2 * Copyright 2008 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.qrcode;
19 import com.google.zxing.BarcodeFormat;
20 import com.google.zxing.EncodeHintType;
21 import com.google.zxing.Writer;
22 import com.google.zxing.WriterException;
23 import com.google.zxing.common.ByteArray;
24 import com.google.zxing.common.ByteMatrix;
25 import com.google.zxing.qrcode.encoder.Encoder;
26 import com.google.zxing.qrcode.encoder.QRCode;
28 import java.util.Hashtable;
31 * This object renders a QR Code as a ByteMatrix 2D array of greyscale values.
33 * @author dswitkin@google.com (Daniel Switkin)
35 public final class QRCodeWriter implements Writer {
37 private static final int QUIET_ZONE_SIZE = 4;
39 public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height)
40 throws WriterException {
42 return encode(contents, format, width, height, null);
45 public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height,
46 Hashtable hints) throws WriterException {
48 if (contents == null || contents.length() == 0) {
49 throw new IllegalArgumentException("Found empty contents");
52 if (format != BarcodeFormat.QR_CODE) {
53 throw new IllegalArgumentException("Can only encode QR_CODE, but got " + format);
56 if (width < 0 || height < 0) {
57 throw new IllegalArgumentException("Requested dimensions are too small: " + width + "x" +
61 int errorCorrectionLevel = QRCode.EC_LEVEL_L;
63 Integer requestedECLevel = (Integer) hints.get(EncodeHintType.ERROR_CORRECTION);
64 if (requestedECLevel != null) {
65 errorCorrectionLevel = requestedECLevel.intValue();
69 QRCode code = new QRCode();
70 Encoder.Encode(new ByteArray(contents), errorCorrectionLevel, code);
71 return renderResult(code, width, height);
74 // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
75 // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
76 private ByteMatrix renderResult(QRCode code, final int width, final int height) {
77 ByteMatrix input = code.matrix();
78 int inputWidth = input.width();
79 int inputHeight = input.height();
80 int qrWidth = inputWidth + (QUIET_ZONE_SIZE * 2);
81 int qrHeight = inputHeight + (QUIET_ZONE_SIZE * 2);
82 int outputWidth = Math.max(width, qrWidth);
83 int outputHeight = Math.max(height, qrHeight);
85 int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);
86 // Padding includes both the quiet zone and the extra white pixels to accomodate the requested
87 // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
88 // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
89 // handle all the padding from 100x100 (the actual QR) up to 200x160.
90 int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
91 int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
93 ByteMatrix output = new ByteMatrix(outputHeight, outputWidth);
94 byte[][] outputArray = output.getArray();
96 // We could be tricky and use the first row in each set of multiple as the temporary storage,
97 // instead of allocating this separate array.
98 byte[] row = new byte[outputWidth];
100 // 1. Write the white lines at the top
101 for (int y = 0; y < topPadding; y++) {
102 setRowColor(outputArray[y], (byte) 255);
105 // 2. Expand the QR image to the multiple
106 final byte[][] inputArray = input.getArray();
107 for (int y = 0; y < inputHeight; y++) {
108 // a. Write the white pixels at the left of each row
109 for (int x = 0; x < leftPadding; x++) {
113 // b. Write the contents of this row of the barcode
114 int offset = leftPadding;
115 for (int x = 0; x < inputWidth; x++) {
116 byte value = (inputArray[y][x] == 1) ? 0 : (byte) 255;
117 for (int z = 0; z < multiple; z++) {
118 row[offset + z] = value;
123 // c. Write the white pixels at the right of each row
124 offset = leftPadding + (inputWidth * multiple);
125 for (int x = offset; x < outputWidth; x++) {
129 // d. Write the completed row multiple times
130 offset = topPadding + (y * multiple);
131 for (int z = 0; z < multiple; z++) {
132 System.arraycopy(row, 0, outputArray[offset + z], 0, outputWidth);
136 // 3. Write the white lines at the bottom
137 int offset = topPadding + (inputHeight * multiple);
138 for (int y = offset; y < outputHeight; y++) {
139 setRowColor(outputArray[y], (byte) 255);
145 private static void setRowColor(byte[] row, byte value) {
146 for (int x = 0; x < row.length; x++) {