text: /*
   * Copyright 2009 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.google.zxing.multi;
  
  import com.google.zxing.BinaryBitmap;
  import com.google.zxing.DecodeHintType;
  import com.google.zxing.NotFoundException;
  import com.google.zxing.Reader;
  import com.google.zxing.ReaderException;
  import com.google.zxing.Result;
  import com.google.zxing.ResultPoint;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  /**
   * <p>Attempts to locate multiple barcodes in an image by repeatedly decoding portion of the image.
   * After one barcode is found, the areas left, above, right and below the barcode's
   * {@link ResultPoint}s are scanned, recursively.</p>
   *
   * <p>A caller may want to also employ {@link ByQuadrantReader} when attempting to find multiple
   * 2D barcodes, like QR Codes, in an image, where the presence of multiple barcodes might prevent
   * detecting any one of them.</p>
   *
   * <p>That is, instead of passing a {@link Reader} a caller might pass
   * {@code new ByQuadrantReader(reader)}.</p>
   *
   * @author Sean Owen
   */
  public final class GenericMultipleBarcodeReader implements MultipleBarcodeReader {
  
    private static final int MIN_DIMENSION_TO_RECUR = 100;
  
    private final Reader delegate;
  
    public GenericMultipleBarcodeReader(Reader delegate) {
      this.delegate = delegate;
    }
  
    @Override
    public Result[] decodeMultiple(BinaryBitmap image) throws NotFoundException {
      return decodeMultiple(image, null);
    }
  
    @Override
    public Result[] decodeMultiple(BinaryBitmap image, Map<DecodeHintType,?> hints)
        throws NotFoundException {
      List<Result> results = new ArrayList<Result>();
      doDecodeMultiple(image, hints, results, 0, 0);
      if (results.isEmpty()) {
        throw NotFoundException.getNotFoundInstance();
      }
      return results.toArray(new Result[results.size()]);
    }
  
    private void doDecodeMultiple(BinaryBitmap image,
                                  Map<DecodeHintType,?> hints,
                                  List<Result> results,
                                  int xOffset,
                                  int yOffset) {
      Result result;
      try {
        result = delegate.decode(image, hints);
      } catch (ReaderException re) {
        return;
      }
      boolean alreadyFound = false;
      for (Result existingResult : results) {
        if (existingResult.getText().equals(result.getText())) {
          alreadyFound = true;
          break;
        }
      }
      if (alreadyFound) {
        return;
      }
      results.add(translateResultPoints(result, xOffset, yOffset));
      ResultPoint[] resultPoints = result.getResultPoints();
      if (resultPoints == null || resultPoints.length == 0) {
        return;
      }
      int width = image.getWidth();
      int height = image.getHeight();
      float minX = width;
      float minY = height;
      float maxX = 0.0f;
      float maxY = 0.0f;
      for (ResultPoint point : resultPoints) {
        float x = point.getX();
        float y = point.getY();
        if (x < minX) {
          minX = x;
        }
        if (y < minY) {
          minY = y;
        }
        if (x > maxX) {
          maxX = x;
        }
        if (y > maxY) {
          maxY = y;
        }
      }
  
      // Decode left of barcode
      if (minX > MIN_DIMENSION_TO_RECUR) {
        doDecodeMultiple(image.crop(0, 0, (int) minX, height),
                         hints, results, xOffset, yOffset);
      }
      // Decode above barcode
      if (minY > MIN_DIMENSION_TO_RECUR) {
        doDecodeMultiple(image.crop(0, 0, width, (int) minY),
                         hints, results, xOffset, yOffset);
      }
      // Decode right of barcode
      if (maxX < width - MIN_DIMENSION_TO_RECUR) {
        doDecodeMultiple(image.crop((int) maxX, 0, width - (int) maxX, height),
                         hints, results, xOffset + (int) maxX, yOffset);
      }
      // Decode below barcode
      if (maxY < height - MIN_DIMENSION_TO_RECUR) {
        doDecodeMultiple(image.crop(0, (int) maxY, width, height - (int) maxY),
                         hints, results, xOffset, yOffset + (int) maxY);
      }
    }
  
    private static Result translateResultPoints(Result result, int xOffset, int yOffset) {
      ResultPoint[] oldResultPoints = result.getResultPoints();
      if (oldResultPoints == null) {
        return result;
      }
      ResultPoint[] newResultPoints = new ResultPoint[oldResultPoints.length];
      for (int i = 0; i < oldResultPoints.length; i++) {
        ResultPoint oldPoint = oldResultPoints[i];
        newResultPoints[i] = new ResultPoint(oldPoint.getX() + xOffset, oldPoint.getY() + yOffset);
      }
      return new Result(result.getText(), result.getRawBytes(), newResultPoints,
          result.getBarcodeFormat());
    }
  
  }
  