| /* |
| * 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; |
| |
| import com.google.zxing.common.BitArray; |
| import com.google.zxing.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(); |
| } |
| |
| } |