/**
   * Get the largest possible zoom ratio (normalized to {@code 1.0f} and higher) that the camera can
   * support.
   *
   * <p>If the camera does not support zoom, it always returns {@code 1.0f}.
   *
   * @param params non-{@code null} camera api1 parameters
   * @return normalized max zoom ratio, at least {@code 1.0f}
   */
  public static float getMaxZoomRatio(Camera.Parameters params) {
    if (!params.isZoomSupported()) {
      return 1.0f; // no zoom
    }

    List<Integer> zoomRatios = params.getZoomRatios(); // sorted smallest->largest
    int zoom = zoomRatios.get(zoomRatios.size() - 1); // largest zoom ratio
    float zoomRatio = zoom * 1.0f / ZOOM_RATIO_MULTIPLIER; // normalize to 1.0 and smaller

    return zoomRatio;
  }
 public void zoom(int step) {
   Camera.Parameters parameters = mCamera.getParameters();
   if (!parameters.isZoomSupported()) return;
   int zoom = parameters.getZoom() + step;
   if (zoom > parameters.getMaxZoom()) zoom = parameters.getMaxZoom();
   else if (zoom < 0) zoom = 0;
   parameters.setZoom(zoom);
   String str = parameters.getZoomRatios().get(zoom) + "%";
   zoomText.setText(str);
   mCamera.setParameters(parameters);
 }
 @Override
 public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   boolean useFrontCamera = getArguments().getBoolean(FRONT_CAMERA, false);
   camera = getCameraInstance(useFrontCamera);
   if (camera == null) {
     return;
   }
   initScreenParams();
   parameters = camera.getParameters();
   zoomRatios = parameters.getZoomRatios();
   zoomIndex = minZoomIndex = 0;
   maxZoomIndex = parameters.getMaxZoom();
   previewSizes = buildPreviewSizesRatioMap(parameters.getSupportedPreviewSizes());
   pictureSizes = buildPictureSizesRatioMap(parameters.getSupportedPictureSizes());
   List<String> sceneModes = parameters.getSupportedSceneModes();
   if (sceneModes != null) {
     for (String mode : sceneModes) {
       if (mode.equals(Camera.Parameters.SCENE_MODE_HDR)) {
         supportedHDR = true;
         break;
       }
     }
   }
   // it returns false positive
   /*getActivity().getApplicationContext().getPackageManager()
   .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);*/
   List<String> flashModes = parameters.getSupportedFlashModes();
   if (flashModes == null || flashModes.size() <= 1) {
     /* Device has no flash */
     supportedFlash = false;
   } else {
     supportedFlash = true;
   }
   if (CameraConst.DEBUG) {
     Timber.d("PictureSizesRatioMap:");
     for (Ratio r : pictureSizes.keySet()) {
       Timber.d(r.toString() + ":");
       for (Quality q : pictureSizes.get(r).keySet()) {
         Camera.Size size = pictureSizes.get(r).get(q);
         if (size != null) {
           Timber.d(q.toString() + ": " + size.width + "x" + size.height);
         }
       }
     }
   }
   expandParams(getArguments());
   initParams();
 }
 private static Integer indexOfClosestZoom(Camera.Parameters parameters, double targetZoomRatio) {
   List<Integer> ratios = parameters.getZoomRatios();
   Log.i(TAG, "Zoom ratios: " + ratios);
   int maxZoom = parameters.getMaxZoom();
   if (ratios == null || ratios.isEmpty() || ratios.size() != maxZoom + 1) {
     Log.w(TAG, "Invalid zoom ratios!");
     return null;
   }
   double target100 = 100.0 * targetZoomRatio;
   double smallestDiff = Double.POSITIVE_INFINITY;
   int closestIndex = 0;
   for (int i = 0; i < ratios.size(); i++) {
     double diff = Math.abs(ratios.get(i) - target100);
     if (diff < smallestDiff) {
       smallestDiff = diff;
       closestIndex = i;
     }
   }
   Log.i(TAG, "Chose zoom ratio of " + (ratios.get(closestIndex) / 100.0));
   return closestIndex;
 }
  /**
   * Get the available 'crop' (zoom) rectangles for this camera.
   *
   * <p>When zoom is supported, this will return a list of {@code 1 + #getMaxZoom} size, where each
   * crop rectangle corresponds to a zoom ratio (and is centered at the middle).
   *
   * <p>Each crop rectangle is changed to have the same aspect ratio as {@code streamSize}, by
   * shrinking the rectangle if necessary.
   *
   * <p>To get the reported crop region when applying a zoom to the sensor, use {@code streamSize} =
   * {@code activeArray size}.
   *
   * @param params non-{@code null} camera api1 parameters
   * @param activeArray active array dimensions, in sensor space
   * @param streamSize stream size dimensions, in pixels
   * @return a list of available zoom rectangles, sorted from least zoomed to most zoomed
   */
  private static List<Rect> getAvailableCropRectangles(
      Camera.Parameters params, Rect activeArray, Size streamSize) {
    checkNotNull(params, "params must not be null");
    checkNotNull(activeArray, "activeArray must not be null");
    checkNotNull(streamSize, "streamSize must not be null");

    // TODO: change all uses of Rect activeArray to Size activeArray,
    // since we want the crop to be active-array relative, not pixel-array relative

    Rect unzoomedStreamCrop = getPreviewCropRectangleUnzoomed(activeArray, streamSize);

    if (!params.isZoomSupported()) {
      // Trivial case: No zoom -> only support the full size as the crop region
      return new ArrayList<>(Arrays.asList(unzoomedStreamCrop));
    }

    List<Rect> zoomCropRectangles = new ArrayList<>(params.getMaxZoom() + 1);
    Matrix scaleMatrix = new Matrix();
    RectF scaledRect = new RectF();

    for (int zoom : params.getZoomRatios()) {
      float shrinkRatio = ZOOM_RATIO_MULTIPLIER * 1.0f / zoom; // normalize to 1.0 and smaller

      // set scaledRect to unzoomedStreamCrop
      ParamsUtils.convertRectF(unzoomedStreamCrop, /*out*/ scaledRect);

      scaleMatrix.setScale(
          shrinkRatio, shrinkRatio, activeArray.exactCenterX(), activeArray.exactCenterY());

      scaleMatrix.mapRect(scaledRect);

      Rect intRect = ParamsUtils.createRect(scaledRect);

      // Round the rect corners towards the nearest integer values
      zoomCropRectangles.add(intRect);
    }

    return zoomCropRectangles;
  }