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.Writer;
21 import com.google.zxing.WriterException;
22 import com.google.zxing.common.ByteMatrix;
23 import com.google.zxing.common.ByteArray;
24 import com.google.zxing.qrcode.encoder.Encoder;
25 import com.google.zxing.qrcode.encoder.QRCode;
27 import java.util.Hashtable;
30 * This object renders a QR Code as a ByteMatrix 2D array of greyscale values.
32 * @author dswitkin@google.com (Daniel Switkin)
34 public final class QRCodeWriter implements Writer {
36 private static final int QUIET_ZONE_SIZE = 4;
38 public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height)
39 throws WriterException {
41 return encode(contents, format, width, height, null);
44 public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height,
45 Hashtable hints) throws WriterException {
47 if (contents == null || contents.length() == 0) {
48 throw new IllegalArgumentException("Found empty contents");
51 if (format != BarcodeFormat.QR_CODE) {
52 throw new IllegalArgumentException("Can only encode QR_CODE, but got " + format);
55 if (width < 0 || height < 0) {
56 throw new IllegalArgumentException("Requested dimensions are too small: " + width + "x" +
60 // TODO: Check hints for error correction level instead of hardcoding
61 int errorCorrectionLevel = QRCode.EC_LEVEL_L;
62 QRCode code = new QRCode();
63 Encoder.Encode(new ByteArray(contents), errorCorrectionLevel, code);
64 return renderResult(code, width, height);
67 // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
68 // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
69 private ByteMatrix renderResult(QRCode code, final int width, final int height) {
70 ByteMatrix input = code.matrix();
71 int inputWidth = input.width();
72 int inputHeight = input.height();
73 int qrWidth = inputWidth + (QUIET_ZONE_SIZE * 2);
74 int qrHeight = inputHeight + (QUIET_ZONE_SIZE * 2);
75 int outputWidth = Math.max(width, qrWidth);
76 int outputHeight = Math.max(height, qrHeight);
78 int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);
79 // Padding includes both the quiet zone and the extra white pixels to accomodate the requested
80 // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
81 // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
82 // handle all the padding from 100x100 (the actual QR) up to 200x160.
83 int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
84 int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
86 ByteMatrix output = new ByteMatrix(outputHeight, outputWidth);
87 byte[][] outputArray = output.getArray();
89 // We could be tricky and use the first row in each set of multiple as the temporary storage,
90 // instead of allocating this separate array.
91 byte[] row = new byte[outputWidth];
93 // 1. Write the white lines at the top
94 for (int y = 0; y < topPadding; y++) {
95 setRowColor(outputArray[y], (byte) 255);
98 // 2. Expand the QR image to the multiple
99 final byte[][] inputArray = input.getArray();
100 for (int y = 0; y < inputHeight; y++) {
101 // a. Write the white pixels at the left of each row
102 for (int x = 0; x < leftPadding; x++) {
106 // b. Write the contents of this row of the barcode
107 int offset = leftPadding;
108 for (int x = 0; x < inputWidth; x++) {
109 byte value = (inputArray[y][x] == 1) ? 0 : (byte) 255;
110 for (int z = 0; z < multiple; z++) {
111 row[offset + z] = value;
116 // c. Write the white pixels at the right of each row
117 offset = leftPadding + (inputWidth * multiple);
118 for (int x = offset; x < outputWidth; x++) {
122 // d. Write the completed row multiple times
123 offset = topPadding + (y * multiple);
124 for (int z = 0; z < multiple; z++) {
125 System.arraycopy(row, 0, outputArray[offset + z], 0, outputWidth);
129 // 3. Write the white lines at the bottom
130 int offset = topPadding + (inputHeight * multiple);
131 for (int y = offset; y < outputHeight; y++) {
132 setRowColor(outputArray[y], (byte) 255);
138 private static void setRowColor(byte[] row, byte value) {
139 for (int x = 0; x < row.length; x++) {