/*
 * 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 <CoreGraphics/CoreGraphics.h>
#import "ZXBitArray.h"
#import "ZXBitMatrix.h"
#import "ZXLuminanceSource.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, 0 <= y < 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).
 */
- (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).
 */
- (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