Android Open Source - ZXingFragment Decode Task

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License

The source code is released under:

Apache License

Java Source Code

package de.klimek.zxingfragment;
//from  www . ja  v  a2 s . c  o  m
import android.graphics.Rect;
import android.hardware.Camera;
import android.os.AsyncTask;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.PlanarYUVLuminanceSource;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;

class DecodeTask extends AsyncTask<byte[], Void, Result> {
  private Decoder mDecoder;
  private Camera mCamera;
  private int mCameraDisplayOrientation = 0;
  private MultiFormatReader mMultiFormatReader = new MultiFormatReader();

  public DecodeTask(Decoder decoder, Camera camera,
      int cameraDisplayOrientation) {
    mDecoder = decoder;
    mCamera = camera;
    mCameraDisplayOrientation = cameraDisplayOrientation;
  }

  @Override
  protected Result doInBackground(byte[]... datas) {
    return getResult(datas[0], mCamera, mCameraDisplayOrientation,
        mMultiFormatReader);
  }

  @Override
  protected void onPostExecute(Result result) {
    if (result != null) {
      mDecoder.onDecodeSuccess(result.toString());
    } else {
      mDecoder.onDecodeFail();
    }
  }

  private static Result getResult(byte[] data, Camera camera,
      int cameraDisplayOrientation, MultiFormatReader reader) {
    Camera.Size previewSize = camera.getParameters().getPreviewSize();

    Rect boundingRect = getBoundingRect(previewSize,
        cameraDisplayOrientation);
    PlanarYUVLuminanceSource source = buildLuminanceSource(data,
        previewSize, boundingRect, cameraDisplayOrientation);
    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

    try {
      return reader.decodeWithState(bitmap);
    } catch (NotFoundException e) {
      return null;
    } finally {
      reader.reset();
    }
  }

  private static PlanarYUVLuminanceSource buildLuminanceSource(byte[] data,
      Camera.Size previewSize, Rect boundingRect,
      int cameraDisplayOrientation) {

    switch (cameraDisplayOrientation) {
    case 0:
      // data = flip(data);
      break;

    case 90:
      rotate90(data, previewSize.width, previewSize.height);
      return new PlanarYUVLuminanceSource(data, previewSize.height,
          previewSize.width, boundingRect.top, boundingRect.left,
          boundingRect.height(), boundingRect.width(), false);
    case 180:
      break;

    case 270:
      rotate90(data, previewSize.width, previewSize.height);
      break;
    }

    return new PlanarYUVLuminanceSource(data, previewSize.width,
        previewSize.height, boundingRect.left, boundingRect.top,
        boundingRect.width(), boundingRect.height(), false);
  }

  private static Rect getBoundingRect(Camera.Size previewSize,
      int cameraDisplayOrientation) {
    double heightFraction = Decoder.BOUNDS_FRACTION;
    double widthFraction = Decoder.BOUNDS_FRACTION;
    if (cameraDisplayOrientation == 90 || cameraDisplayOrientation == 270) {
      widthFraction = Decoder.VERTICAL_HEIGHT_FRACTION;
    }
    int height = (int) (previewSize.height * heightFraction);
    int width = (int) (previewSize.width * widthFraction);
    int left = (int) (previewSize.width * ((1 - widthFraction) / 2));
    int top = (int) (previewSize.height * ((1 - heightFraction) / 2));
    int right = left + width;
    int bottom = top + height;
    return new Rect(left, top, right, bottom);
  }

  private static void rotate90(byte[] data, int width, int height) {
    int length = height * width;
    int lengthDec = length - 1;
    int i = 0;
    do {
      int k = (i * height) % lengthDec;
      while (k > i)
        k = (height * k) % lengthDec;
      if (k != i)
        swap(data, k, i);
    } while (++i <= (length - 2));
  }

  private static void swap(byte[] data, int k, int i) {
    byte temp = data[k];
    data[k] = data[i];
    data[i] = temp;
  }
}

Java Source Code List

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