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;
27 import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
29 import java.util.Hashtable;
32 * This object renders a QR Code as a ByteMatrix 2D array of greyscale values.
34 * @author dswitkin@google.com (Daniel Switkin)
36 public final class QRCodeWriter implements Writer {
38 private static final int QUIET_ZONE_SIZE = 4;
40 public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height)
41 throws WriterException {
43 return encode(contents, format, width, height, null);
46 public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height,
47 Hashtable hints) throws WriterException {
49 if (contents == null || contents.length() == 0) {
50 throw new IllegalArgumentException("Found empty contents");
53 if (format != BarcodeFormat.QR_CODE) {
54 throw new IllegalArgumentException("Can only encode QR_CODE, but got " + format);
57 if (width < 0 || height < 0) {
58 throw new IllegalArgumentException("Requested dimensions are too small: " + width + "x" +
62 ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.L;
64 ErrorCorrectionLevel requestedECLevel = (ErrorCorrectionLevel) hints.get(EncodeHintType.ERROR_CORRECTION);
65 if (requestedECLevel != null) {
66 errorCorrectionLevel = requestedECLevel;
70 QRCode code = new QRCode();
71 Encoder.encode(contents, errorCorrectionLevel, code);
72 return renderResult(code, width, height);
75 // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
76 // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
77 private ByteMatrix renderResult(QRCode code, final int width, final int height) {
78 ByteMatrix input = code.getMatrix();
79 int inputWidth = input.width();
80 int inputHeight = input.height();
81 int qrWidth = inputWidth + (QUIET_ZONE_SIZE * 2);
82 int qrHeight = inputHeight + (QUIET_ZONE_SIZE * 2);
83 int outputWidth = Math.max(width, qrWidth);
84 int outputHeight = Math.max(height, qrHeight);
86 int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);
87 // Padding includes both the quiet zone and the extra white pixels to accomodate the requested
88 // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
89 // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
90 // handle all the padding from 100x100 (the actual QR) up to 200x160.
91 int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
92 int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
94 ByteMatrix output = new ByteMatrix(outputHeight, outputWidth);
95 byte[][] outputArray = output.getArray();
97 // We could be tricky and use the first row in each set of multiple as the temporary storage,
98 // instead of allocating this separate array.
99 byte[] row = new byte[outputWidth];
101 // 1. Write the white lines at the top
102 for (int y = 0; y < topPadding; y++) {
103 setRowColor(outputArray[y], (byte) 255);
106 // 2. Expand the QR image to the multiple
107 final byte[][] inputArray = input.getArray();
108 for (int y = 0; y < inputHeight; y++) {
109 // a. Write the white pixels at the left of each row
110 for (int x = 0; x < leftPadding; x++) {
114 // b. Write the contents of this row of the barcode
115 int offset = leftPadding;
116 for (int x = 0; x < inputWidth; x++) {
117 byte value = (inputArray[y][x] == 1) ? 0 : (byte) 255;
118 for (int z = 0; z < multiple; z++) {
119 row[offset + z] = value;
124 // c. Write the white pixels at the right of each row
125 offset = leftPadding + (inputWidth * multiple);
126 for (int x = offset; x < outputWidth; x++) {
130 // d. Write the completed row multiple times
131 offset = topPadding + (y * multiple);
132 for (int z = 0; z < multiple; z++) {
133 System.arraycopy(row, 0, outputArray[offset + z], 0, outputWidth);
137 // 3. Write the white lines at the bottom
138 int offset = topPadding + (inputHeight * multiple);
139 for (int y = offset; y < outputHeight; y++) {
140 setRowColor(outputArray[y], (byte) 255);
146 private static void setRowColor(byte[] row, byte value) {
147 for (int x = 0; x < row.length; x++) {