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.common.ByteMatrix;
22 import com.google.zxing.qrcode.encoder.ByteArray;
23 import com.google.zxing.qrcode.encoder.Encoder;
24 import com.google.zxing.qrcode.encoder.QRCode;
26 import java.util.Hashtable;
28 public final class QRCodeWriter implements Writer {
30 public ByteMatrix encode(byte[] contents, BarcodeFormat format, int width,
31 int height) throws Exception {
33 return encode(contents, format, width, height, null);
36 public ByteMatrix encode(byte[] contents, BarcodeFormat format, int width, int height,
37 Hashtable hints) throws Exception {
39 if (contents == null || contents.length == 0) {
40 throw new IllegalArgumentException("Found empty contents");
43 if (format != BarcodeFormat.QR_CODE) {
44 throw new IllegalArgumentException("Can only encode QR_CODE, but got " + format);
47 if (width < 0 || height < 0) {
48 throw new IllegalArgumentException("Requested dimensions are too small: " + width + "x" +
52 // TODO: Check hints for error correction level instead of hardcoding
53 int errorCorrectionLevel = QRCode.EC_LEVEL_L;
54 QRCode code = new QRCode();
55 if (Encoder.Encode(new ByteArray(contents), errorCorrectionLevel, code)) {
56 return renderResult(code, width, height);
58 throw new IllegalStateException("Could not generate a QR Code");
62 // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
63 // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
64 private ByteMatrix renderResult(QRCode code, final int width, final int height) {
65 ByteMatrix input = code.matrix();
66 int inputWidth = input.width();
67 int inputHeight = input.height();
68 int outputWidth = Math.max(width, inputWidth);
69 int outputHeight = Math.max(height, inputHeight);
71 int multiple = Math.min(outputWidth / inputWidth, outputHeight / inputHeight);
72 int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
73 int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
75 ByteMatrix output = new ByteMatrix(outputHeight, outputWidth);
76 byte[][] outputArray = output.getArray();
78 // We could be tricky and use the first row in each set of multiple as the temporary storage,
79 // instead of allocating this separate array.
80 byte[] row = new byte[outputWidth];
82 // 1. Write the white lines at the top
83 for (int y = 0; y < topPadding; y++) {
84 setRowColor(outputArray[y], (byte) 255);
87 // 2. Expand the QR image to the multiple
88 final byte[][] inputArray = input.getArray();
89 for (int y = 0; y < inputHeight; y++) {
90 // a. Write the white pixels at the left of each row
91 for (int x = 0; x < leftPadding; x++) {
95 // b. Write the contents of this row of the barcode
96 int offset = leftPadding;
97 for (int x = 0; x < inputWidth; x++) {
98 byte value = (inputArray[y][x] == 1) ? 0 : (byte) 255;
99 for (int z = 0; z < multiple; z++) {
100 row[offset + z] = value;
105 // c. Write the white pixels at the right of each row
106 offset = leftPadding + (inputWidth * multiple);
107 for (int x = offset; x < outputWidth; x++) {
111 // d. Write the completed row multiple times
112 offset = topPadding + (y * multiple);
113 for (int z = 0; z < multiple; z++) {
114 System.arraycopy(row, 0, outputArray[offset + z], 0, outputWidth);
118 // 3. Write the white lines at the bottom
119 int offset = topPadding + (inputHeight * multiple);
120 for (int y = offset; y < outputHeight; y++) {
121 setRowColor(outputArray[y], (byte) 255);
127 private static void setRowColor(byte[] row, byte value) {
128 for (int x = 0; x < row.length; x++) {