zxing/csharp/qrcode/QRCodeWriter.cs

/*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace com.google.zxing.qrcode
{
    using System;
    using System.Collections;
    using com.google.zxing.common;
    using com.google.zxing.qrcode.decoder;
    using com.google.zxing.qrcode.detector;
    using com.google.zxing.qrcode.encoder;

    public sealed class QRCodeWriter : Writer
    { 
          private static  int QUIET_ZONE_SIZE = 4;
          public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height)
          {
              try{
                return encode(contents, format, width, height, null);
              }catch(Exception e){
                throw new WriterException(e.Message);
              }            
          }

          public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height,Hashtable hints)  {

            if (contents == null || contents.Length == 0) {
              throw new ArgumentException("Found empty contents");
            }

            if (format != BarcodeFormat.QR_CODE) {
              throw new ArgumentException("Can only encode QR_CODE, but got " + format);
            }

            if (width < 0 || height < 0) {
              throw new ArgumentException("Requested dimensions are too small: " + width + 'x' +
                  height);
            }

            ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.L;
            if (hints != null) {
              ErrorCorrectionLevel requestedECLevel = (ErrorCorrectionLevel) hints[EncodeHintType.ERROR_CORRECTION];
              if (requestedECLevel != null) {
                errorCorrectionLevel = requestedECLevel;
              }
            }

            QRCode code = new QRCode();
            Encoder.encode(contents, errorCorrectionLevel, code);
            return renderResult(code, width, height);
          }

          // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
          // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
          private static ByteMatrix renderResult(QRCode code, int width, int height) {
            ByteMatrix input = code.getMatrix();
            int inputWidth = input.width();
            int inputHeight = input.height();
            int qrWidth = inputWidth + (QUIET_ZONE_SIZE << 1);
            int qrHeight = inputHeight + (QUIET_ZONE_SIZE << 1);
            int outputWidth = Math.Max(width, qrWidth);
            int outputHeight = Math.Max(height, qrHeight);

            int multiple = Math.Min(outputWidth / qrWidth, outputHeight / qrHeight);
            // Padding includes both the quiet zone and the extra white pixels to accomodate the requested
            // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
            // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
            // handle all the padding from 100x100 (the actual QR) up to 200x160.
            int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
            int topPadding = (outputHeight - (inputHeight * multiple)) / 2;

            ByteMatrix output = new ByteMatrix(outputHeight, outputWidth);
            sbyte[][] outputArray = output.getArray();

            // We could be tricky and use the first row in each set of multiple as the temporary storage,
            // instead of allocating this separate array.
            sbyte[] row = new sbyte[outputWidth];

            // 1. Write the white lines at the top
            for (int y = 0; y < topPadding; y++) {
              setRowColor(outputArray[y], unchecked((sbyte)255));
            }

            // 2. Expand the QR image to the multiple
            sbyte[][] inputArray = input.getArray();
            for (int y = 0; y < inputHeight; y++) {
              // a. Write the white pixels at the left of each row
              for (int x = 0; x < leftPadding; x++) {
                row[x] = unchecked((sbyte) 255);
              }

              // b. Write the contents of this row of the barcode
              int offset = leftPadding;
              for (int x = 0; x < inputWidth; x++) {
                sbyte value = (inputArray[y][x] == 1) ? (sbyte) 0 : unchecked((sbyte) 255);
                for (int z = 0; z < multiple; z++) {
                  row[offset + z] = value;
                }
                offset += multiple;
              }

              // c. Write the white pixels at the right of each row
              offset = leftPadding + (inputWidth * multiple);
              for (int x = offset; x < outputWidth; x++) {
                row[x] = unchecked((sbyte) 255);
              }

              // d. Write the completed row multiple times
              offset = topPadding + (y * multiple);
              for (int z = 0; z < multiple; z++) {
                System.Array.Copy(row, 0, outputArray[offset + z], 0, outputWidth);
              }
            }

            // 3. Write the white lines at the bottom
            int offset2 = topPadding + (inputHeight * multiple);
            for (int y = offset2; y < outputHeight; y++)
            {
              setRowColor(outputArray[y], unchecked((sbyte) 255));
            }
            return output;
          }

          private static void setRowColor(sbyte[] row, sbyte value) {
            for (int x = 0; x < row.Length; x++) {
              row[x] = value;
            }
          }
    
    }
}