text: /*
   * Copyright 2012 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.
   */
  
  #import "ZXBitArray.h"
  #import "ZXBitMatrix.h"
  #import "ZXLuminanceSource.h"
  #import <CoreGraphics/CoreGraphics.h>
  
  /**
   * 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.
   */
  @interface ZXBinarizer : NSObject
  
  @property (nonatomic, strong, readonly) ZXLuminanceSource *luminanceSource;
  @property (nonatomic, assign, readonly) int width;
  @property (nonatomic, assign, readonly) int height;
  
  - (id)initWithSource:(ZXLuminanceSource *)source;
  + (id)binarizerWithSource:(ZXLuminanceSource *)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 ZXBitArray clear. Always use the returned object.
   * @return The array of bits for this row (true means black) or nil if row can't be binarized.
   */
  - (ZXBitArray *)blackRow:(int)y row:(ZXBitArray *)row error:(NSError **)error;
  
  /**
   * 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) or nil if image can't be binarized
   * to make a matrix.
   */
  - (ZXBitMatrix *)blackMatrixWithError:(NSError **)error;
  
  /**
   * 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.
   */
  - (ZXBinarizer *)createBinarizer:(ZXLuminanceSource *)source;
  
  - (CGImageRef)createImage CF_RETURNS_RETAINED;
  
  @end
  