2 * Copyright 2007 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing;
19 import com.google.zxing.common.BitArray;
22 * <p>Encapsulates a generic black-and-white bitmap -- a collection of pixels in two dimensions.
23 * This unifies many possible representations, like AWT's <code>BufferedImage</code>.</p>
25 * @author srowen@google.com (Sean Owen)
27 public interface MonochromeBitmapSource {
30 * @param x horizontal offset, from left, of the pixel
31 * @param y vertical offset, from top, of the pixel
32 * @return true iff the pixel at (x,y) is black
34 boolean isBlack(int x, int y);
37 * <p>Returns an entire row of black/white pixels as an array of bits, where "true" means "black".
38 * This is a sort of "bulk get" operation intended to enable efficient access in
39 * certain situations.</p>
41 * @param y vertical offset, from top, of the row of pixels
42 * @param row if not null, {@link BitArray} to write pixels into. If null, a new {@link BitArray}
43 * is allocated and returned.
44 * @param startX horizontal offset, from left, from which to start getting pixels
45 * @param getWidth number of pixels to get from the row
46 * @return {@link BitArray} representing the (subset of the) row of pixels. If row parameter
47 * was not null, it is returned.
49 BitArray getBlackRow(int y, BitArray row, int startX, int getWidth);
52 * @return height of underlying image
57 * @return width of underlying image
62 * Retrieves the luminance at the pixel x,y in the bitmap. This method is only used for estimating
63 * the black point and implementing getBlackRow() - it is not meant for decoding.
65 * @param x The x coordinate in the image.
66 * @param y The y coordinate in the image.
67 * @return The luminance value between 0 and 255.
69 int getLuminance(int x, int y);
72 * Some implementations can be much more efficient by fetching an entire row of luminance data at
73 * a time. This method should be called once per row before calling getLuminance().
75 * @param y The row to cache.
77 void cacheRowForLuminance(int y);
80 * <p>Estimates black point according to the given method, which is optionally parameterized by
81 * a single int argument. For {@link BlackPointEstimationMethod#ROW_SAMPLING}, this
82 * specifies the row to sample.</p>
84 * <p>The estimated value will be used in subsequent computations that rely on an estimated black
87 * @param method black point estimation method
88 * @param argument method-specific argument
90 void estimateBlackPoint(BlackPointEstimationMethod method, int argument) throws ReaderException;
93 * @return {@link BlackPointEstimationMethod} representing last sampling method used
95 BlackPointEstimationMethod getLastEstimationMethod();
98 * <p>Optional operation which returns an implementation based on the same underlying
99 * image, but which behaves as if the underlying image had been rotated 90 degrees
100 * counterclockwise. This is useful in the context of 1D barcodes and the
101 * {@link DecodeHintType#TRY_HARDER} decode hint, and is only intended to be
102 * used in non-resource-constrained environments. Hence, implementations
103 * of this class which are only used in resource-constrained mobile environments
104 * don't have a need to implement this.</p>
106 * @throws IllegalArgumentException if not supported
108 MonochromeBitmapSource rotateCounterClockwise();
111 * @return true iff rotation is supported
112 * @see #rotateCounterClockwise()
114 boolean isRotateSupported();