001/*
002 * Copyright 2008 ZXing authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.itextpdf.text.pdf.qrcode;
018
019
020import java.util.Map;
021
022/**
023 * This object renders a QR Code as a ByteMatrix 2D array of greyscale values.
024 *
025 * @author dswitkin@google.com (Daniel Switkin)
026 * @since 5.0.2
027 */
028public final class QRCodeWriter {
029
030  private static final int QUIET_ZONE_SIZE = 4;
031
032  public ByteMatrix encode(String contents, int width, int height)
033      throws WriterException {
034
035    return encode(contents, width, height, null);
036  }
037
038  public ByteMatrix encode(String contents, int width, int height,
039      Map<EncodeHintType,Object> hints) throws WriterException {
040
041    if (contents == null || contents.length() == 0) {
042      throw new IllegalArgumentException("Found empty contents");
043    }
044
045    if (width < 0 || height < 0) {
046      throw new IllegalArgumentException("Requested dimensions are too small: " + width + 'x' +
047          height);
048    }
049
050    ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.L;
051    if (hints != null) {
052      ErrorCorrectionLevel requestedECLevel = (ErrorCorrectionLevel) hints.get(EncodeHintType.ERROR_CORRECTION);
053      if (requestedECLevel != null) {
054        errorCorrectionLevel = requestedECLevel;
055      }
056    }
057
058    QRCode code = new QRCode();
059    Encoder.encode(contents, errorCorrectionLevel, hints, code);
060    return renderResult(code, width, height);
061  }
062
063  // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
064  // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
065  private static ByteMatrix renderResult(QRCode code, int width, int height) {
066    ByteMatrix input = code.getMatrix();
067    int inputWidth = input.getWidth();
068    int inputHeight = input.getHeight();
069    int qrWidth = inputWidth + (QUIET_ZONE_SIZE << 1);
070    int qrHeight = inputHeight + (QUIET_ZONE_SIZE << 1);
071    int outputWidth = Math.max(width, qrWidth);
072    int outputHeight = Math.max(height, qrHeight);
073
074    int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);
075    // Padding includes both the quiet zone and the extra white pixels to accommodate the requested
076    // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
077    // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
078    // handle all the padding from 100x100 (the actual QR) up to 200x160.
079    int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
080    int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
081
082    ByteMatrix output = new ByteMatrix(outputWidth, outputHeight);
083    byte[][] outputArray = output.getArray();
084
085    // We could be tricky and use the first row in each set of multiple as the temporary storage,
086    // instead of allocating this separate array.
087    byte[] row = new byte[outputWidth];
088
089    // 1. Write the white lines at the top
090    for (int y = 0; y < topPadding; y++) {
091      setRowColor(outputArray[y], (byte) 255);
092    }
093
094    // 2. Expand the QR image to the multiple
095    byte[][] inputArray = input.getArray();
096    for (int y = 0; y < inputHeight; y++) {
097      // a. Write the white pixels at the left of each row
098      for (int x = 0; x < leftPadding; x++) {
099        row[x] = (byte) 255;
100      }
101
102      // b. Write the contents of this row of the barcode
103      int offset = leftPadding;
104      for (int x = 0; x < inputWidth; x++) {
105        byte value = (inputArray[y][x] == 1) ? 0 : (byte) 255;
106        for (int z = 0; z < multiple; z++) {
107          row[offset + z] = value;
108        }
109        offset += multiple;
110      }
111
112      // c. Write the white pixels at the right of each row
113      offset = leftPadding + (inputWidth * multiple);
114      for (int x = offset; x < outputWidth; x++) {
115        row[x] = (byte) 255;
116      }
117
118      // d. Write the completed row multiple times
119      offset = topPadding + (y * multiple);
120      for (int z = 0; z < multiple; z++) {
121        System.arraycopy(row, 0, outputArray[offset + z], 0, outputWidth);
122      }
123    }
124
125    // 3. Write the white lines at the bottom
126    int offset = topPadding + (inputHeight * multiple);
127    for (int y = offset; y < outputHeight; y++) {
128      setRowColor(outputArray[y], (byte) 255);
129    }
130
131    return output;
132  }
133
134  private static void setRowColor(byte[] row, byte value) {
135    for (int x = 0; x < row.length; x++) {
136      row[x] = value;
137    }
138  }
139
140}