content: /*
   * 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.ailiwean.core.zxing.core;
  
  import com.ailiwean.core.zxing.core.common.BitArray;
  import com.ailiwean.core.zxing.core.common.BitMatrix;
  
  /**
   * This class hierarchy provides a set of methods to convert luminance data to 1 bit data.
   * It allows the algorithm to vary polymorphically, for example allowing a very expensive
   * thresholding technique for servers and a fast one for mobile. It also permits the implementation
   * to vary, e.g. a JNI version for Android and a Java fallback version for other platforms.
   *
   * @author dswitkin@google.com (Daniel Switkin)
   */
  public abstract class Binarizer {
  
    private final LuminanceSource source;
  
    protected Binarizer(LuminanceSource source) {
      this.source = source;
    }
  
    public final LuminanceSource getLuminanceSource() {
      return source;
    }
  
    /**
     * Converts one row of luminance data to 1 bit data. May actually do the conversion, or return
     * cached data. Callers should assume this method is expensive and call it as seldom as possible.
     * This method is intended for decoding 1D barcodes and may choose to apply sharpening.
     * For callers which only examine one row of pixels at a time, the same BitArray should be reused
     * and passed in with each call for performance. However it is legal to keep more than one row
     * at a time if needed.
     *
     * @param y The row to fetch, which must be in [0, bitmap height)
     * @param row An optional preallocated array. If null or too small, it will be ignored.
     *            If used, the Binarizer will call BitArray.clear(). Always use the returned object.
     * @return The array of bits for this row (true means black).
     * @throws NotFoundException if row can't be binarized
     */
    public abstract BitArray getBlackRow(int y, BitArray row) throws NotFoundException;
  
    /**
     * Converts a 2D array of luminance data to 1 bit data. As above, assume this method is expensive
     * and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or
     * may not apply sharpening. Therefore, a row from this matrix may not be identical to one
     * fetched using getBlackRow(), so don't mix and match between them.
     *
     * @return The 2D array of bits for the image (true means black).
     * @throws NotFoundException if image can't be binarized to make a matrix
     */
    public abstract BitMatrix getBlackMatrix() throws NotFoundException;
  
    /**
     * Creates a new object with the same type as this Binarizer implementation, but with pristine
     * state. This is needed because Binarizer implementations may be stateful, e.g. keeping a cache
     * of 1 bit data. See Effective Java for why we can't use Java's clone() method.
     *
     * @param source The LuminanceSource this Binarizer will operate on.
     * @return A new concrete Binarizer implementation object.
     */
    public abstract Binarizer createBinarizer(LuminanceSource source);
  
    public final int getWidth() {
      return source.getWidth();
    }
  
    public final int getHeight() {
      return source.getHeight();
    }
  
  }
  