.
   */
  public synchronized void requestPreviewFrame(Handler handler, int message) {
    Camera theCamera = camera;
    if (theCamera != null && previewing) {
      previewCallback.setHandler(handler, message);
      theCamera.setOneShotPreviewCallback(previewCallback);
    }
  }

  /**
   * Allows third party apps to specify the camera ID, rather than determine
   * it automatically based on available cameras and their orientation.
   * 
   * @param cameraId
   *            camera ID of the camera to use. A negative value means
   *            "no preference".
   */
  public synchronized void setManualCameraId(int cameraId) {
    requestedCameraId = cameraId;
  }

  /**
   * ?????????
   * 
   * @return
   */
  public Point getCameraResolution() {
    return configManager.getCameraResolution();
  }

  public Size getPreviewSize() {
    if (null != camera) {
      return camera.getParameters().getPreviewSize();
    }
    return null;
  }
}

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