Android Open Source - geoar-app Camera View

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License

The source code is released under:

Apache License

Java Source Code

/**
 * Copyright 2012 52North Initiative for Geospatial Open Source Software GmbH
 */*ww w  .j ava 2  s .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 org.n52.geoar.tracking.camera;

import java.util.List;

import org.n52.geoar.R;

import android.app.AlertDialog;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Size;
import android.util.AttributeSet;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;
import android.view.WindowManager;

/**
 * A View which encapsulates a camera preview. Takes care of freeing all
 * resources as needed
 * 
 * @author Holger Hopmann
 * 
 */
public class CameraView extends SurfaceView implements Callback {

  private SurfaceHolder holder;
  private Camera camera;
  private int cameraId;
  private int cameraSizeHintWidth;
  private int cameraSizeHintHeight;

  public CameraView(Context context) {
    super(context);
    init();
  }

  public CameraView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  private void init() {
    holder = getHolder();
    holder.addCallback(this);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); // kept for
                                  // older
                                  // versions
  }

  /**
   * Methode ?bernommen aus Android API Demos, siehe
   * http://developer.android.com
   * /resources/samples/ApiDemos/src/com/example/android
   * /apis/graphics/CameraPreview.html
   * 
   * Copyright (C) 2007 The Android Open Source Project
   * 
   * @param sizes
   * @param w
   * @param h
   * @return
   */
  private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
    final double ASPECT_TOLERANCE = 0.05;
    double targetRatio = (double) w / h;
    if (sizes == null)
      return null;

    Size optimalSize = null;
    double minDiff = Double.MAX_VALUE;

    int targetHeight = h;

    // Try to find an size match aspect ratio and size
    for (Size size : sizes) {
      double ratio = (double) size.width / size.height;
      if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
        continue;
      if (Math.abs(size.height - targetHeight) < minDiff) {
        optimalSize = size;
        minDiff = Math.abs(size.height - targetHeight);
      }
    }

    // Cannot find the one match the aspect ratio, ignore the requirement
    if (optimalSize == null) {
      minDiff = Double.MAX_VALUE;
      for (Size size : sizes) {
        if (Math.abs(size.height - targetHeight) < minDiff) {
          optimalSize = size;
          minDiff = Math.abs(size.height - targetHeight);
        }
      }
    }
    return optimalSize;
  }

  public void surfaceChanged(SurfaceHolder holder, int format, int width,
      int height) {
    if (camera == null)
      return;
    // ?nderung des Surface f?r Kameravorschau ber?cksichtigen

    // Bilddrehung
    // Systemdienstinstanz erhalten
    WindowManager windowManager = (WindowManager) getContext()
        .getSystemService(Context.WINDOW_SERVICE);

    // Rotationskonstante Surface.ROTATION_...
    int rotation = windowManager.getDefaultDisplay().getRotation();

    // According to API Documentation
    // http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation%28int%29
    int degrees = 0;
    switch (rotation) {
    case Surface.ROTATION_0:
      degrees = 0;
      break;
    case Surface.ROTATION_90:
      degrees = 90;
      break;
    case Surface.ROTATION_180:
      degrees = 180;
      break;
    case Surface.ROTATION_270:
      degrees = 270;
      break;
    }

    // // Annahme, dass Kamera 90? verdreht zu Standardausrichtung
    // platziert
    // // ist. Tats?chlicher Wert erst ab Android 2.3 abrufbar. TODO
    // int cameraRotation = (90 - degrees + 360) % 360;
    CameraInfo info = new CameraInfo();
    Camera.getCameraInfo(cameraId, info);

    int cameraRotation;
    if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
      cameraRotation = (info.orientation + degrees) % 360;
      cameraRotation = (360 - cameraRotation) % 360; // compensate the
                              // mirror
    } else { // back-facing
      cameraRotation = (info.orientation - degrees + 360) % 360;
    }

    camera.stopPreview();  // Fix for 2.3.3 Bug?
    camera.setDisplayOrientation(cameraRotation);

    // Bildgr??e
    Camera.Parameters parameters = camera.getParameters();

    Size bestSize = getOptimalPreviewSize(
        parameters.getSupportedPreviewSizes(),
        cameraSizeHintWidth != 0 ? cameraSizeHintWidth : width,
        cameraSizeHintHeight != 0 ? cameraSizeHintHeight : height);
    parameters.setPreviewSize(bestSize.width, bestSize.height);

    // Update static camera settings fields
    if (cameraRotation == 0 || cameraRotation == 180) {
      RealityCamera.setViewportSize(bestSize);
      RealityCamera.setFovY(parameters.getVerticalViewAngle());
      // RealityCamera.setAspect(parameters.getHorizontalViewAngle()
      // / parameters.getVerticalViewAngle());
      // TODO merge updates
    } else {
      RealityCamera.setViewportSize(bestSize.height, bestSize.width);
      RealityCamera.setFovY(parameters.getHorizontalViewAngle());
      // RealityCamera.setAspect(parameters.getVerticalViewAngle()
      // / parameters.getHorizontalViewAngle());
      // TODO merge updates
    }
    camera.setParameters(parameters);
    // Neustart der Vorschaudarstellung
    camera.startPreview();

    requestLayout();
  }

  // @Override
  // protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  //
  // if (!RealityCamera.hasViewportSize()) {
  // super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  // } else {
  // int maxWidth = MeasureSpec.getSize(widthMeasureSpec);
  // // int maxHeight = MeasureSpec.getSize(heightMeasureSpec);
  //
  // float ratio = maxWidth / (float) RealityCamera.cameraViewportWidth;
  //
  // int widthSpec = MeasureSpec.makeMeasureSpec(maxWidth,
  // MeasureSpec.EXACTLY);
  // int heightSpec = MeasureSpec.makeMeasureSpec(
  // (int) (RealityCamera.cameraViewportHeight * ratio),
  // MeasureSpec.EXACTLY);
  //
  // setMeasuredDimension(widthSpec, heightSpec);
  // }
  // }

  public void surfaceCreated(SurfaceHolder holder) {
    try {
      // Kameraobjekt erzeugen
      int numCameras = Camera.getNumberOfCameras();
      CameraInfo cameraInfo = new CameraInfo();
      for (int i = 0; i < numCameras; i++) {
        Camera.getCameraInfo(i, cameraInfo);
        if (cameraInfo.facing == CameraInfo.CAMERA_FACING_BACK) {
          camera = Camera.open(i);
          cameraId = i;
          break;
        }
      }

      if (camera == null) {
        throw new RuntimeException(); // jump to exception block
      }

      camera.setPreviewDisplay(this.holder);
    } catch (Exception e) {
      new AlertDialog.Builder(getContext()).setTitle(R.string.error)
          .setMessage(R.string.camera_not_available)
          .setNeutralButton(R.string.ok, null).show();
    }
  }

  public void surfaceDestroyed(SurfaceHolder holder) {
    if (camera != null) {
      /** stop and release the camera */
      camera.stopPreview();
      camera.release();
      camera = null;
    }
  }

  @Override
  protected void onVisibilityChanged(View changedView, int visibility) {
    if (camera != null) {
      if (isShown()) {
        camera.startPreview();
      } else {
        camera.stopPreview();
      }
    }
    super.onVisibilityChanged(changedView, visibility);
  }

  public void setCameraSizeHint(int width, int height) {
    cameraSizeHintWidth = width;
    cameraSizeHintHeight = height;
  }

}

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