2 * Copyright 2009 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;
20 import com.google.zxing.common.BitMatrix;
23 * This class is the core bitmap class used by ZXing to represent 1 bit data. Reader objects
24 * accept a BinaryBitmap and attempt to decode it.
26 * @author dswitkin@google.com (Daniel Switkin)
28 public final class BinaryBitmap {
30 private final Binarizer binarizer;
31 private BitMatrix matrix;
33 public BinaryBitmap(Binarizer binarizer) {
34 if (binarizer == null) {
35 throw new IllegalArgumentException("Binarizer must be non-null.");
37 this.binarizer = binarizer;
42 * @return The width of the bitmap.
44 public int getWidth() {
45 return binarizer.getLuminanceSource().getWidth();
49 * @return The height of the bitmap.
51 public int getHeight() {
52 return binarizer.getLuminanceSource().getHeight();
56 * Converts one row of luminance data to 1 bit data. May actually do the conversion, or return
57 * cached data. Callers should assume this method is expensive and call it as seldom as possible.
58 * This method is intended for decoding 1D barcodes and may choose to apply sharpening.
60 * @param y The row to fetch, 0 <= y < bitmap height.
61 * @param row An optional preallocated array. If null or too small, it will be ignored.
62 * If used, the Binarizer will call BitArray.clear(). Always use the returned object.
63 * @return The array of bits for this row (true means black).
65 public BitArray getBlackRow(int y, BitArray row) throws ReaderException {
66 return binarizer.getBlackRow(y, row);
70 * Converts a 2D array of luminance data to 1 bit. As above, assume this method is expensive
71 * and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or
72 * may not apply sharpening. Therefore, a row from this matrix may not be identical to one
73 * fetched using getBlackRow(), so don't mix and match between them.
75 * @return The 2D array of bits for the image (true means black).
77 public BitMatrix getBlackMatrix() throws ReaderException {
78 // The matrix is created on demand the first time it is requested, then cached. There are two
80 // 1. This work will never be done if the caller only installs 1D Reader objects.
81 // 2. This work will only be done once even if the caller installs multiple 2D Readers.
83 matrix = binarizer.getBlackMatrix();
89 * @return Whether this bitmap can be cropped.
91 public boolean isCropSupported() {
92 return binarizer.getLuminanceSource().isCropSupported();
96 * Returns a new object with cropped image data. Implementations may keep a reference to the
97 * original data rather than a copy. Only callable if isCropSupported() is true.
99 * @param left The left coordinate, 0 <= left < getWidth().
100 * @param top The top coordinate, 0 <= top <= getHeight().
101 * @param width The width of the rectangle to crop.
102 * @param height The height of the rectangle to crop.
103 * @return A cropped version of this object.
105 public BinaryBitmap crop(int left, int top, int width, int height) {
106 LuminanceSource newSource = binarizer.getLuminanceSource().crop(left, top, width, height);
107 return new BinaryBitmap(binarizer.createBinarizer(newSource));
111 * @return Whether this bitmap supports counter-clockwise rotation.
113 public boolean isRotateSupported() {
114 return binarizer.getLuminanceSource().isRotateSupported();
118 * Returns a new object with rotated image data. Only callable if isRotateSupported() is true.
120 * @return A rotated version of this object.
122 public BinaryBitmap rotateCounterClockwise() {
123 LuminanceSource newSource = binarizer.getLuminanceSource().rotateCounterClockwise();
124 return new BinaryBitmap(binarizer.createBinarizer(newSource));
128 // These three methods are TEMPORARY and should be removed by the end of July 2009.
129 // They are only here so the transition from MonochromeBitmapSource to BinaryBitmap
130 // can be done in stages. We need to go through all the Reader objects and convert
131 // these calls to getBlackRow() and getBlackMatrix() at the top of this file.
133 // TIP: Replace calls to isBlack() with a single call to getBlackMatrix(), then call
134 // BitMatrix.get(x, y) per pixel.
135 public boolean isBlack(int x, int y) throws ReaderException {
136 if (matrix == null) {
137 matrix = binarizer.getBlackMatrix();
139 return matrix.get(x, y);
144 // TIP: 2D Readers should replace uses of this method with a single call to getBlackMatrix(),
145 // then perform random access on that BitMatrix as needed. The version of getBlackRow() with
146 // two arguments is only meant for 1D Readers, which I've already converted.
147 public BitArray getBlackRow(int y, BitArray row, int startX, int getWidth)
148 throws ReaderException {
149 if (row == null || row.getSize() < getWidth) {
150 row = new BitArray(getWidth);
155 if (matrix == null) {
156 matrix = binarizer.getBlackMatrix();
158 for (int x = 0; x < getWidth; x++) {
159 if (matrix.get(startX + x, y)) {
168 // TIP: Replace calls to getBlackColumn() with a single call to getBlackMatrix(), then
169 // perform random access on that BitMatrix as needed.
170 public BitArray getBlackColumn(int x, BitArray column, int startY, int getHeight)
171 throws ReaderException {
172 if (column == null || column.getSize() < getHeight) {
173 column = new BitArray(getHeight);
178 if (matrix == null) {
179 matrix = binarizer.getBlackMatrix();
181 for (int y = 0; y < getHeight; y++) {
182 if (matrix.get(x, startY + y)) {